awscrt.mqtt5

MQTT5

class awscrt.mqtt5.QoS(value)

MQTT message delivery quality of service.

Enum values match MQTT5 spec encoding values.

AT_MOST_ONCE = 0

The message is delivered according to the capabilities of the underlying network. No response is sent by the receiver and no retry is performed by the sender. The message arrives at the receiver either once or not at all.

AT_LEAST_ONCE = 1

A level of service that ensures that the message arrives at the receiver at least once.

EXACTLY_ONCE = 2

A level of service that ensures that the message arrives at the receiver exactly once.

Note that this client does not currently support QoS 2 as of (August 2022)

class awscrt.mqtt5.ConnectReasonCode(value)

Server return code for connect attempts.

Enum values match MQTT5 spec encoding values.

SUCCESS = 0

Returned when the connection is accepted.

UNSPECIFIED_ERROR = 128

Returned when the server has a failure but does not want to specify a reason or none of the other reason codes apply.

MALFORMED_PACKET = 129

Returned when data in the CONNECT packet could not be correctly parsed by the server.

PROTOCOL_ERROR = 130

Returned when data in the CONNECT packet does not conform to the MQTT5 specification requirements.

IMPLEMENTATION_SPECIFIC_ERROR = 131

Returned when the CONNECT packet is valid but was not accepted by the server.

UNSUPPORTED_PROTOCOL_VERSION = 132

Returned when the server does not support MQTT5 protocol version specified in the connection.

CLIENT_IDENTIFIER_NOT_VALID = 133

Returned when the client identifier in the CONNECT packet is a valid string but not one that is allowed on the server.

BAD_USERNAME_OR_PASSWORD = 134

Returned when the server does not accept the username and/or password specified by the client in the connection packet.

NOT_AUTHORIZED = 135

Returned when the client is not authorized to connect to the server.

SERVER_UNAVAILABLE = 136

Returned when the MQTT5 server is not available.

SERVER_BUSY = 137

Returned when the server is too busy to make a connection. It is recommended that the client try again later.

BANNED = 138

Returned when the client has been banned by the server.

BAD_AUTHENTICATION_METHOD = 140

Returned when the authentication method used in the connection is either not supported on the server or it does not match the authentication method currently in use in the CONNECT packet.

TOPIC_NAME_INVALID = 144

Returned when the Will topic name sent in the CONNECT packet is correctly formed, but is not accepted by the server.

PACKET_TOO_LARGE = 149

Returned when the CONNECT packet exceeded the maximum permissible size on the server.

QUOTA_EXCEEDED = 151

Returned when the quota limits set on the server have been met and/or exceeded.

PAYLOAD_FORMAT_INVALID = 153

Returned when the Will payload in the CONNECT packet does not match the specified payload format indicator.

RETAIN_NOT_SUPPORTED = 154

Returned when the server does not retain messages but the CONNECT packet on the client had Will retain enabled.

QOS_NOT_SUPPORTED = 155

Returned when the server does not support the QOS setting set in the Will QOS in the CONNECT packet.

USE_ANOTHER_SERVER = 156

Returned when the server is telling the client to temporarily use another server instead of the one they are trying to connect to.

SERVER_MOVED = 157

Returned when the server is telling the client to permanently use another server instead of the one they are trying to connect to.

CONNECTION_RATE_EXCEEDED = 159

Returned when the server connection rate limit has been exceeded.

class awscrt.mqtt5.DisconnectReasonCode(value)

Reason code inside DISCONNECT packets. Helps determine why a connection was terminated.

Enum values match MQTT5 spec encoding values.

NORMAL_DISCONNECTION = 0

Returned when the remote endpoint wishes to disconnect normally. Will not trigger the publish of a Will message if a Will message was configured on the connection.

May be sent by the client or server.

DISCONNECT_WITH_WILL_MESSAGE = 4

Returns when the client wants to disconnect but requires that the server publish the Will message configured on the connection.

May only be sent by the client.

UNSPECIFIED_ERROR = 128

Returned when the connection was closed but the sender does not want to specify a reason or none of the other reason codes apply.

May be sent by the client or the server.

MALFORMED_PACKET = 129

Indicates the remote endpoint received a packet that does not conform to the MQTT specification.

May be sent by the client or the server.

PROTOCOL_ERROR = 130

Returned when an unexpected or out-of-order packet was received by the remote endpoint.

May be sent by the client or the server.

IMPLEMENTATION_SPECIFIC_ERROR = 131

Returned when a valid packet was received by the remote endpoint, but could not be processed by the current implementation.

May be sent by the client or the server.

NOT_AUTHORIZED = 135

Returned when the remote endpoint received a packet that represented an operation that was not authorized within the current connection.

May only be sent by the server.

SERVER_BUSY = 137

Returned when the server is busy and cannot continue processing packets from the client.

May only be sent by the server.

SERVER_SHUTTING_DOWN = 139

Returned when the server is shutting down.

May only be sent by the server.

KEEP_ALIVE_TIMEOUT = 141

Returned when the server closes the connection because no packet from the client has been received in 1.5 times the KeepAlive time set when the connection was established.

May only be sent by the server.

SESSION_TAKEN_OVER = 142

Returned when the server has established another connection with the same client ID as a client’s current connection, causing the current client to become disconnected.

May only be sent by the server.

TOPIC_FILTER_INVALID = 143

Returned when the topic filter name is correctly formed but not accepted by the server.

May only be sent by the server.

TOPIC_NAME_INVALID = 144

Returned when topic name is correctly formed, but is not accepted.

May be sent by the client or the server.

RECEIVE_MAXIMUM_EXCEEDED = 147

Returned when the remote endpoint reached a state where there were more in-progress QoS1+ publishes then the limit it established for itself when the connection was opened.

May be sent by the client or the server.

