Commands, env vars, quotes and more in Semaphore

semaphore.yml

version: v1.0
name: Commands in Semaphore
agent:
  machine:
    type: e1-standard-2
    os_image: ubuntu2004

queue:
  processing: parallel

blocks:
  - name: Run a variety of commands
    dependencies: []
    task:
      jobs:
        - name: Dump all available environment variables
          commands:
            - env | sort
        - name: Use the value of an environment variable
          commands:
            # Double quotes work with dollar sign before variable name
            - echo "We're running in a $SEMAPHORE_AGENT_MACHINE_ENVIRONMENT_TYPE"
            # Command logged: echo "We're running in a $SEMAPHORE_AGENT_MACHINE_ENVIRONMENT_TYPE"
            # Command output: We're running in a VM

            # Double quotes and dollar curly braces also works, helps when part of a longer string.
            - echo "The current shell is ${SHELL}"

            #  This won't work, must use double-quotes for variable interpolation
            - echo 'The current shell is $SHELL'
            # Command logged: echo 'The current shell is $SHELL'
            # Command output: The current shell is $SHELL

        - name: Use quotes and a variable inside quoted command
          commands:
            # Use single quotes to wrap the command instead.
            - 'echo "Current shell is ${SHELL}"'
            # This also works.
            - "echo \"Current shell is ${SHELL}\""
            # But this does not work.
            - "echo 'Current shell is ${SHELL}'"


        - name: Single-line if statement - But why?
          commands:
            - if [ ! -d /tmp/coverage ]; then mkdir /tmp/coverage && echo "Created dir"; else echo "Skipping dir creation"; fi

        - name: Single-line test
          commands:
            # Needs quotes or `- |` and a new line because of the first character being `[` which is yaml for
            # the start of an array.
            - "[[ ! -d /tmp/coverage ]] && mkdir /tmp/coverage && echo 'Created dir'"

        - name: Multi-line command - Get IP address
          commands:
            # Dumb example to split across lines, but it's just an example. No line-continuation characters required.
            - >-
              curl
              -X GET
              "https://checkip.amazonaws.com"

        - name: Multi-line if statement - Create /tmp/coverage directory
          commands:
          - |
            if [ ! -d /tmp/coverage ]; then
              mkdir /tmp/coverage
              echo "Created /tmp/coverage inside a $SEMAPHORE_AGENT_MACHINE_ENVIRONMENT_TYPE"
            fi
          - echo "Multi-line if statement done."

        - name: Multi-line if statement with multi-line commands
          commands:
          - |
            if [ ! -d /tmp/coverage ]; then
              curl \
              -X GET \
              "https://checkip.amazonaws.com"
              mkdir /tmp/coverage
              echo "Created /tmp/coverage inside a $SEMAPHORE_AGENT_MACHINE_ENVIRONMENT_TYPE"
            fi
          - echo "Multi-line if statement done."

        - name: Multi-line with if condition, multi-line json, curl and check response code
          commands:
            - >-
              if [ "$SOMETHING" == "passed" ]; then
                echo "Skipping curl."
              else
                echo "Post event to somewhere, because SOMETHING is ${SOMETHING}"
                json_data='{
                    "key": "value",
                    "moar_keys": "moar_better",
                    "tags": [
                      "some_tag_1:'${ENV_VAR_1}'",
                      "some_tag_2:'${ENV_VAR_2}'"
                    ]
                }'
                echo "Posting the following JSON"
                echo "$json_data"
                response_code=$(curl -s -o /dev/null -w "%{http_code}" -X POST \
                  "https://dummy.url" \
                  -H "Accept: application/json" \
                  -H "Content-Type: application/json" \
                  -d "$json_data" )
                echo "Response code from curl request was $response_code"
              fi

        - name: Create a new environment variable and reference it in the same job
          commands:
            # Use this for dynamic values. For static values set `env_vars:` on the job, task or pipeline.
            - MY_IP=$(curl "https://checkip.amazonaws.com")
            - echo "My apparent public IP address is ${MY_IP}"


        - name: Export a value to use in another job - IP address and app version
          commands:
            # Use the sem-context cli as a key-value store to pass data between jobs, blocks and
            # pipelines in the same workflow.
            - sem-context put MY_IP=$(curl "https://checkip.amazonaws.com") --force
            - sem-context put APP_VERSION=${SEMAPHORE_SCALA_VERSION}

  - name: Run commands using the output from another task
    dependencies: ["Run a variety of commands"]
    task:
      jobs:
        - name: Echo variable set in previous job - IP address and app version
          commands:
            - RESTORED_IP_VAULE=$(sem-context get MY_IP)
            - echo "The IP address from the previous task was recorded as ${RESTORED_IP_VAULE}"
            - echo "Read directly from the key-value store, the IP address was $(sem-context get MY_IP)"
            - echo "App Version is $(sem-context get APP_VERSION)"