We scan this tool’s changelog a few times a day and keep the changes that would alter your agent’s next action: 14 since January 2026, each linked to its source.
daggerWhen using a Dagger Service as the image registry, pass it as `RegistryService` to `Container.From` or `Container.Publish`. This selects that service for the registry operation without starting unrelated services attached to the container.
_, err := dag.Container().WithNewFile("/hello.txt", "hello").Publish(ctx, "<registry-host>:5000/<image>:<tag>", dagger.ContainerPublishOpts{RegistryService: registry})When checking whether a container path exists, set `expand: true` to expand `$VAR` or `${VAR}` using the container’s environment variables. `expand` defaults to `false`.
query { container { exists(path: "/$VAR/foo", expand: true) } }When checking generated files for staleness in Dagger v0.21.0, run `dagger check`; it exposes a check for each `generate` function. Use `dagger check --no-generate` to list or run only explicitly marked checks.
dagger checkWhen a Dagger workspace needs reproducible selected lookups, run with `--lock live`, `--lock pinned`, or `--lock frozen` to control lookup resolution. Run `dagger lock update` to refresh recorded entries; in v0.21.0 it also creates `.dagger/lock` when missing.
dagger --lock live <command> [arguments...]When validating a repository, run `dagger check --failfast` to cancel remaining checks after the first failure.
dagger check --failfastWhen a Dagger module defines a service function marked with `@up` (or the SDK equivalent), run `dagger up` to start its services and expose their ports on the host. Configure `portMappings` when a toolchain service needs a different host port.
dagger upWhen running a Dagger workflow without progress dots, select the `logs` progress format. In v0.20.0, the documented CLI flag is `--progress=logs`.
dagger --progress=logs <command>When combining changesets from module functions, call `withChangeset` for one changeset or `withChangesets` for several. Choose a supported `onConflict` value when conflicts need handling; the plural method supports only `FAIL` and `FAIL_EARLY` in v0.19.11.
changeset.withChangeset(changes: <otherChangeset>, onConflict: <strategy>)When repository code generation is implemented as Dagger generator functions, mark each function with the SDK’s generate annotation and have it return a Changeset. Run `dagger generate` from the workspace to run generators and review and apply their combined changeset.
dagger generateWhen a Dockerfile build step needs SSH authentication, pass an SSH socket to `Directory.dockerBuild`; its `RUN --mount=type=ssh` instruction can then use that socket.
func (m *MyModule) DoDockerbuild(dir *dagger.Directory, sshSock *dagger.Socket) *dagger.Container {
return dir.DockerBuild(dagger.DirectoryDockerBuildOpts{SSH: sshSock})
}
dag then call do-dockerbuild --dir . --ssh-sock "$SSH_AUTH_SOCK"