TOPIC_ALIAS_INVALID = 148

Returned when the remote endpoint receives a PUBLISH packet that contained a topic alias greater than the maximum topic alias limit that it established for itself when the connection was opened.

May be sent by the client or the server.

PACKET_TOO_LARGE = 149

Returned when the remote endpoint received a packet whose size was greater than the maximum packet size limit it established for itself when the connection was opened.

May be sent by the client or the server.

MESSAGE_RATE_TOO_HIGH = 150

Returned when the remote endpoint’s incoming data rate was too high.

May be sent by the client or the server.

QUOTA_EXCEEDED = 151

Returned when an internal quota of the remote endpoint was exceeded.

May be sent by the client or the server.

ADMINISTRATIVE_ACTION = 152

Returned when the connection was closed due to an administrative action.

May be sent by the client or the server.

PAYLOAD_FORMAT_INVALID = 153

Returned when the remote endpoint received a packet where payload format did not match the format specified by the payload format indicator.

May be sent by the client or the server.

RETAIN_NOT_SUPPORTED = 154

Returned when the server does not support retained messages.

May only be sent by the server.

QOS_NOT_SUPPORTED = 155

Returned when the client sends a QoS that is greater than the maximum QoS established when the connection was opened.

May only be sent by the server.

USE_ANOTHER_SERVER = 156

Returned by the server to tell the client to temporarily use a different server.

May only be sent by the server.

SERVER_MOVED = 157

Returned by the server to tell the client to permanently use a different server.

May only be sent by the server.

SHARED_SUBSCRIPTIONS_NOT_SUPPORTED = 158

Returned by the server to tell the client that shared subscriptions are not supported on the server.

May only be sent by the server.

CONNECTION_RATE_EXCEEDED = 159

Returned when the server disconnects the client due to the connection rate being too high.

May only be sent by the server.

MAXIMUM_CONNECT_TIME = 160

Returned by the server when the maximum connection time authorized for the connection was exceeded.

May only be sent by the server.

SUBSCRIPTION_IDENTIFIERS_NOT_SUPPORTED = 161

Returned by the server when it received a SUBSCRIBE packet with a subscription identifier, but the server does not support subscription identifiers.

May only be sent by the server.

WILDCARD_SUBSCRIPTIONS_NOT_SUPPORTED = 162

Returned by the server when it received a SUBSCRIBE packet with a wildcard topic filter, but the server does not support wildcard topic filters.

May only be sent by the server.

class awscrt.mqtt5.PubackReasonCode(value)

Reason code inside PUBACK packets that indicates the result of the associated PUBLISH request.

Enum values match MQTT5 spec encoding values.

SUCCESS = 0

Returned when the (QoS 1) publish was accepted by the recipient.

May be sent by the client or the server.

NO_MATCHING_SUBSCRIBERS = 16

Returned when the (QoS 1) publish was accepted but there were no matching subscribers.

May only be sent by the server.

UNSPECIFIED_ERROR = 128

Returned when the (QoS 1) publish was not accepted and the receiver does not want to specify a reason or none of the other reason codes apply.

May be sent by the client or the server.

IMPLEMENTATION_SPECIFIC_ERROR = 131

Returned when the (QoS 1) publish was valid but the receiver was not willing to accept it.

May be sent by the client or the server.

NOT_AUTHORIZED = 135

Returned when the (QoS 1) publish was not authorized by the receiver.

May be sent by the client or the server.

TOPIC_NAME_INVALID = 144

Returned when the topic name was valid but the receiver was not willing to accept it.

May be sent by the client or the server.

PACKET_IDENTIFIER_IN_USE = 145

Returned when the packet identifier used in the associated PUBLISH was already in use. This can indicate a mismatch in the session state between client and server.

May be sent by the client or the server.

QUOTA_EXCEEDED = 151

Returned when the associated PUBLISH failed because an internal quota on the recipient was exceeded.

May be sent by the client or the server.

PAYLOAD_FORMAT_INVALID = 153

Returned when the PUBLISH packet’s payload format did not match its payload format indicator property.

May be sent by the client or the server.

class awscrt.mqtt5.SubackReasonCode(value)

Reason code inside SUBACK packet payloads.

Enum values match MQTT5 spec encoding values.

This will only be sent by the server and not the client.

GRANTED_QOS_0 = 0

Returned when the subscription was accepted and the maximum QoS sent will be QoS 0.

GRANTED_QOS_1 = 1

Returned when the subscription was accepted and the maximum QoS sent will be QoS 1.

GRANTED_QOS_2 = 2

Returned when the subscription was accepted and the maximum QoS sent will be QoS 2.

UNSPECIFIED_ERROR = 128

Returned when the connection was closed but the sender does not want to specify a reason or none of the other reason codes apply.

IMPLEMENTATION_SPECIFIC_ERROR = 131

Returned when the subscription was valid but the server did not accept it.

NOT_AUTHORIZED = 135

Returned when the client was not authorized to make the subscription on the server.

TOPIC_FILTER_INVALID = 143

Returned when the subscription topic filter was correctly formed but not allowed for the client.

PACKET_IDENTIFIER_IN_USE = 145

Returned when the packet identifier was already in use on the server.

QUOTA_EXCEEDED = 151

Returned when a subscribe-related quota set on the server was exceeded.

SHARED_SUBSCRIPTIONS_NOT_SUPPORTED = 158

Returned when the subscription’s topic filter was a shared subscription and the server does not support shared subscriptions.

SUBSCRIPTION_IDENTIFIERS_NOT_SUPPORTED = 161

Returned when the SUBSCRIBE packet contained a subscription identifier and the server does not support subscription identifiers.

WILDCARD_SUBSCRIPTIONS_NOT_SUPPORTED = 162

Returned when the subscription’s topic filter contains a wildcard but the server does not support wildcard subscriptions.

class awscrt.mqtt5.UnsubackReasonCode(value)

Reason codes inside UNSUBACK packet payloads that specify the results for each topic filter in the associated UNSUBSCRIBE packet.

