Docker Compose to Kubernetes YAML conversion

The specctl -m d2k, that is, mode Docker Compose to Kubernetes will convert Compose files to Kubernetes YAMLs. The services section in Docker Compose is used to create - Kubernetes Service, Kubernetes Deployment, and the pod specification within the deployment.

Simple example of nginx

specctl -m d2k -s tests/docker_compose/nginx/docker_compose.yml

Note: It is better to provide and convert one docker_compose file at a time. Why? Read on.

Docker Compose relies heavily on files. For example, Compose can have build construct to build and use the container image. Or, environment can have values that are provided in env files. To handle these scenarios -e, --env_file option is added. In this env_file you can have all the values you want to assign to the environment variables and you can also set the build images. To avoid a mess of wrong value assignment and headaches of multiple env files and docker compose files, I recommend doing conversions one docker compose file at a time. You can always create a shell loop if you have many docker compose files to convert.

An example with the environment file. The docker compose sample courtesy of open source project - plane

specctl -m d2k -s tests/docker_compose/plane/docker_compose.yml -e tests/docker_compose/plane/env
2023-06-08 22:56:48,110 [WARNING] specctl.dc2k8s.dc_parser: plane-web service has no container image. looking up ${BUILD_plane-web} in env file
2023-06-08 22:56:48,110 [WARNING] specctl.dc2k8s.dc_parser: BUILD_plane-web key is not found in env file
2023-06-08 22:56:48,111 [WARNING] specctl.dc2k8s.dc_parser: NEXT_PUBLIC_API_BASE_URL key is not found in env file
...
...
...
...
2023-06-08 22:56:48,149 [WARNING] specctl.dc2k8s.dc_parser: plane-proxy service has no container image. looking up ${BUILD_plane-proxy} in env file
2023-06-08 22:56:48,153 [Level 100] specctl.dc2k8s.dc_reader_writer: Please see ./output directory for kubernetes artifacts

Note: plane-web-service is using build construct. So we look for ${BUILD_plane-web} in the passed env_file (the -e option). Naturally, first you run this you will not know what all build constructs are there. That is okay note the log messages, add the variables to the env file and re-run the command. The specctl will pick up the values from env file. Similarly, if there are environment variables with missing values, such as NEXT_PUBLIC_API_BASE_URL in above example, those are highlighted in the logger messages as well.

We will update the below list as the support for Docker Compose evolves, in particular the service attributes: - [X] Handle service, image, and ports - [X] Build construct to build and use an image instead of image url - [X] Handling replacement of environment variables
- [ ] Command and entry point - [ ] Deploy - [ ] Config - [ ] Volumes - [ ] Side car via network mode matching - [ ] Daemons / global deploy attribute - [ ] ?