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manifest: the shared vocabulary

The github.com/yohimik/dispat/pkg/manifest package provides the vocabulary shared by the manifest reader and the manifest writer. This ensures both halves never drift apart. They range over the same format list, spell dependency kinds the same way, and agree exactly on what a Docker reference is.

The package contains models, pure functions, and parsers. It has no dependencies and performs no I/O. Nothing here touches your filesystem.

go get github.com/yohimik/dispat/pkg/manifest

The surface, by concern​

Formats. The Format type names each of the thirty-five recognised manifest formats, and Formats provides the canonical list both halves prove they cover. FormatOf maps a file name onto its format. IsRequirementsFile matches requirements files by whole words, and IsDockerfile matches Dockerfile, Dockerfile.dev, api.Dockerfile, and Containerfile while excluding prose extensions.

Kinds. The Kind type identifies the dependency field a declaration came from. It has four constants spelled like the fields themselves, with the zero value standing for plain dependencies. ParseKind reads a spelling from a configuration file or a command line, and it accepts "dependencies" as the long form of the zero value.

Names. The NameWords function splits a file's base name into words. NormalizePyName applies PEP 503 identically on both sides. This normalization keeps Acme_Core and acme-core recognized as a single package.

Docker. ParseImageRef reads an image reference into a repository, tag, and digest, recording the tag's byte span. ValidTag provides the registry tag grammar, while DockerfileRefs walks a Dockerfile's FROM, COPY --from, and RUN --mount instructions with stage-alias scoping. ComposeService and ComposeIdentity decide which service's image names a compose file, and these parsers live here so both halves get byte-identical offsets.

In use​

manifest.FormatOf("Dockerfile.dev")                 // FormatDockerfile, true
manifest.KindDevDependencies                        // the four dependency kinds, spelled like the fields
manifest.ParseKind("dependencies")                  // KindDependencies, true
manifest.IsRequirementsFile("requirements-dev.txt") // true
manifest.NormalizePyName("Acme_Core")               // "acme-core" (PEP 503)
manifest.ParseImageRef("ghcr.io/acme/api:1.2.0")    // repository, tag and the tag's span

The byte span is the detail that makes the reader and writer work together. The reader records where a version sits, and the writer splices exactly that range. A rewrite changes only the version text and leaves everything around it untouched.

Further reading​