Enum values match MQTT5 spec encoding values.

SUCCESS = 0

Returned when the unsubscribe was successful and the client is no longer subscribed to the topic filter on the server.

NO_SUBSCRIPTION_EXISTED = 17

Returned when the topic filter did not match one of the client’s existing topic filters on the server.

UNSPECIFIED_ERROR = 128

Returned when the unsubscribe of the topic filter was not accepted and the server does not want to specify a reason or none of the other reason codes apply.

IMPLEMENTATION_SPECIFIC_ERROR = 131

Returned when the topic filter was valid but the server does not accept an unsubscribe for it.

NOT_AUTHORIZED = 135

Returned when the client was not authorized to unsubscribe from that topic filter on the server.

TOPIC_FILTER_INVALID = 143

Returned when the topic filter was correctly formed but is not allowed for the client on the server.

PACKET_IDENTIFIER_IN_USE = 145

Returned when the packet identifier was already in use on the server.

class awscrt.mqtt5.ClientSessionBehaviorType(value)

Controls how the mqtt client should behave with respect to MQTT sessions.

DEFAULT = 0

Default client session behavior. Maps to CLEAN.

CLEAN = 1

Always ask for a clean session when connecting

REJOIN_POST_SUCCESS = 2

Always attempt to rejoin an existing session after an initial connection success.

Session rejoin requires an appropriate non-zero session expiry interval in the client’s CONNECT options.

REJOIN_ALWAYS = 3

Always attempt to rejoin an existing session. Since the client does not support durable session persistence, this option is not guaranteed to be spec compliant because any unacknowledged qos1 publishes (which are part of the client session state) will not be present on the initial connection. Until we support durable session resumption, this option is technically spec-breaking, but useful.

Always rejoin requires an appropriate non-zero session expiry interval in the client’s CONNECT options.

class awscrt.mqtt5.PayloadFormatIndicator(value)

Optional property describing a PUBLISH payload’s format.

Enum values match MQTT5 spec encoding values.

AWS_MQTT5_PFI_BYTES = 0

The payload is arbitrary binary data

AWS_MQTT5_PFI_UTF8 = 1

The payload is a well-formed utf-8 string value.

class awscrt.mqtt5.RetainHandlingType(value)

Configures how retained messages should be handled when subscribing with a topic filter that matches topics with associated retained messages.

Enum values match MQTT5 spec encoding values.

SEND_ON_SUBSCRIBE = 0

The server should always send all retained messages on topics that match a subscription’s filter.

SEND_ON_SUBSCRIBE_IF_NEW = 1

The server should send retained messages on topics that match the subscription’s filter, but only for the first matching subscription, per session.

DONT_SEND = 2

Subscriptions must not trigger any retained message publishes from the server.

class awscrt.mqtt5.RetainAndHandlingType(value)

DEPRECATED.

RetainAndHandlingType is deprecated, please use RetainHandlingType

SEND_ON_SUBSCRIBE = 0

The server should always send all retained messages on topics that match a subscription’s filter.

SEND_ON_SUBSCRIBE_IF_NEW = 1

The server should send retained messages on topics that match the subscription’s filter, but only for the first matching subscription, per session.

DONT_SEND = 2

Subscriptions must not trigger any retained message publishes from the server.

class awscrt.mqtt5.ExtendedValidationAndFlowControlOptions(value)

Additional controls for client behavior with respect to operation validation and flow control; these checks go beyond the MQTT5 spec to respect limits of specific MQTT brokers.

NONE = 0

Do not do any additional validation or flow control

AWS_IOT_CORE_DEFAULTS = 1

Apply additional client-side validation and operational flow control that respects the default AWS IoT Core limits.

Currently applies the following additional validation:

• No more than 8 subscriptions per SUBSCRIBE packet

• Topics and topic filters have a maximum of 7 slashes (8 segments), not counting any AWS rules prefix

• Topics must be 256 bytes or less in length

• Client id must be 128 or less bytes in length

Also applies the following flow control:

• Outbound throughput throttled to 512KB/s

• Outbound publish TPS throttled to 100

class awscrt.mqtt5.ClientOperationQueueBehaviorType(value)

Controls how disconnects affect the queued and in-progress operations tracked by the client. Also controls how operations are handled while the client is not connected. In particular, if the client is not connected, then any operation that would be failed on disconnect (according to these rules) will be rejected.

DEFAULT = 0

Default client operation queue behavior. Maps to FAIL_QOS0_PUBLISH_ON_DISCONNECT.

FAIL_NON_QOS1_PUBLISH_ON_DISCONNECT = 1

Re-queues QoS 1+ publishes on disconnect; un-acked publishes go to the front while unprocessed publishes stay in place. All other operations (QoS 0 publishes, subscribe, unsubscribe) are failed.

FAIL_QOS0_PUBLISH_ON_DISCONNECT = 2

QoS 0 publishes that are not complete at the time of disconnection are failed. Un-acked QoS 1+ publishes are re-queued at the head of the line for immediate retransmission on a session resumption. All other operations are requeued in original order behind any retransmissions.

FAIL_ALL_ON_DISCONNECT = 3

All operations that are not complete at the time of disconnection are failed, except operations that the MQTT5 spec requires to be retransmitted (un-acked QoS1+ publishes).

class awscrt.mqtt5.ExponentialBackoffJitterMode(value)

Controls how the reconnect delay is modified in order to smooth out the distribution of reconnection attempt timepoints for a large set of reconnecting clients.

See Exponential Backoff and Jitter

DEFAULT = 0

Maps to Full

NONE = 1

Do not perform any randomization on the reconnect delay

FULL = 2

Fully random between no delay and the current exponential backoff value.

