config: add env_merge support to containers.conf

[jiwahn]

Allow users to set default env_merge values in containers.conf. Intended to work the same as the --env-merge CLI option.

• Related: Add env_merge to containers.conf podman#28410

Changes

• Add EnvMerge []string field to ContainersConfig struct (config.go)
• Set default value to empty slice (default.go)
• Add commented-out env_merge = [] entry to containers.conf template
• Add documentation to containers.conf.5.md

[TomSweeneyRedHat]

restarted failed tests, not related to the change.
IDK if possible, but a test would be nice if one could be created.
@Luap99 WDYT?

[jankaluza]

I think adding test into common/pkg/config/config_local_test.go would be great. I did not explore it a lot, but maybe adding env_merge into some testdata in common/pkg/config/testdata/containers_default and verifying it is loaded properly in config_local_test.go would be enough.

You could also test append=true with modules_test.go. It already does that with env.

[Luap99]

as for a tests here is an example commit b2db08d

[jiwahn]

Thanks guys for the comments and the helpful example. I have updated the changes.

changes

• Changed ContainersConfig.EnvMerge from []string to configfile.Slice so env_merge supports string-array features such as append=true.
• Updated the default EnvMerge value to use configfile.Slice{}.
• Added a config parsing test to verify that env_merge is loaded from containers_default.conf.
• Extended the modules test to verify that env_merge supports append=true across module configs.

result

go test ./common/pkg/config -ginkgo.focus="Config Modules"
go test ./common/pkg/config -ginkgo.focus="should parse env_merge from config file"
ok      go.podman.io/common/pkg/config  0.006s
ok      go.podman.io/common/pkg/config  0.007s

[Luap99]

please squash the commits into a single one

[jiwahn]

of course, rebased