Awesome

Worker

Worker is the component of Travis CI that will run a CI job on some form of compute instance.

It's responsible for getting the bash script from travis-build, spinning up the compute instance (VM, Docker container, LXD container, or maybe something different), uploading the bash script, running it, and streaming the logs back to travis-logs. It also sends state updates to travis-hub.

Installing

from binary

Find the version you wish to install on the GitHub Releases page and download either the darwin-amd64 binary for macOS or the linux-amd64 binary for Linux. No other operating systems or architectures have pre-built binaries at this time.

from package

Use the ./bin/travis-worker-install script, or take a look at the packagecloud instructions.

from snap

Using a linux distribution which supports Snaps you can run: sudo snap install travis-worker --edge

from source

install Go v1.7+
clone this down into your $GOPATH

mkdir -p $GOPATH/src/github.com/travis-ci
git clone https://github.com/travis-ci/worker $GOPATH/src/github.com/travis-ci/worker
cd $GOPATH/src/github.com/travis-ci/worker

install gometalinter:

go get -u github.com/alecthomas/gometalinter
gometalinter --install

install shellcheck
make

Configuring Travis Worker

Travis Worker is configured with environment variables or command line flags via the urfave/cli library. A list of the non-dynamic flags and environment variables may be found by invoking the built-in help system:

travis-worker --help

Environment-based image selection configuration

Some backend providers support image selection based on environment variables. The required format uses keys that are prefixed with the provider-specific prefix:

TRAVIS_WORKER_{UPPERCASE_PROVIDER}_IMAGE_{UPPERCASE_NAME}: contains an image name string to be used by the backend provider

The following example is for use with the Docker backend:

# matches on `dist: trusty`
export TRAVIS_WORKER_DOCKER_IMAGE_DIST_TRUSTY=travisci/ci-connie:packer-1420290255-fafafaf

# matches on `dist: bionic`
export TRAVIS_WORKER_DOCKER_IMAGE_DIST_BIONIC=registry.business.com/fancy/ubuntu:bionic

# resolves for `language: ruby`
export TRAVIS_WORKER_DOCKER_IMAGE_RUBY=registry.business.com/travisci/ci-ruby:whatever

# resolves for `group: edge` + `language: python`
export TRAVIS_WORKER_DOCKER_IMAGE_GROUP_EDGE_PYTHON=travisci/ci-garnet:packer-1530230255-fafafaf

# used when no dist, language, or group matches
export TRAVIS_WORKER_DOCKER_IMAGE_DEFAULT=travisci/ci-garnet:packer-1410230255-fafafaf

Development: Running Travis Worker locally

This section is for anyone wishing to contribute code to Worker. The code itself should have godoc-compatible docs (which can be viewed on godoc.org: https://godoc.org/github.com/travis-ci/worker), this is mainly a higher-level overview of the code.

Environment

Ensure you've defined the necessary environment variables (see .example.env).

Pull Docker images

docker pull travisci/ci-amethyst:packer-1504724461
docker tag travisci/ci-amethyst:packer-1504724461 travis:default

Configuration

For configuration, there are some things like the job-board (TRAVIS_WORKER_JOB_BOARD_URL) and travis-build (TRAVIS_WORKER_BUILD_API_URI) URLs that need to be set. These can be set to the staging values.

export TRAVIS_WORKER_JOB_BOARD_URL='https://travis-worker:API_KEY@job-board-staging.travis-ci.com'
export TRAVIS_WORKER_BUILD_API_URI='https://x:API_KEY@build-staging.travis-ci.org/script'

TRAVIS_WORKER_BUILD_API_URI can be found in the env of the job board app, e.g.: heroku config:get JOB_BOARD_BUILD_API_ORG_URL -a job-board-staging.

Images

TODO

Configuring the requested provider/backend

Each provider requires its own configuration, which must be provided via environment variables namespaced by TRAVIS_WORKER_{PROVIDER}_.

Docker

The backend should be configured to be Docker, e.g.:

export TRAVIS_WORKER_PROVIDER_NAME='docker'
export TRAVIS_WORKER_DOCKER_ENDPOINT=unix:///var/run/docker.sock        # or "tcp://localhost:4243"
export TRAVIS_WORKER_DOCKER_PRIVILEGED="false"                          # optional
export TRAVIS_WORKER_DOCKER_CERT_PATH="/etc/secret-docker-cert-stuff"   # optional

Queue configuration

File-based queue

For the queue configuration, there is a file-based queue implementation so you don't have to mess around with RabbitMQ.

You can generate a payload via the generate-job-payload.rb script on travis-scheduler:

heroku run -a travis-scheduler-staging script/generate-job-payload.rb <job id> > payload.json

Place the file in the $TRAVIS_WORKER_QUEUE_NAME/10-created.d/ directory, where it will be picked up by the worker.

See example-payload.json for an example payload.

AMQP-based queue

export TRAVIS_WORKER_QUEUE_TYPE='amqp'
export TRAVIS_WORKER_AMQP_URI='amqp://guest:guest@localhost'

The web interface is accessible at http://localhost:15672/

To verify your messages are being published, try:

rabbitmqadmin get queue=reporting.jobs.builds

Note: You will first need to install rabbitmqadmin. See http://localhost:15672/cli

See script/publish-example-payload for a script to enqueue example-payload.json.

Building and running

Run make build after making any changes. make also executes the test suite.

make
${GOPATH%%:*}/bin/travis-worker

or in Docker (FIXME):

docker build -t travis-worker . # or docker pull travisci/worker
docker run --env-file ENV_FILE -ti travis-worker # or travisci/worker

Testing

Run make test. To run backend tests matching Docker, for example, run go test -v ./backend -test.run Docker.

Verifying and exporting configuration

To inspect the parsed configuration in a format that can be used as a base environment variable configuration, use the --echo-config flag, which will exit immediately after writing to stdout:

travis-worker --echo-config

Stopping Travis Worker

Travis Worker has two shutdown modes: Graceful and immediate. The graceful shutdown will tell the worker to not start any additional jobs but finish the jobs it is currently running before it shuts down. The immediate shutdown will make the worker stop the jobs it's working on, requeue them, and clean up any open resources (shut down VMs, cleanly close connections, etc.)

To start a graceful shutdown, send an INT signal to the worker (for example using kill -INT). To start an immediate shutdown, send a TERM signal to the worker (for example using kill -TERM).

Go dependency management

Travis Worker is built via the standard go commands and dependencies managed by using Go Modules.

Release process

Since we want to easily keep track of worker changes, we often associate them with a version number. To find out the current version, check the changelog or run travis-worker --version. We typically use semantic versioning to determine how to increase this number.

Once you've decided what the next version number should be, update the changelog making sure you include all relevant changes that happened since the previous version was tagged. You can see these by running git diff vX.X.X...HEAD, where v.X.X.X is the name of the previous version.

Once the changelog has been updated and merged to master, the merge commit needs to be signed and manually tagged with the version number. To do this, run:

git tag --sign -a vX.X.X -m "Worker version vX.X.X"
git push origin vX.X.X

The Travis build corresponding to this push should build and upload a worker image with the new tag to Dockerhub.

The next step is to create a new Github release tag with the appropriate information from the changelog.

License and Copyright Information

See LICENSE file.