openapi-codegen parses an OpenAPI 3.x specification and generates idiomatic Go code — types, an HTTP client, an HTTP server scaffold, and tests.

Generated code has a reputation for being obviously generated. This module tries hard not to earn it: output is run through goimports and gofumpt, names are converted to Go conventions rather than transliterated, and the emitted types are the ones you would have declared by hand.

Getting there depends on the specification being in good shape first, which is why this module doesn't work from the raw document. It normalizes the spec through the rest of the family before generating anything:

1. Load the specification, and any recorded HTTP interactions
2. Validate it
3. Flatten — every meaningful type gets a name, so it can become a named Go type
4. Compress — duplicate schemas collapse, so the same shape doesn't become five Go types
5. Build an intermediate representation, resolving schemas to Go types
6. Match recorded interactions to operations, for round-trip tests
7. Render and format the output

• types — structs, enums, and type aliases for all referenced schemas
• client — typed HTTP client with per-operation methods
• server — http.Handler-based server scaffold
• tests — round-trip and cassette-backed tests, generated from recorded traffic
• JavaScript client — optional api.js alongside the Go output

Identifiers are sanitized into valid, idiomatic Go: leading digits are spelled out, punctuation is stripped, acronyms are preserved, and names that would collide with the error interface or a Go keyword are renamed.

go get -tool github.com/MarkRosemaker/openapi-codegen/cmd/openapi-codegen

or

go get github.com/MarkRosemaker/openapi-codegen

openapi-codegen -spec openapi.json -out ./gen -pkg mypkg -client

At least one of -client, -server, or -js is required. Types are generated automatically whenever a client or server is, and client tests whenever a client is.

It can also be used as a library:

import "github.com/MarkRosemaker/openapi-codegen"

err := codegen.Generate(codegen.Config{
    SpecPath:    "api/openapi.json",
    OutputDir:   "pkg/mypkg",
    PackageName: "mypkg",
})

Config accepts an already-parsed *openapi.Document instead of SpecPath, and an afero.Fs instead of OutputDir, so generation can run entirely in memory.

This module sits at the end of the pipeline. If you have no specification to start from, openapi-enrich can build one from recorded traffic — and the same recordings then become the generated client's tests.

• Go Reference: The Go reference documentation for the openapi-codegen package.
• Go Report Card: Check the code quality report.

If you have any contributions to make, please submit a pull request or open an issue on the GitHub repository.

This project is licensed under the Apache 2.0 License.