Authoring devfilesCreating a devfile

Authoring devfiles

Creating devfiles

Most dev tools can utilize the devfile registry to fetch the stacks needed to begin development on projects. Sometimes, however, you might need to create a devfile from scratch or to create your own devfile template(s). This guide runs through the process, starting from a minimum devfile and building sample templates for common use cases.

Prerequisites

Procedure

  1. Creating a minimal devfile:
    • schemaVersion is the only required root element
    • metadata is optional but it is recommended to have in your templates

    Minimal Devfile

    devfile.yaml
    schemaVersion: 2.3.0
    

    Minimal Devfile with Metadata

    devfile.yaml
    schemaVersion: 2.3.0
    metadata:
      name: devfile-sample
      version: 2.0.0
    
  2. Creating a web service template:
    1. Template metadata
      • Set the template name and version
      • Set a description for the template
      • Set the projectType and language to describe what kind of stack is being used
      • Set provider to tell who is providing this template
      • Set tags to give keyword which describe the elements of the stack
      • Set architectures to specify the platforms support in the template
      • For improved readability on devfile registries, set displayName to the title that will be the display text for this template and icon to tie a stack icon to the template:
        schemaVersion: 2.3.0
        metadata:
          name: web-service
          version: 1.0.0
          description: A web service template.
          projectType: Go
          language: Go
          provider: Red Hat
          tags: [ 'Go', 'Gin', 'pq' ]
          architectures: [ 'amd64' ]
          displayName: Simple Web Service
          icon: https://raw.githubusercontent.com/devfile-samples/devfile-stack-icons/main/golang.svg
      
    2. Setup components
      • A name is required for a component
      • If a container entity is defined, an image property must be specified
      • Though endpoints is optional, it is needed to expose the port for web connections and requires:
        • An endpoint name
        • A targetPort to expose, for example, 8080 if that is your http port
      • The web service might need to connect to an external database using environment variables. In this case, define environment variable names and values for the container component under env:
      components:
        - name: web
          container:
            endpoints:
              - name: http
                targetPort: 8080
            env:
              DATABASE_HOST: db.example.com
              DATABASE_PORT: 5432
              DATABASE_NAME: dev
              DATABASE_USER: devuser
              DATABASE_PASSWORD: devpassword
            image: quay.io/devfile/golang:latest
      
    3. Adding commands
      • An id to identify the command
      • An exec entity must be defined with a commandLine string and a reference to a component
        • This implies that at least one component entity is defined under the root components element
      • The workingDir is set to where the project source is stored
      • Command groups can be used to define automation that is useful for executing a web service:
      commands:
        - id: build
          exec:
            commandLine: go build main.go
            component: web
            workingDir: ${PROJECT_SOURCE}
            group:
              kind: build
              isDefault: true
        - id: run
          exec:
            commandLine: ./main
            component: web
            workingDir: ${PROJECT_SOURCE}
            group:
              kind: run
              isDefault: true
      
    4. Define starter projects
      • Add a starter project under starterProjects including at least a name and remote location, either git or zip
      • It is recommended to include a starter project description:
        starterProjects:
          - name: web-starter
            description: A web service starting point.
            git:
              remotes:
                origin: https://github.com/devfile-samples/devfile-stack-go.git
        
    5. Completing the content, the complete devfile should look like the following:

    Complete Web Service Template

    devfile.yaml
    schemaVersion: 2.3.0
    metadata:
      name: web-service
      version: 1.0.0
      description: A web service template.
      projectType: Go
      language: Go
      provider: Red Hat
      tags: [ 'Go', 'Gin', 'pq' ]
      architectures: [ 'amd64' ]
      displayName: Simple Web Service
      icon: https://raw.githubusercontent.com/devfile-samples/devfile-stack-icons/main/golang.svg
    components:
      - name: web
        container:
          endpoints:
            - name: http
              targetPort: 8080
          env:
            DATABASE_HOST: db.example.com
            DATABASE_PORT: 5432
            DATABASE_NAME: dev
            DATABASE_USER: devuser
            DATABASE_PASSWORD: devpassword
          image: quay.io/devfile/golang:latest
    commands:
      - id: build
        exec:
          commandLine: go build main.go
          component: web
          workingDir: ${PROJECT_SOURCE}
          group:
            kind: build
            isDefault: true
      - id: run
        exec:
          commandLine: ./main
          component: web
          workingDir: ${PROJECT_SOURCE}
          group:
            kind: run
            isDefault: true
    starterProjects:
      - name: web-starter
        description: A web service starting point.
        git:
          remotes:
            origin: https://github.com/devfile-samples/devfile-stack-go.git
    

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