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How To: Mount volumes in a composition step where source is inside the Codefresh Volume

This article describes how to mount a volume within a named Docker volume to overcome the Docker limitation.

NOTE
This article is relevant when docker-compose.yml file in the composition step.

Overview

Compositions steps can only mount ${{CF_VOLUME_NAME}}:${{CF_VOLUME_PATH}}.

If you need to mount /codefresh/volume/<REPO>/<DIR>/ to /<DIR>, due to a Docker limitation, you cannot specify a directory inside a named Docker volume. See here.

How to

Scenario
  • Sample data in Git repo must be mounted to /database directory.
  • The custom image needs access to /database for proper execution.
  • The Dockerfile already runs a script on container startup.
Sample docker-compose.yml
version: '3.0' 
services: 
  database: 
    image: myimage:1.0.2 
    volumes: 
      - ./:/database
Sample codefresh.yml
version: 1.0

stages:
  - Clone
  - Build
  - Test

steps:

  main_clone:
    title: Cloning Repo
    type: git-clone
    stage: Clone
    arguments:
      repo: ${{CF_REPO_OWNER}}/${{CF_REPO_NAME}}
      git: cf-support-bot
      revision: ${{CF_REVISION}}

  conform:
    title: Fix docker compose
    type: composition-editor:1.1.0
    stage: Build
    arguments:
      DIRECTORY: ${{CF_VOLUME_PATH}}/${{CF_REPO_NAME}}
      YAMLFILE: docker-compose.yml
      CONFORM_COMPOSITION: true
      KEYVALUE_PAIRS:
        - services.database.volumes.0=${{CF_VOLUME_NAME}}:${{CF_VOLUME_PATH}}
        - services.database.command=bash -c "ln -s ${{CF_VOLUME_PATH}}/${{CF_REPO_NAME}} /database && ./start.sh"

  composition:
    title: Running Composition
    type: composition
    stage: Test
    arguments:
      composition: docker-compose.yml
      composition_candidates:
        test_service:
          image: alpine
          command: sleep 20
          volumes:
            - ${{CF_VOLUME_NAME}}:${{CF_VOLUME_PATH}}

In the step conform.arguments.KEYVALUE_PAIRS:

  • Volumes mount is replaced by ${{CF_VOLUME_NAME}}:${{CF_VOLUME_PATH}}.
  • The command bash -c "ln -s ${{CF_VOLUME_PATH}}/${{CF_REPO_NAME}}/<DIR>/ /database && ./start.sh":
    • Symlinks the directory in the Git repo to the /database directory
    • Executes the script already in the container

Once this is done, composition steps will run and have the correct mounts and directories where needed.

Composition steps in pipelines
Pipeline definitions YAML