github.com/kishieel/couchdb-query-server-go

CouchDB Query Server Go

The CouchDB Query Server Go is a Go implementation of the CouchDB Query Server protocol for CouchDB 3.3.0 or later. It is a drop-in replacement for the JavaScript implementation that ships with CouchDB.

Usage

To use the CouchDB Query Server Go, you need to add couchgo executable to the CouchDB and add the following environment variable:

export COUCHDB_QUERY_SERVER_GO=/path/to/couchgo

Then you can write your design documents in Go and use them in CouchDB.

{
  "_id": "_design/example",
  "views": {
    "view-1": {
      "map": "func Map(args couchgo.MapInput) couchgo.MapOutput {\n\tout := make([][2]any, 0)\n\tout = append(out, [2]any{args.Doc[\"_id\"], args.Doc[\"type\"]})\n\n\treturn out\n}"
    },
    "view-2": {
      "map": "func Map(args couchgo.MapInput) couchgo.MapOutput {  \n    out := couchgo.MapOutput{}\n\tout = append(out, [2]interface{}{args.Doc[\"_id\"], 1})\n\tout = append(out, [2]interface{}{args.Doc[\"_id\"], 2})\n\tout = append(out, [2]interface{}{args.Doc[\"_id\"], 3})\n\t\n\treturn out\n}",
      "reduce": "func Reduce(args couchgo.ReduceInput) couchgo.ReduceOutput {\n\tout := 0.0\n\n\tfor _, value := range args.Values {\n\t\tout += value.(float64)\n\t}\n\n\treturn out\n}"
    }
  },
  "filters": {
    "filter-1": "func Filter(args couchgo.FilterInput) couchgo.FilterOutput {\n\treturn args.Doc[\"type\"] == \"post\"\n}"
  },
  "updates": {
    "update-1": "func Update(args couchgo.UpdateInput) couchgo.UpdateOutput {\n\targs.Doc[\"updated\"] = true\n\treturn couchgo.UpdateOutput{args.Doc, \"ok\"}\n}"
  },
  "rewrites": "func Rewrite(args couchgo.RewriteInput) couchgo.RewriteOutput {\n\treturn couchgo.RewriteOutput{\n\t\tHeaders: map[string]string{\"Location\": \"https://example.com\"},\n\t\tCode:    302,\n\t}\n}",
  "validate_doc_update": "func Validate(args couchgo.ValidateInput) couchgo.ValidateOutput {\n\treturn nil\n}",
  "language": "go"
}

Caveats

The Couchdb Query Server Go is a work in progress and is not yet feature complete. It implements only minimal functionality without commands that are marked as deprecated in the CouchDB documentation.

Notes

go build -o ./bin/couchgo ./lib

Benchmarks

Test	CouchGO!	CouchJS	Boost
Indexing (100k docs)	141.713s	421.529s	2.97x
Reducing (100k docs)	7672ms	15642ms	2.04x
Filtering (100k docs)	28.928s	80.594s	2.79x
Updating (1k docs)	7.742s	9.661s	1.25x