[FEATURE REQUEST] Add GO templating capabilities to images and/or list commands
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Description
Description
There are situations where I'd like to down all projects and this requires access to all project names in a machine readable format.
Given that several docker CLI/compose commands provide templating capabilities with the --format flag I'd expect to solve this with:
docker compose ls --format '{{.Name}}' | xargs -I{} docker compose -p {} down
But docker compose ls --format <format> only offers json or table format therefore it's only possible to get project names using external applications.
If using table format you'd have to hack a shell pipeline.
docker compose ls | tail -n +2 | awk '{print $1}' | xargs -I{} docker compose -p {} down
If using json format, even though json is machine readable, it requires you to pipe to a parser, such as jq, which very likely it's not available.
docker compose ls --format json | jq '.[].Name' | xargs -I{} docker compose -p {} down
The docker CLI and compose already provide GO Templates formatting for several commands such as:
docker ps --format <TEMPLATE>docker images --format <TEMPLATE>docker stats --format <TEMPLATE>docker compose ps --format <TEMPLATE>
The list goes on.
In compose there is compose images and compose ls which not only are not able to handle Templates but they also print JSON in a different way than the ones that support Templates.
The commands that have support print each object as a separate JSON in a different line, while the ones that don't print a JSON list in a single line:
docker images --format json
# {"Containers":"N/A","CreatedAt":"2014-07-19 04:02:32 -0300 -03","CreatedSince":"10 years ago","Digest":"\u003cnone\u003e","ID":"350b164e7ae1","Repository":"gcr.io/google-containers/pause","SharedSize":"N/A","Size":"240kB","Tag":"latest","UniqueSize":"N/A","VirtualSize":"239.8kB"}
# {"Containers":"N/A","CreatedAt":"1979-12-31 21:00:00 -0300 -03","CreatedSince":"45 years ago","Digest":"\u003cnone\u003e","ID":"f576b2d0af25","Repository":"test","SharedSize":"N/A","Size":"2.06GB","Tag":"latest","UniqueSize":"N/A","VirtualSize":"2.056GB"}
docker compose images --format json
# [{"ID":"sha256:350b164e7ae1dcddeffadd65c76226c9b6dc5553f5179153fb0e36b78f2a5e06","ContainerName":"test_1-compose_test-1","Repository":"gcr.io/google-containers/pause","Tag":"latest","Size":239840,"LastTagTime":"0001-01-01T00:00:00Z"},{"ID":"sha256:350b164e7ae1dcddeffadd65c76226c9b6dc5553f5179153fb0e36b78f2a5e06","ContainerName":"test_1-compose_test_2-1","Repository":"gcr.io/google-containers/pause","Tag":"latest","Size":239840,"LastTagTime":"0001-01-01T00:00:00Z"}]
Implementing templating capabilities for these commands would change the output format but only to conform with already existing behavior.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the docker compose ls and docker compose images entry points and compare their current --format json behavior with commands such as docker ps and docker images. Done means both commands accept Go templates and produce output consistent with existing template-capable commands, while preserving the requested machine-readable behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- docker-compose, go
- Domain
- cli
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100