[](https://travis-ci.org/ory/dockertest?branch=master) [](https://coveralls.io/github/ory/dockertest?branch=v3) Use Docker to run your Golang integration tests against third party services on **Microsoft Windows, Mac OSX and Linux**! **Table of Contents** - [Why should I use Dockertest?](#why-should-i-use-dockertest) - [Installing and using Dockertest](#installing-and-using-dockertest) - [Using Dockertest](#using-dockertest) - [Examples](#examples) - [Troubleshoot & FAQ](#troubleshoot--faq) - [Out of disk space](#out-of-disk-space) - [Removing old containers](#removing-old-containers) ## Why should I use Dockertest? When developing applications, it is often necessary to use services that talk to a database system. Unit Testing these services can be cumbersome because mocking database/DBAL is strenuous. Making slight changes to the schema implies rewriting at least some, if not all of the mocks. The same goes for API changes in the DBAL. To avoid this, it is smarter to test these specific services against a real database that is destroyed after testing. Docker is the perfect system for running unit tests as you can spin up containers in a few seconds and kill them when the test completes. The Dockertest library provides easy to use commands for spinning up Docker containers and using them for your tests. ## Installing and using Dockertest Using Dockertest is straightforward and simple. Check the [releases tab](https://github.com/ory/dockertest/releases) for available releases. To install dockertest, run ``` go get -u github.com/ory/dockertest/v3 ``` ### Using Dockertest ```go package dockertest_test import ( "database/sql" "fmt" "log" "os" "testing" _ "github.com/go-sql-driver/mysql" "github.com/ory/dockertest/v3" ) var db *sql.DB func TestMain(m *testing.M) { // uses a sensible default on windows (tcp/http) and linux/osx (socket) pool, err := dockertest.NewPool("") if err != nil { log.Fatalf("Could not construct pool: %s", err) } // uses pool to try to connect to Docker err = pool.Client.Ping() if err != nil { log.Fatalf("Could not connect to Docker: %s", err) } // pulls an image, creates a container based on it and runs it resource, err := pool.Run("mysql", "5.7", []string{"MYSQL_ROOT_PASSWORD=secret"}) if err != nil { log.Fatalf("Could not start resource: %s", err) } // exponential backoff-retry, because the application in the container might not be ready to accept connections yet if err := pool.Retry(func() error { var err error db, err = sql.Open("mysql", fmt.Sprintf("root:secret@(localhost:%s)/mysql", resource.GetPort("3306/tcp"))) if err != nil { return err } return db.Ping() }); err != nil { log.Fatalf("Could not connect to database: %s", err) } // as of go1.15 testing.M returns the exit code of m.Run(), so it is safe to use defer here defer func() { if err := pool.Purge(resource); err != nil { log.Fatalf("Could not purge resource: %s", err) } }() m.Run() } func TestSomething(t *testing.T) { // db.Query() } ``` ### Examples We provide code examples for well known services in the [examples](examples/) directory, check them out! ## Troubleshoot & FAQ ### Out of disk space Try cleaning up the images with [docker-cleanup-volumes](https://github.com/chadoe/docker-cleanup-volumes). ### Removing old containers Sometimes container clean up fails. Check out [this stackoverflow question](http://stackoverflow.com/questions/21398087/how-to-delete-dockers-images) on how to fix this. You may also set an absolute lifetime on containers: ```go resource.Expire(60) // Tell docker to hard kill the container in 60 seconds ``` To let stopped containers removed from file system automatically, use `pool.RunWithOptions()` instead of `pool.Run()` with `config.AutoRemove` set to true, e.g.: ```go postgres, err := pool.RunWithOptions(&dockertest.RunOptions{ Repository: "postgres", Tag: "11", Env: []string{ "POSTGRES_USER=test", "POSTGRES_PASSWORD=test", "listen_addresses = '*'", }, }, func(config *docker.HostConfig) { // set AutoRemove to true so that stopped container goes away by itself config.AutoRemove = true config.RestartPolicy = docker.RestartPolicy{ Name: "no", } }) ``` ## Running dockertest in Gitlab CI ### How to run dockertest on shared gitlab runners? You should add docker dind service to your job which starts in sibling container. That means database will be available on host `docker`. You app should be able to change db host through environment variable. Here is the simple example of `gitlab-ci.yml`: ```yaml stages: - test go-test: stage: test image: golang:1.15 services: - docker:dind variables: DOCKER_HOST: tcp://docker:2375 DOCKER_DRIVER: overlay2 YOUR_APP_DB_HOST: docker script: - go test ./... ``` Plus in the `pool.Retry` method that checks for connection readiness, you need to use `$YOUR_APP_DB_HOST` instead of localhost. ### How to run dockertest on group(custom) gitlab runners? Gitlab runner can be run in docker executor mode to save compatibility with shared runners. Here is the simple register command: ```shell script gitlab-runner register -n \ --url https://gitlab.com/ \ --registration-token $YOUR_TOKEN \ --executor docker \ --description "My Docker Runner" \ --docker-image "docker:19.03.12" \ --docker-privileged ``` You only need to instruct docker dind to start with disabled tls. Add variable `DOCKER_TLS_CERTDIR: ""` to `gitlab-ci.yml` above. It will tell docker daemon to start on 2375 port over http. ## Running Dockertest Using GitHub Actions ```yaml name: Test with Docker on: [push] jobs: test: runs-on: ubuntu-latest services: dind: image: docker:23.0-rc-dind-rootless ports: - 2375:2375 steps: - name: Checkout code uses: actions/checkout@v2 - name: Set up Go uses: actions/setup-go@v4 with: go-version: "1.21" - name: Test with Docker run: go test -v ./... ``` ### How to run dockertest with remote Docker Use-case: locally installed docker CLI (client), docker daemon somewhere remotely, environment properly set (ie: `DOCKER_HOST`, etc..). For example, remote docker can be provisioned by docker-machine. Currently, dockertest in case of `resource.GetHostPort()` will return docker host binding address (commonly - `localhost`) instead of remote docker host. Universal solution is: ```go func getHostPort(resource *dockertest.Resource, id string) string { dockerURL := os.Getenv("DOCKER_HOST") if dockerURL == "" { return resource.GetHostPort(id) } u, err := url.Parse(dockerURL) if err != nil { panic(err) } return u.Hostname() + ":" + resource.GetPort(id) } ``` It will return the remote docker host concatenated with the allocated port in case `DOCKER_HOST` env is defined. Otherwise, it will fall back to the embedded behavior.