DECORRELATED = 3

Backoff is taken randomly from the interval between the base backoff interval and a scaling (greater than 1) of the current backoff value

class awscrt.mqtt5.UserProperty(name: str | None = None, value: str | None = None)

MQTT5 User Property

Parameters:

• name (str) – Property name

• value (str) – Property value

class awscrt.mqtt5.OutboundTopicAliasBehaviorType(value)

An enumeration that controls how the client applies topic aliasing to outbound publish packets.

Topic alias behavior is described in MQTT5 Topic Aliasing

DEFAULT = 0

Maps to Disabled. This keeps the client from being broken (by default) if the broker topic aliasing implementation has a problem.

MANUAL = 1

Outbound aliasing is the user’s responsibility. Client will cache and use previously-established aliases if they fall within the negotiated limits of the connection.

The user must still always submit a full topic in their publishes because disconnections disrupt topic alias mappings unpredictably. The client will properly use a requested alias when the most-recently-seen binding for a topic alias value matches the alias and topic in the publish packet.

LRU = 2

(Recommended) The client will ignore any user-specified topic aliasing and instead use an LRU cache to drive alias usage.

DISABLED = 3

Completely disable outbound topic aliasing.

class awscrt.mqtt5.InboundTopicAliasBehaviorType(value)

An enumeration that controls whether or not the client allows the broker to send publishes that use topic

aliasing.

Topic alias behavior is described in MQTT5 Topic Aliasing

DEFAULT = 0

Maps to Disabled. This keeps the client from being broken (by default) if the broker topic aliasing implementation has a problem.

ENABLED = 1

Allow the server to send PUBLISH packets to the client that use topic aliasing

DISABLED = 2

Forbid the server from sending PUBLISH packets to the client that use topic aliasing

class awscrt.mqtt5.TopicAliasingOptions(outbound_behavior: OutboundTopicAliasBehaviorType | None = None, outbound_cache_max_size: int | None = None, inbound_behavior: InboundTopicAliasBehaviorType | None = None, inbound_cache_max_size: int | None = None)

Configuration for all client topic aliasing behavior.

Parameters:

• outbound_behavior (OutboundTopicAliasBehaviorType) – Controls what kind of outbound topic aliasing behavior the client should attempt to use. If topic aliasing is not supported by the server, this setting has no effect and any attempts to directly manipulate the topic alias id in outbound publishes will be ignored. If left undefined, then outbound topic aliasing is disabled.

• outbound_cache_max_size (int) – If outbound topic aliasing is set to LRU, this controls the maximum size of the cache. If outbound topic aliasing is set to LRU and this is zero or undefined, a sensible default is used (25). If outbound topic aliasing is not set to LRU, then this setting has no effect.

• inbound_behavior (InboundTopicAliasBehaviorType) – Controls whether or not the client allows the broker to use topic aliasing when sending publishes. Even if inbound topic aliasing is enabled, it is up to the server to choose whether or not to use it. If left undefined, then inbound topic aliasing is disabled.

• inbound_cache_max_size (int) – If inbound topic aliasing is enabled, this will control the size of the inbound alias cache. If inbound aliases are enabled and this is zero or undefined, then a sensible default will be used (25). If inbound aliases are disabled, this setting has no effect. Behaviorally, this value overrides anything present in the topic_alias_maximum field of the CONNECT packet options.

class awscrt.mqtt5.NegotiatedSettings(maximum_qos: QoS | None = None, session_expiry_interval_sec: int | None = None, receive_maximum_from_server: int | None = None, maximum_packet_size_to_server: int | None = None, topic_alias_maximum_to_server: int | None = None, topic_alias_maximum_to_client: int | None = None, server_keep_alive_sec: int | None = None, retain_available: bool | None = None, wildcard_subscriptions_available: bool | None = None, subscription_identifiers_available: bool | None = None, shared_subscriptions_available: bool | None = None, rejoined_session: bool | None = None, client_id: str | None = None)

Mqtt behavior settings that are dynamically negotiated as part of the CONNECT/CONNACK exchange.

While you can infer all of these values from a combination of: - defaults as specified in the mqtt5 spec - your CONNECT settings - the CONNACK from the broker

the client instead does the combining for you and emits a NegotiatedSettings object with final, authoritative values.

Negotiated settings are communicated with every successful connection establishment.

Parameters:

• maximum_qos (QoS) – The maximum QoS allowed for publishes on this connection instance

• session_expiry_interval_sec (int) – The amount of time in seconds the server will retain the MQTT session after a disconnect.

• receive_maximum_from_server (int) – The number of in-flight QoS 1 and QoS 2 publications the server is willing to process concurrently.

• maximum_packet_size_to_server (int) – The maximum packet size the server is willing to accept.

• topic_alias_maximum_to_server (int) – the maximum allowed topic alias value on publishes sent from client to server

• topic_alias_maximum_to_client (int) – the maximum allowed topic alias value on publishes sent from server to client

• server_keep_alive_sec (int) – The maximum amount of time in seconds between client packets. The client will use PINGREQs to ensure this limit is not breached. The server will disconnect the client for inactivity if no MQTT packet is received in a time interval equal to 1.5 x this value.

• retain_available (bool) – Whether the server supports retained messages.

• wildcard_subscriptions_available (bool) – Whether the server supports wildcard subscriptions.

• subscription_identifiers_available (bool) – Whether the server supports subscription identifiers

• shared_subscriptions_available (bool) – Whether the server supports shared subscriptions

• rejoined_session (bool) – Whether the client has rejoined an existing session.

