DEV Community

Cover image for Build with Travis with the help of Docker
Travis CI profile image Montana Mendy
Montana Mendy for Travis CI

Posted on

Build with Travis with the help of Docker

#docker #devops #travisci #deploy

Using Docker with Travis CI by Montana Mendy

Using Docker for your Travis CI build

Okay, let's do this! Open up your favorite text editor or IDE. A classic .travis.yml file for Python would look like this:

For this example we will assume you are using python3 and below is your Dockerfile:

from python:3.6 CMD ["python", "-c", "print(12345)"]
Enter fullscreen mode Exit fullscreen mode

Next up let's build an image and run it!

docker build -t foobar . Sending build context to Docker daemon 2.048kB Step 1/2 : from python:3.6 ---> 3e4c2972dc8d Step 2/2 : CMD ["python", "-c", "print(12345)"] ---> Running in 5e3273c46264 Removing intermediate container 5e3273c46264 ---> c1d000f3a768 Successfully built c1d000f3a768 Successfully tagged foobar:latest
Enter fullscreen mode Exit fullscreen mode

The image is built using foobar as a tag in which myself, I’ll use next when running it:

docker run --rm -ti foobar 12345
Enter fullscreen mode Exit fullscreen mode

Some explanations of the arguments below:

  • --rm - Automatically removes the container when it exits
  • --tty -t - Allocate a pseudo-TTY also known as a pts
  • --interactive , -i - Keeps STDIN open even if not attached to the container

Now let's setup the Travis .yml file! As you'll notice we will be using services (as Docker is our service in this method). This file as usual should be listed as .travis.yml.

sudo: required language: python services: - docker script: - docker build -t foobar .
Enter fullscreen mode Exit fullscreen mode

Now let's say this Travis file wants to push to Amazon ECR. Keep in mind that ECR has some limits on maximum amount of tags and images.

As you see it also expects some environmental variables which I’ll provide in .travis.yml. Below is an updated script:

#!/bin/bash -e # the registry should have been created already # example my username would be: montanamendy # you could just paste a given url from AWS but I'm # parameterising it to make it more obvious how its constructed REGISTRY_URL=${AWS_ACCOUNT_ID}.dkr.ecr.${EB_REGION}.amazonaws.com # this is most likely namespaced repo name like myorg/veryimportantimage SOURCE_IMAGE="${DOCKER_REPO}" # using it as there will be 2 versions published TARGET_IMAGE="${REGISTRY_URL}/${DOCKER_REPO}" # lets make sure we always have access to latest image TARGET_IMAGE_LATEST="${TARGET_IMAGE}:latest" TIMESTAMP=$(date '+%Y%m%d%H%M%S') # using datetime as part of a version for versioned image VERSION="${TIMESTAMP}-${TRAVIS_COMMIT}" # using specific version as well # it is useful if you want to reference this particular version # in additional commands like deployment of new Elasticbeanstalk version TARGET_IMAGE_VERSIONED="${TARGET_IMAGE}:${VERSION}" # making sure correct region is set aws configure set default.region ${EB_REGION} # Push image to ECR ################### # I'm speculating it obtains temporary access token # it expects aws access key and secret set # in environmental vars $(aws ecr get-login --no-include-email) # update latest version docker tag ${SOURCE_IMAGE} ${TARGET_IMAGE_LATEST} docker push ${TARGET_IMAGE_LATEST} # push new version docker tag ${SOURCE_IMAGE} ${TARGET_IMAGE_VERSIONED} docker push ${TARGET_IMAGE_VERSIONED}
Enter fullscreen mode Exit fullscreen mode

In this scenario I pushed 2 tags, latest and versioned. AWS also has limits on this.

As you see it also expects some environmental variables which I’ll provide in .travis.yml. You'll see an updated script assuming above one was named docker_push.sh:

sudo: required language: python services: - docker env: global: - DOCKER_REPO=myorg/veryimportantimage - EB_REGION="eu-west-1" - secure: travisEncryptedAWS_ACCOUNT_ID - secure: travisEncryptedAWS_ACCESS_KEY_ID - secure: travisEncryptedAWS_SECRET_ACCESS_KEY before_install: - pip install awscli - export PATH=$PATH:$HOME/.local/bin script: - docker build -t $DOCKER_REPO . deploy: provider: script script: bash docker_push.sh on: branch: master
Enter fullscreen mode Exit fullscreen mode

Now remember to encrypt your env vars for our AWS keys, there were three of them:

  • AWS_ACCOUNT_ID
  • AWS_ACCESS_KEY_ID
  • AWS_SECRET_ACCESS_KEY

Once you make sure all the env vars open up your IDE or text editor (in my case it's vim) and reread over the Docker bash script I provided earlier and make sure it's correct (can also lint for help). Here's a screen cap of my vim environment for an example:

Alt Text

Since you have Travis installed, read this snippet of information. So we can run:

travis encrypt AWS_ACCOUNT_ID=super_secret --add
Enter fullscreen mode Exit fullscreen mode

That's it, you're now in the Docker container world with Travis!

Top comments (0)