Examples

Real-world workflow examples.

Simple Job

name: hello world
tasks:
  - name: say hello
    image: ubuntu:mantic
    run: echo hello world

Using Inputs

Inputs can be used in env values and other fields (but NOT in run):

name: input example
inputs:
  message: hello world
  count: 5
tasks:
  - name: use inputs
    image: alpine:latest
    env:
      MESSAGE: '{{ inputs.message }}'
      COUNT: '{{ inputs.count }}'
    run: |
      for i in $(seq 1 $COUNT); do
        echo "$MESSAGE"
      done

Each Task (Loop)

Use each to run a task for each item in a list:

name: process items
inputs:
  items: '[1, 2, 3, 4, 5]'
tasks:
  - name: process each
    each:
      list: '{{ fromJSON(inputs.items) }}'
      concurrency: 2
      task:
        image: alpine:latest
        env:
          ITEM: '{{ item.value }}'
          INDEX: '{{ item.index }}'
        run: echo "Item $ITEM at index $INDEX"

Parallel Tasks

Run multiple tasks concurrently:

name: parallel work
tasks:
  - name: parallel parent
    parallel:
      tasks:
        - name: task a
          image: alpine:latest
          run: echo "A done"
        - name: task b
          image: alpine:latest
          run: sleep 2 && echo "B done"
        - name: task c
          image: alpine:latest
          run: echo "C done"

Conditional Execution

Use if to conditionally run tasks:

name: conditional workflow
inputs:
  environment: production
tasks:
  - name: deploy
    if: "{{ job.state == 'SCHEDULED' }}"
    image: alpine:latest
    run: echo "Deploying..."

Retry on Failure

name: with retry
tasks:
  - name: may fail
    retry:
      limit: 3
    image: alpine:latest
    run: ./might-fail.sh

Resource Limits

name: limited task
tasks:
  - name: constrained
    limits:
      cpus: "0.5"
      memory: "256m"
    image: alpine:latest
    run: echo hello

Mounts

Share data between pre/post tasks and main task:

name: with mounts
tasks:
  - name: process
    image: jrottenberg/ffmpeg:3.4-alpine
    run: ffmpeg -i /tmp/input.mov /tmp/output.mp4
    mounts:
      - type: volume
        target: /tmp
    pre:
      - name: download
        image: alpine:latest
        run: wget http://example.com/video.mov -O /tmp/input.mov

Scheduled Job

name: daily backup
schedule:
  cron: "0 2 * * *"
tasks:
  - name: backup
    image: postgres:15
    run: pg_dump -a mydb > /backups/dump.sql

Environment Variable Reference

Variable	Description
`TWERK_OUTPUT`	Write task output here

Supported Expressions

Works in env values, image, queue, name, var, if:

{{ inputs.key }} — Job inputs
{{ secrets.key }} — Job secrets
{{ item.value }} — Each loop item value
{{ item.index }} — Each loop item index

Built-in functions:

fromJSON(string) — Parse JSON string
toJSON(value) — Convert to JSON
sequence(start, stop) — Generate integer range
split(string, delimiter) — Split string
len(array) — Array length
contains(array, item) — Check membership

Works in if condition:

job.state — Current job state
job.id — Job ID
job.name — Job name
task.state — Current task state
task.id — Task ID

Note: The run field is NOT evaluated — it’s passed as raw shell script to the container.

Twerk