#Lab Solution

The second part of the GitHub build uses the latest Docker Compose file:

• release.yml uses different image tags, with the RELEASE environment variable but not the BUILD_NUMBER variable the main Compose file uses

When you merge in the latest file it will build images with the tag 21.05, which is the version for this release of the app.

Consumers can use 21.05 to get the current build for this release, or e.g. 21.05-39 to get a specific build:

docker pull courselabs/rng-api:21.05

docker image ls courselabs/rng-api

Be careful with the word alias here. The workflow builds the two tags in two separate docker compose build runs, so they end up as separate images even when the source is identical - compare them and the digests differ:

docker manifest inspect courselabs/rng-api:21.05

docker manifest inspect courselabs/rng-api:21.05-39

What matters to a consumer is the promise each tag makes: 21.05 always gives you the current build of that release, and 21.05-39 always gives you that exact build. With the next release the 21.05 tag moves on; the numbered tag never does.

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