Config Expressions

Config expressions are a powerful feature to load the devspace.yaml in a more dynamic way. A config expression works by specifying $( my bash expression ) instead of a field and the stdout of the bash expression is taken as value for the option or complete section. Config expressions are evaluated after variables and profiles are applied to the config and can change parts of the config.

Load From File

Load a deployment specification from file:

deployments: $(cat deployment.yaml)

If Else

You can use either inline or multi-line if else:

deployments:
    
  # Inline If-Else
  backend: $( [ ${DEVSPACE_NAMESPACE} == "test" ] && cat deployment.yaml || echo "" )

  # Multi-Line If-Else
  frontend: |-
    $(
      if [ ${DEVSPACE_CONTEXT} == "minikube" ]; then
        cat minikube.yaml
      else
        echo ""
      fi
    )

Only in dev

Disable image building during devspace dev:

images:
  deploy:
    build:
      disabled: $( [ $1 == "dev" ] && echo "true" || echo "false" )

Generate Section

Generate a whole section through a script:

dev: $(./my-script.sh ${DEVSPACE_NAMESPACE} ${DEVSPACE_CONTEXT} ${DEVSPACE_PROFILE})

Return JSON

Since json is a subset of yaml, you can also return regular json in a expression:

images:
  test:
    image: my-image/image
    build: '$( echo {"disabled": true} )'

Force String

By default, DevSpace will try to convert the stdout to a number, bool or yaml value, however you can also force the return value to be a string by using $!():

deployments:
  backend:
    helm:
      chart: ...
      values:
        labels:
          test: '$!(echo true)'

info

Expressions are run in a golang shell that is syntax compatible to a regular POSIX shell and works on all operating systems. Check the github repository for a complete list of available commands

info

Variables are resolved before and after applying expressions, which means that you can load a section from file within an expression that contains a variable which will still be resolved afterwards.

Testing Config Expressions

The command devspace print can be used to test your config expressions and shows the config after all profiles, variables and expressions were applied.