• client_id (str) – The final client id in use by the newly-established connection. This will be the configured client id if one was given in the configuration, otherwise, if no client id was specified, this will be the client id assigned by the server. Reconnection attempts will always use the auto-assigned client id, allowing for auto-assigned session resumption.

class awscrt.mqtt5.ConnackPacket(session_present: bool = None, reason_code: ConnectReasonCode = None, session_expiry_interval_sec: int = None, receive_maximum: int = None, maximum_qos: QoS = None, retain_available: bool = None, maximum_packet_size: int = None, assigned_client_identifier: str = None, topic_alias_maximum: int = None, reason_string: str = None, user_properties: Sequence[UserProperty] = None, wildcard_subscriptions_available: bool = None, subscription_identifiers_available: bool = None, shared_subscription_available: bool = None, server_keep_alive_sec: int = None, response_information: str = None, server_reference: str = None)

Data model of an MQTT5 CONNACK packet.

Parameters:

• session_present (bool) – True if the client rejoined an existing session on the server, false otherwise.

• reason_code (ConnectReasonCode) – Indicates either success or the reason for failure for the connection attempt. session_expiry_interval_sec (int): A time interval, in seconds, that the server will persist this connection’s MQTT session state for. If present, this value overrides any session expiry specified in the preceding CONNECT packet.

• receive_maximum (int) – The maximum amount of in-flight QoS 1 or 2 messages that the server is willing to handle at once. If omitted or None, the limit is based on the valid MQTT packet id space (65535).

• maximum_qos (QoS) – The maximum message delivery quality of service that the server will allow on this connection.

• retain_available (bool) – Indicates whether the server supports retained messages. If None, retained messages are supported.

• maximum_packet_size (int) – Specifies the maximum packet size, in bytes, that the server is willing to accept. If None, there is no limit beyond what is imposed by the MQTT spec itself.

• assigned_client_identifier (str) – Specifies a client identifier assigned to this connection by the server. Only valid when the client id of the preceding CONNECT packet was left empty.

• topic_alias_maximum (int) – The maximum allowed value for topic aliases in outbound publish packets. If 0 or None, then outbound topic aliasing is not allowed.

• reason_string (str) – Additional diagnostic information about the result of the connection attempt.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

• wildcard_subscriptions_available (bool) – Indicates whether the server supports wildcard subscriptions. If None, wildcard subscriptions are supported.

• subscription_identifiers_available (bool) – Indicates whether the server supports subscription identifiers. If None, subscription identifiers are supported.

• shared_subscription_available (bool) – Indicates whether the server supports shared subscription topic filters. If None, shared subscriptions are supported.

• server_keep_alive (int) – DEPRECATED. Please use server_keep_alive_sec.

• server_keep_alive_sec (int) – Server-requested override of the keep alive interval, in seconds. If None, the keep alive value sent by the client should be used.

• response_information (str) – A value that can be used in the creation of a response topic associated with this connection. MQTT5-based request/response is outside the purview of the MQTT5 spec and this client.

• server_reference (str) – Property indicating an alternate server that the client may temporarily or permanently attempt to connect to instead of the configured endpoint. Will only be set if the reason code indicates another server may be used (ServerMoved, UseAnotherServer).

class awscrt.mqtt5.DisconnectPacket(reason_code: DisconnectReasonCode = DisconnectReasonCode.NORMAL_DISCONNECTION, session_expiry_interval_sec: int = None, reason_string: str = None, user_properties: Sequence[UserProperty] = None, server_reference: str = None)

Data model of an MQTT5 DISCONNECT packet.

Parameters:

• reason_code (DisconnectReasonCode) – Value indicating the reason that the sender is closing the connection

• session_expiry_interval_sec (int) – A change to the session expiry interval negotiated at connection time as part of the disconnect. Only valid for DISCONNECT packets sent from client to server. It is not valid to attempt to change session expiry from zero to a non-zero value.

• reason_string (str) – Additional diagnostic information about the reason that the sender is closing the connection

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

• server_reference (str) – Property indicating an alternate server that the client may temporarily or permanently attempt to connect to instead of the configured endpoint. Will only be set if the reason code indicates another server may be used (ServerMoved, UseAnotherServer).

class awscrt.mqtt5.Subscription(topic_filter: str, qos: QoS = QoS.AT_MOST_ONCE, no_local: bool = False, retain_as_published: bool = False, retain_handling_type: RetainHandlingType = RetainHandlingType.SEND_ON_SUBSCRIBE)

Configures a single subscription within a Subscribe operation

Parameters:

• topic_filter (str) – The topic filter to subscribe to

• qos (QoS) – The maximum QoS on which the subscriber will accept publish messages

• no_local (bool) – Whether the server will not send publishes to a client when that client was the one who sent the publish

• retain_as_published (bool) – Whether messages sent due to this subscription keep the retain flag preserved on the message

• retain_handling_type (RetainHandlingType) – Whether retained messages on matching topics be sent in reaction to this subscription

class awscrt.mqtt5.SubscribePacket(subscriptions: Sequence[Subscription], subscription_identifier: int = None, user_properties: Sequence[UserProperty] = None)

Data model of an MQTT5 SUBSCRIBE packet.

Parameters:

• subscriptions (Sequence[Subscription]) – The list of topic filters that the client wishes to listen to

• subscription_identifier (int) – The positive int to associate with all topic filters in this request. Publish packets that match a subscription in this request should include this identifier in the resulting message.

• user_properties (Sequence[UserProperty]) – The list of MQTT5 user properties included with the packet.

class awscrt.mqtt5.SubackPacket(reason_string: str = None, user_properties: Sequence[UserProperty] = None, reason_codes: Sequence[SubackReasonCode] = None)

Data model of an MQTT5 SUBACK packet.

Parameters:

• reason_string (str) – Additional diagnostic information about the result of the SUBSCRIBE attempt.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

• reason_codes (Sequence[SubackReasonCode]) – List of reason codes indicating the result of each individual subscription entry in the associated SUBSCRIBE packet.

class awscrt.mqtt5.UnsubscribePacket(topic_filters: Sequence[str], user_properties: Sequence[UserProperty] = None)

Data model of an MQTT5 UNSUBSCRIBE packet.

