Following are the jobs in the pipeline as per the ‘stages’ section of the .gitlab-ci.yml file:
Quality (hadolint): The hadolint
tool evaluates the Dockerfile for best practices and potential security
vulnerabilities.
Get-Version (getsquid_vars): Identifies the latest version of Squid and sets the environment variable for subsequent jobs.
Docker-hub-build (docker-hub-build) and
Docker-hub-build-arm (docker-hub-build-arm): Builds Docker
images for both amd64 and arm
architectures.
Docker-hub-test (docker-hub-test), Docker-hub-test-arm (docker-hub-test-arm), SquidParseConfig, dive, dive-arm: Test the built Docker images and configuration.
Docker-hub-pushtag (push-docker-hub) and Docker-hub-pushtag-arm (push-docker-hub-arm): Push the tested Docker images to Docker Hub.
Docs (chatgpt_analysis) and update_dockerhub_readme: Analyze the CI pipeline using OpenAI’s ChatGPT model and update Docker Hub’s README.
Each job within the pipeline performs a specific action and contributes to the overall pipeline execution.
This job is responsible for evaluating Dockerfile using the tool
named hadolint. The job is aimed at enforcing best
practices and detecting any security vulnerabilities in the
Dockerfile.
having DL3008 Dockerfile This job identifies the latest version of ‘squid’, sets it as a
variable, and passes it to subsequent jobs in the pipeline. Other
actions include updating README.md and committing/pushing
changes to the Git repository.
export SQUID_VERSION=$(curl ...These jobs build Docker images for the amd64 and
arm architectures, using the Dockerfile in the project
directory. It pulls the latest base image, interferes build arguments
for the Squid version, and tags the resulting image.
docker build -f Dockerfile --build-arg SQUID_VERSION=$SQUID_VERSION --pull -t $CONTAINER_BUILD_NOPROD_NAME_AMD64 .These jobs are aimed at testing the built Docker images and related
configuration. It verifies the Squid configuration file
(squid.conf), tests the Docker image’s connectivity with
the curl utility, and checks the Docker image size and
layer contents degradation using the dive utility.
export https_proxy=http://$CONTAINER_TEST_NAME:3128 && curl -k https://www.google.frThese jobs push the tested Docker images to Docker Hub. The jobs pull the built images, retag them appropriate tags (latest version of Squid, latest), and push them to Docker Hub.
docker pull $CONTAINER_BUILD_NOPROD_NAME_ARM
docker tag $CONTAINER_BUILD_NOPROD_NAME_ARM $HUB_REGISTRY_IMAGE:$SQUID_VERSION-arm
docker push $HUB_REGISTRY_IMAGE:$SQUID_VERSION-armThe chatgpt_analysis job uses OpenAI’s ChatGPT model to
analyze the entire CI pipeline, output the analysis result in Markdown
format. Then transferred it to a remote server.
JOBS_CONTENT=$(cat .gitlab-ci.yml gitlabci/*)The update_dockerhub_readme job updates the README of
the Docker Hub’s repository with the current content of README.md in the
project. The job makes an API request to Docker Hub to update the full
description of the repository.
README_CONTENT=$(cat README.md) There’re many important parameters, environment variables that play a significant role in the pipeline.
HUB_REGISTRY_IMAGE: The variable for the Docker Hub
repository image.DOCKER_HUB_USER, DOCKER_HUB_TOKEN:
Credentials for Docker Hub that are used in Docker login
operations.GIT_CLONE_PATH, CI_BUILDS_DIR,
CI_PROJECT_NAME, CI_COMMIT_BRANCH: These are
predefined variables in GitLab’s CI/CD pipeline.CONTAINER_CLIENT_IMAGE: The Docker image for the client
used in the pipeline.SQUID_VERSION: The variable for the Squid version
updated by the getsquid_vars job and used by subsequent
jobs.getsquid_vars and chatgpt_analysis.Several jobs in the pipeline are dependent on one another. Here’re some key dependencies:
getsquid_vars job as it provides the latest Squid
version.chatgpt_analysis job is dependent on a few jobs
(getsquid_vars, docker-hub-test,
docker-hub-test-arm) to provide the latest Squid version
and test results for analysis.push-docker-hub and
docker-hub-build-arm are allowed to execute only on the
Master branch.amd64 and arm
platforms are built and tested in the pipeline.getsquid_vars job produces the
variables.env file as an artifact, which represents the
latest Squid version.chatgpt_analysis job generates an analysis report in
both Markdown and HTML formats and these files serve as artifacts
too.The latest commit info is aadae10 Exclude skip tag.
This commit’s purpose is to exclude jobs in the pipeline when commit
message includes [skip ci]. This allows developers to push
commits that do not trigger the CI/CD pipeline, saving computing
resources for more necessary operations. It can also provide developers
with a way to skip the pipeline for minor changes or when working on
experimental features that don’t need to test their impacts on other
components in the pipeline.
In this pipeline, Docker is widely used for building and testing the Squid server in a containerized environment:
Docker commands in the script sections of jobs include
docker login, docker build,
docker pull, docker tag and
docker push, which log into Docker Hub, build images, pull
images, tag images, and push images, respectively.
The Docker --build-arg flag is used to pass the
Squid version to the Docker build command, influencing the Squid
server’s version in the Docker image.
Docker images are named and tagged in a detailed manner,
distinguishing different versions and platforms (amd64 or arm). The tag
naming is related to environment variables with a naming scheme of
${HUB_REGISTRY_IMAGE}:${SQUID_VERSION}-${PLATFORM}.
Dockfile linter is used to check for security vulnerabilities and enforce best practices on Dockerfiles in the project.
Overall, Docker plays a vital role in implementing the Continous Integration/Continuous Delivery pipeline in this project.