sqlc-gen-json

A sqlc plugin that writes the GenerateRequest sqlc would have passed to your codegen plugin out as a single JSON file.

Useful for:

• Debugging plugin pipelines — see exactly what schema, queries, settings, and plugin options sqlc parsed before invoking your generator.
• Prototyping new plugins — capture a real request, then iterate on a generator script offline against the saved JSON.
• Schema snapshots — keep a versioned JSON view of your database catalog alongside the SQL.

Installation

The plugin ships as a WASM artifact. Reference it from sqlc.yaml with the release URL and its sha256:

version: "2"
plugins:
  - name: json
    wasm:
      url: https://github.com/sqlc-contrib/sqlc-gen-json/releases/download/v0.1.0/sqlc-gen-json.wasm
      sha256: <sha256 from the release assets>

Both the .wasm and a .wasm.sha256 sidecar are published with each release.

Configuration

sql:
  - engine: postgresql
    schema: db/schema.sql
    queries: db/queries.sql
    codegen:
      - plugin: json
        out: ./gen
        options:
          filename: generate_request.json # optional
          indent: "  " # optional; "-" disables indent
          use_proto_names: false # optional
          emit_defaults: false # optional

Option	Type	Default	Description
filename	string	generate_request.json	Name of the emitted file.
indent	string	" " (two spaces)	Per-level indent string passed to protojson. Use the sentinel - to emit compact (single-line) JSON.
use_proto_names	boolean	false	When true, emit field names from the proto descriptor (snake_case) instead of protojson's default JSON names.
emit_defaults	boolean	false	When true, include scalar fields whose value is the zero value.

Unknown top-level options are rejected.

Output

The output is the full plugin.GenerateRequest from plugin-sdk-go serialized via protojson. A trimmed example for a single-table schema:

{
  "settings": { "engine": "postgresql" },
  "catalog": {
    "defaultSchema": "public",
    "schemas": [
      {
        "name": "public",
        "tables": [
          {
            "rel": { "schema": "public", "name": "users" },
            "columns": [
              { "name": "id", "type": { "name": "int4" }, "notNull": true },
              { "name": "email", "type": { "name": "text" }, "notNull": true }
            ]
          }
        ]
      }
    ]
  },
  "queries": [{ "name": "GetUser", "cmd": ":one" }],
  "sqlc_version": "v1.30.0"
}

Note that plugin-sdk-go's proto descriptors do not consistently set json_name, so default output mixes camelCase (e.g. defaultSchema, notNull) and snake_case (e.g. sqlc_version). Set use_proto_names: true to force snake_case across the board.

Caveats

• Output is not byte-stable across runs. protojson.Marshal intentionally injects random whitespace to discourage byte-stable diffing. For diffs, use a JSON-aware tool (jq -S, diff <(jq -S . a) <(jq -S . b), etc.) rather than direct text comparison.
• No formatter_cmd. sqlc plugins cannot spawn subprocesses. If you want canonical formatting, run jq -S . generate_request.json | sponge generate_request.json (or similar) as a post-step.

Development

nix develop
go tool ginkgo run -r -coverprofile=coverage.out -covermode=atomic ./...

Build the WASM artifact locally:

nix build .#wasm
sha256sum result/bin/sqlc-gen-json.wasm

A native binary build is also exposed for convenience (used by the integration tests via gexec.Build):

nix build .       # default == native build
./result/bin/sqlc-gen-json --help

License

MIT