Parameters:

• topic_filters (Sequence[str]) – List of topic filters that the client wishes to unsubscribe from.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

class awscrt.mqtt5.UnsubackPacket(reason_string: str = None, user_properties: Sequence[UserProperty] = None, reason_codes: Sequence[DisconnectReasonCode] = None)

Data model of an MQTT5 UNSUBACK packet.

Parameters:

• reason_string (str) – Additional diagnostic information about the result of the UNSUBSCRIBE attempt.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

• reason_codes (Sequence[DisconnectReasonCode]) – A list of reason codes indicating the result of unsubscribing from each individual topic filter entry in the associated UNSUBSCRIBE packet.

class awscrt.mqtt5.PublishPacket(payload: Any = '', qos: QoS = QoS.AT_MOST_ONCE, retain: bool = False, topic: str = '', payload_format_indicator: PayloadFormatIndicator = None, message_expiry_interval_sec: int = None, topic_alias: int = None, response_topic: str = None, correlation_data: Any = None, subscription_identifiers: Sequence[int] = None, content_type: str = None, user_properties: Sequence[UserProperty] = None)

Data model of an MQTT5 PUBLISH packet

Parameters:

• payload (Any) – The payload of the publish message.

• qos (QoS) – The MQTT quality of service associated with this PUBLISH packet.

• retain (bool) – True if this is a retained message, false otherwise.

• topic (str) – The topic associated with this PUBLISH packet.

• payload_format_indicator (PayloadFormatIndicator) – Property specifying the format of the payload data. The mqtt5 client does not enforce or use this value in a meaningful way.

• message_expiry_interval_sec (int) – Sent publishes - indicates the maximum amount of time allowed to elapse for message delivery before the server should instead delete the message (relative to a recipient). Received publishes - indicates the remaining amount of time (from the server’s perspective) before the message would have been deleted relative to the subscribing client. If left None, indicates no expiration timeout.

• topic_alias (int) – An integer value that is used to identify the Topic instead of using the Topic Name. On outbound publishes, this will only be used if the outbound topic aliasing behavior has been set to Manual.

• response_topic (str) – Opaque topic string intended to assist with request/response implementations. Not internally meaningful to MQTT5 or this client.

• correlation_data (Any) – Opaque binary data used to correlate between publish messages, as a potential method for request-response implementation. Not internally meaningful to MQTT5.

• subscription_identifiers (Sequence[int]) – The subscription identifiers of all the subscriptions this message matched.

• content_type (str) – Property specifying the content type of the payload. Not internally meaningful to MQTT5.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

class awscrt.mqtt5.PubackPacket(reason_code: PubackReasonCode = None, reason_string: str = None, user_properties: Sequence[UserProperty] = None)

Data model of an MQTT5 PUBACK packet

Parameters:

• reason_code (PubackReasonCode) – Success indicator or failure reason for the associated PUBLISH packet.

• reason_string (str) – Additional diagnostic information about the result of the PUBLISH attempt.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

class awscrt.mqtt5.ConnectPacket(keep_alive_interval_sec: int = None, client_id: str = None, username: str = None, password: str = None, session_expiry_interval_sec: int = None, request_response_information: bool = None, request_problem_information: bool = None, receive_maximum: int = None, maximum_packet_size: int = None, will_delay_interval_sec: int = None, will: PublishPacket = None, user_properties: Sequence[UserProperty] = None)

Data model of an MQTT5 CONNECT packet.

Parameters:

• keep_alive_interval_sec (int) – The maximum time interval, in seconds, that is permitted to elapse between the point at which the client finishes transmitting one MQTT packet and the point it starts sending the next. The client will use PINGREQ packets to maintain this property. If the responding CONNACK contains a keep alive property value, then that is the negotiated keep alive value. Otherwise, the keep alive sent by the client is the negotiated value.

• client_id (str) – A unique string identifying the client to the server. Used to restore session state between connections. If left empty, the broker will auto-assign a unique client id. When reconnecting, the mqtt5 client will always use the auto-assigned client id.

• username (str) – A string value that the server may use for client authentication and authorization.

• password (str) – Opaque binary data that the server may use for client authentication and authorization.

• session_expiry_interval_sec (int) – A time interval, in seconds, that the client requests the server to persist this connection’s MQTT session state for. Has no meaning if the client has not been configured to rejoin sessions. Must be non-zero in order to successfully rejoin a session. If the responding CONNACK contains a session expiry property value, then that is the negotiated session expiry value. Otherwise, the session expiry sent by the client is the negotiated value.

• request_response_information (bool) – If true, requests that the server send response information in the subsequent CONNACK. This response information may be used to set up request-response implementations over MQTT, but doing so is outside the scope of the MQTT5 spec and client.

• request_problem_information (bool) – If true, requests that the server send additional diagnostic information (via response string or user properties) in DISCONNECT or CONNACK packets from the server.

• receive_maximum (int) – Notifies the server of the maximum number of in-flight QoS 1 and 2 messages the client is willing to handle. If omitted or None, then no limit is requested.

• maximum_packet_size (int) – Notifies the server of the maximum packet size the client is willing to handle. If omitted or None, then no limit beyond the natural limits of MQTT packet size is requested.

• will_delay_interval_sec (int) – A time interval, in seconds, that the server should wait (for a session reconnection) before sending the will message associated with the connection’s session. If omitted or None, the server will send the will when the associated session is destroyed. If the session is destroyed before a will delay interval has elapsed, then the will must be sent at the time of session destruction.

• will (PublishPacket) – The definition of a message to be published when the connection’s session is destroyed by the server or when the will delay interval has elapsed, whichever comes first. If None, then nothing will be sent.

• user_properties (Sequence[UserProperty]) – List of MQTT5 user properties included with the packet.

class awscrt.mqtt5.WebsocketHandshakeTransformArgs(client, http_request, done_future)

Argument to a “websocket_handshake_transform” function.

