Use Github Actions Cache to make workflows faster

[stefanleminh]

Currently neither Docker-Containers, no mvn or npm dependencies get cached. This results in relatively long build-times in Github Actions, especially with Cypress building the entire docker-compose infrastructure and the UI building the UI and the webcomponents.

Fortunately, Github Actions provide a way to cache these artifacts. This should be implemented in this ticket.

[ghost]

We might not need additional caching libraries for this - because we have a multistage building process for the docker images we may use the caching functionality of Docker itself, to skip the steps of downloading the dependencies each time we execute a build, by simply modifying the Dockerfiles.

A reference for maven: https://www.baeldung.com/ops/docker-cache-maven-dependencies

[ghost]

Quick note - although the solution works locally, because of the caching of the locally ran instance of Docker, it doesn't for github. Most probably they don't leave any dangling artefacts after completion of each build so they could save space(or creating a temporary vm for the build only, which is destroyed after completion). Carrying on with trying the original idea of using caching of artifacts from Stefan.

[ghost]

Adding changes with caching of Docker layers on github actions + local caching. Some results:

Cypress Worst case scenario(changes in poms for marketplace service, admin-ui and authentication service) - 9:43 Non-dependency changes for marketplace service, admin-ui and authentication service + cache - 8:50 - Times are actually most dependent on admin-ui. There Vaadin library is at fault, because it needs the compiled java project to decide which dependencies to download No changes for marketplace service, admin-ui or authentication service + cache - 5:50

Frontend + deploy: Worst-case scenario(changes to package.json of main project or any webcomponent + deployment) - 10:00 Non dependency changes + cache - 8:20

Marketplace service + deploy: Worse case scenario(changes in pom.xml + deployment) - 4:47 Non dependency changes + cache - 2:00

Quick notes for Github caching as of time of writing:

• Cache files are deleted after 7 days of no access to them;
• Cache files are shared between branches;
• There must be a separate cache file for each image;
• No manual way to clear caches;
• There isn't caching for docker-compose and that's why changed cypress to parallel build of required images(different job for each image) and using a docker-compose file, which references the images by name:tag combination;

Some links for future docs when wiki is up:

• General info about Git cache
• Docker build local cahcing
• Caching docker layers on github actions
• Exporting docker images between jobs
• Caching maven dependencies on docker

[fingeririna]

Dokumentation in wiki will be done as soon as wiki is available.

[ghost]

Link to technical document on akros wiki: https://wiki.akros.ch/display/TO/Docker+layers+and+Github+Actions+caching