A websocket_handshake_transform function has signature: fn(transform_args: WebsocketHandshakeTransformArgs) -> None

The function implementer may modify transform_args.http_request as desired. They MUST call transform_args.set_done() when complete, passing an exception if something went wrong. Failure to call set_done() will hang the application.

The implementer may do asynchronous work before calling transform_args.set_done(), they are not required to call set_done() within the scope of the transform function. An example of async work would be to fetch credentials from another service, sign the request headers, and finally call set_done() to mark the transform complete.

The default websocket handshake request uses path “/mqtt”. All required headers are present, plus the optional header “Sec-WebSocket-Protocol: mqtt”.

Parameters:

• client (Client) – Client this handshake is for.

• http_request (awscrt.http.HttpRequest) – HTTP request for this handshake.

• done_future (concurrent.futures.Future) – Future to complete when the set_done() is called. It will contain None if successful, or an exception will be set.

client

Client this handshake is for.

Type:

Client

http_request

HTTP request for this handshake.

Type:

awscrt.http.HttpRequest

set_done(exception=None)

Mark the transformation complete. If exception is passed in, the handshake is canceled.

class awscrt.mqtt5.PublishReceivedData(publish_packet: PublishPacket | None = None)

Dataclass containing data related to a Publish Received Callback

Parameters:

publish_packet (PublishPacket) –

Data model of an MQTT5 PUBLISH packet.

class awscrt.mqtt5.OperationStatisticsData(incomplete_operation_count: int = 0, incomplete_operation_size: int = 0, unacked_operation_count: int = 0, unacked_operation_size: int = 0)

Dataclass containing some simple statistics about the current state of the client’s queue of operations

Parameters:

• incomplete_operation_count (int) – total number of operations submitted to the client that have not yet been completed. Unacked operations are a subset of this.

• incomplete_operation_size (int) – total packet size of operations submitted to the client that have not yet been completed. Unacked operations are a subset of this.

• unacked_operation_count (int) – total number of operations that have been sent to the server and are waiting for a corresponding ACK before they can be completed.

• unacked_operation_size (int) – total packet size of operations that have been sent to the server and are waiting for a corresponding ACK before they can be completed.

class awscrt.mqtt5.LifecycleStoppedData

Dataclass containing results of an Stopped Lifecycle Event Currently Unused

class awscrt.mqtt5.LifecycleAttemptingConnectData

Dataclass containing results of an Attempting Connect Lifecycle Event Currently Unused

class awscrt.mqtt5.LifecycleConnectSuccessData(connack_packet: ConnackPacket | None = None, negotiated_settings: NegotiatedSettings | None = None)

Dataclass containing results of a Connect Success Lifecycle Event

Parameters:

• connack_packet (ConnackPacket) –

  Data model of an MQTT5 CONNACK packet.

• negotiated_settings – (NegotiatedSettings): Mqtt behavior settings that have been dynamically negotiated as part of the CONNECT/CONNACK exchange.

class awscrt.mqtt5.LifecycleConnectFailureData(connack_packet: ConnackPacket | None = None, exception: Exception | None = None)

Dataclass containing results of a Connect Failure Lifecycle Event

Parameters:

• connack_packet (ConnackPacket) –

  Data model of an MQTT5 CONNACK packet.

• error_code (int) – (awscrt.exceptions.AwsCrtError): Exception which caused connection failure.

class awscrt.mqtt5.LifecycleDisconnectData(disconnect_packet: DisconnectPacket | None = None, exception: Exception | None = None)

Dataclass containing results of a Disconnect Lifecycle Event

Parameters:

• disconnect_packet (DisconnectPacket) –

  Data model of an MQTT5 DISCONNECT packet.

• error_code (int) – (awscrt.exceptions.AwsCrtError): Exception which caused disconnection.

class awscrt.mqtt5.PublishCompletionData(puback: PubackPacket | None = None)

Dataclass containing results of a Publish

Parameters:

puback (PubackPacket) – On a successful completion of a QoS1 publish a PubackPacket will be included.

class awscrt.mqtt5.ClientOptions(host_name: str, port: int | None = None, bootstrap: ClientBootstrap | None = None, socket_options: SocketOptions | None = None, tls_ctx: ClientTlsContext | None = None, http_proxy_options: HttpProxyOptions | None = None, websocket_handshake_transform: Callable[[WebsocketHandshakeTransformArgs], None] | None = None, connect_options: ConnectPacket | None = None, session_behavior: ClientSessionBehaviorType | None = None, extended_validation_and_flow_control_options: ExtendedValidationAndFlowControlOptions | None = None, offline_queue_behavior: ClientOperationQueueBehaviorType | None = None, retry_jitter_mode: ExponentialBackoffJitterMode | None = None, min_reconnect_delay_ms: int | None = None, max_reconnect_delay_ms: int | None = None, min_connected_time_to_reset_reconnect_delay_ms: int | None = None, ping_timeout_ms: int | None = None, connack_timeout_ms: int | None = None, ack_timeout_sec: int | None = None, topic_aliasing_options: TopicAliasingOptions | None = None, on_publish_callback_fn: Callable[[PublishReceivedData], None] | None = None, on_lifecycle_event_stopped_fn: Callable[[LifecycleStoppedData], None] | None = None, on_lifecycle_event_attempting_connect_fn: Callable[[LifecycleAttemptingConnectData], None] | None = None, on_lifecycle_event_connection_success_fn: Callable[[LifecycleConnectSuccessData], None] | None = None, on_lifecycle_event_connection_failure_fn: Callable[[LifecycleConnectFailureData], None] | None = None, on_lifecycle_event_disconnection_fn: Callable[[LifecycleDisconnectData], None] | None = None)

Configuration for the creation of MQTT5 clients

Parameters:

• host_name (str) – Host name of the MQTT server to connect to.

• port (int) – Network port of the MQTT server to connect to.

• bootstrap (ClientBootstrap) – The Client bootstrap used

• socket_options (SocketOptions) – The socket properties of the underlying MQTT connections made by the client or None if defaults are used.

• tls_ctx (ClientTlsContext) – The TLS context for secure socket connections. If None, then a plaintext connection will be used.

• http_proxy_options (HttpProxyOptions) – The (tunneling) HTTP proxy usage when establishing MQTT connections

• websocket_handshake_transform (Callable[[WebsocketHandshakeTransformArgs],]) – This callback allows a custom transformation of the HTTP request that acts as the websocket handshake. Websockets will be used if this is set to a valid transformation callback. To use websockets but not perform a transformation, just set this as a trivial completion callback. If None, the connection will be made with direct MQTT.

• connect_options (ConnectPacket) – All configurable options with respect to the CONNECT packet sent by the client, including the will. These connect properties will be used for every connection attempt made by the client.

• session_behavior (ClientSessionBehaviorType) – How the MQTT5 client should behave with respect to MQTT sessions.

• extended_validation_and_flow_control_options (ExtendedValidationAndFlowControlOptions) – The additional controls for client behavior with respect to operation validation and flow control; these checks go beyond the base MQTT5 spec to respect limits of specific MQTT brokers.

• offline_queue_behavior (ClientOperationQueueBehaviorType) – Returns how disconnects affect the queued and in-progress operations tracked by the client. Also controls how new operations are handled while the client is not connected. In particular, if the client is not connected, then any operation that would be failed on disconnect (according to these rules) will also be rejected.

• retry_jitter_mode (ExponentialBackoffJitterMode) – How the reconnect delay is modified in order to smooth out the distribution of reconnection attempt timepoints for a large set of reconnecting clients.

• min_reconnect_delay_ms (int) – The minimum amount of time to wait to reconnect after a disconnect. Exponential backoff is performed with jitter after each connection failure.

• max_reconnect_delay_ms (int) – The maximum amount of time to wait to reconnect after a disconnect. Exponential backoff is performed with jitter after each connection failure.

• min_connected_time_to_reset_reconnect_delay_ms (int) – The amount of time that must elapse with an established connection before the reconnect delay is reset to the minimum. This helps alleviate bandwidth-waste in fast reconnect cycles due to permission failures on operations.

• ping_timeout_ms (int) – The time interval to wait after sending a PINGREQ for a PINGRESP to arrive. If one does not arrive, the client will close the current connection.

• connack_timeout_ms (int) – The time interval to wait after sending a CONNECT request for a CONNACK to arrive. If one does not arrive, the connection will be shut down.

• ack_timeout_sec (int) – The time interval to wait for an ack after sending a QoS 1+ PUBLISH, SUBSCRIBE, or UNSUBSCRIBE before failing the operation.

• topic_aliasing_options (TopicAliasingOptions) – All configurable options with respect to client topic aliasing behavior.

• on_publish_callback_fn (Callable[[PublishReceivedData],]) – Callback for all publish packets received by client.

• on_lifecycle_event_stopped_fn (Callable[[LifecycleStoppedData],]) – Callback for Lifecycle Event Stopped.

• on_lifecycle_event_attempting_connect_fn (Callable[[LifecycleAttemptingConnectData],]) – Callback for Lifecycle Event Attempting Connect.

• on_lifecycle_event_connection_success_fn (Callable[[LifecycleConnectSuccessData],]) – Callback for Lifecycle Event Connection Success.

• on_lifecycle_event_connection_failure_fn (Callable[[LifecycleConnectFailureData],]) – Callback for Lifecycle Event Connection Failure.

• on_lifecycle_event_disconnection_fn (Callable[[LifecycleDisconnectData],]) – Callback for Lifecycle Event Disconnection.

class awscrt.mqtt5.Client(client_options: ClientOptions)

This class wraps the aws-c-mqtt MQTT5 client to provide the basic MQTT5 pub/sub functionalities via the AWS Common Runtime

One Client class creates one connection.

Parameters:

client_options (ClientOptions) – The ClientOptions dataclass to used to configure the new Client.

start()

Notifies the MQTT5 client that you want it maintain connectivity to the configured endpoint. The client will attempt to stay connected using the properties of the reconnect-related parameters in the mqtt5 client configuration.

This is an asynchronous operation.

stop(disconnect_packet: DisconnectPacket | None = None)

Notifies the MQTT5 client that you want it to end connectivity to the configured endpoint, disconnecting any existing connection and halting any reconnect attempts.

This is an asynchronous operation.

Parameters:

disconnect_packet (DisconnectPacket) – (optional) Properties of a DISCONNECT packet to send as part of the shutdown process

publish(publish_packet: PublishPacket)

Tells the client to attempt to send a PUBLISH packet.

Will return a future containing a PubAckResult if the publish is successful. The data in the PubAckResult varies depending on the QoS of the Publish. For QoS 0, the PubAckResult will not contain data. For QoS 1, the PubAckResult will contain a PubAckPacket. See PubAckResult class documentation for more info.

Parameters:

publish_packet (PublishPacket) – PUBLISH packet to send to the server

Returns:

A future with a (PublishCompletionData)

subscribe(subscribe_packet: SubscribePacket)

Tells the client to attempt to subscribe to one or more topic filters.

Parameters:

subscribe_packet (SubscribePacket) – SUBSCRIBE packet to send to the server

Returns:

A future with a (SubackPacket)

unsubscribe(unsubscribe_packet: UnsubscribePacket)

Tells the client to attempt to unsubscribe from one or more topic filters.

Parameters:

unsubscribe_packet (UnsubscribePacket) – UNSUBSCRIBE packet to send to the server

Returns:

A future with a (UnsubackPacket)

get_stats()

Queries the client’s internal statistics for incomplete operations.

Returns:

The (OperationStatisticsData) containing the statistics