Generate OpenAPI v2 and v3 specs (#146)

Expose the OpenAPI docs generated in our main API repo

Makefile

@@ -5,7 +5,7 @@ all: install test
 install: grpc-install mockgen-install goimports-install update-proto
 
 # Compile proto files.
-proto: grpc goimports proxy grpc-mock copyright
+proto: http-api-docs grpc goimports proxy grpc-mock copyright
 
 # Update submodule and compile proto files.
 update-proto: update-proto-submodule proto update-dependencies gomodtidy
@@ -32,6 +32,9 @@ PROTO_IMPORTS = \
 	-I=$(PROTO_ROOT)
 PROTO_PATHS = paths=source_relative:$(PROTO_OUT)
 
+OAPI_ROOT := $(PROTO_ROOT)/openapi
+OAPI_OUT := temporalproto/openapi
+
 $(PROTO_OUT):
 	mkdir $(PROTO_OUT)
 
@@ -41,7 +44,7 @@ update-proto-submodule:
 	git -c protocol.file.allow=always submodule update --init --force --remote $(PROTO_ROOT)
 
 ##### Compile proto files for go #####
-grpc: go-grpc copy-helpers
+grpc: http-api-docs go-grpc copy-helpers
 
 # Only install helper when its source has changed
 HELPER_FILES = $(shell find ./cmd/protoc-gen-go-helpers)
@@ -65,6 +68,13 @@ go-grpc: clean .go-helpers-installed $(PROTO_OUT)
 
 	mv -f $(PROTO_OUT)/temporal/api/* $(PROTO_OUT) && rm -rf $(PROTO_OUT)/temporal
 
+http-api-docs: go-grpc
+	go run cmd/encode-openapi-spec/main.go \
+		-v2=$(OAPI_ROOT)/openapiv2.json \
+		-v2-out=$(OAPI_OUT)/openapiv2.go \
+		-v3=$(OAPI_ROOT)/openapiv3.yaml \
+		-v3-out=$(OAPI_OUT)/openapiv3.go
+
 # Copy the payload helpers
 copy-helpers:
 	chmod +w $(PROTO_OUT)/common/v1/payload_json.go 2>/dev/null || true

cmd/encode-openapi-spec/main.go

@@ -0,0 +1,109 @@
+// The MIT License
+//
+// Copyright (c) 2022 Temporal Technologies Inc.  All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"flag"
+	"fmt"
+	"go/format"
+	"html/template"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+type templateInput struct {
+	Version int
+	Format  string
+	Spec    string
+}
+
+const tmpl = `package openapi
+
+// OpenAPIV{{.Version}}{{.Format}}Spec contains a gzip-compressed {{.Format}} file specifying the Temporal HTTP API
+var OpenAPIV{{.Version}}{{.Format}}Spec = {{.Spec}}`
+
+func die(msg string, args ...any) {
+	fmt.Fprintf(os.Stderr, msg+"\n", args...)
+	os.Exit(1)
+}
+
+func prepareSpec(version int, input, output string) {
+	extension := strings.TrimPrefix(filepath.Ext(input), ".")
+	f, err := os.Open(input)
+	if err != nil {
+		die("Failed to open spec file %q: %v", input, err)
+	}
+	defer f.Close()
+
+	var b bytes.Buffer
+	w := gzip.NewWriter(&b)
+	if _, err := io.Copy(w, f); err != nil {
+		die("Failed to compress v%d spec: %s", version, err)
+	}
+	if err := w.Close(); err != nil {
+		die("Failed to compress v%d spec: %s", version, err)
+	}
+
+	var src bytes.Buffer
+	t := template.Must(template.New("spec").Parse(tmpl))
+	t.Execute(&src, templateInput{
+		Version: version,
+		Format:  strings.ToTitle(extension),
+		Spec:    fmt.Sprintf("%#v", b.Bytes()),
+	})
+
+	fmtd, err := format.Source(src.Bytes())
+	if err != nil {
+		die("Failed to format generated v%d code: %s", version, err)
+	}
+
+	out, err := os.Create(output)
+	if err != nil {
+		die("Failed to open %q: %s", output, err)
+	}
+	defer out.Close()
+	if _, err := out.Write(fmtd); err != nil {
+		die("Failed to write v%d code: %s", version, err)
+	}
+
+}
+
+func main() {
+	var v2Path, v3Path, v2Out, v3Out string
+	flag.StringVar(&v2Path, "v2", "", "The path to the OpenAPI v2 spec file. Required.")
+	flag.StringVar(&v3Path, "v3", "", "The path to the OpenAPI v3 spec file. Required.")
+	flag.StringVar(&v2Out, "v2-out", "", "The path to the v2 output file. Required.")
+	flag.StringVar(&v3Out, "v3-out", "", "The path to the v3 output file. Required.")
+	flag.Parse()
+	if v2Path == "" || v3Path == "" || v2Out == "" || v3Out == "" {
+		flag.Usage()
+		os.Exit(127)
+	}
+
+	prepareSpec(2, v2Path, v2Out)
+	prepareSpec(3, v3Path, v3Out)
+}

temporalproto/openapi/payload_description.txt

@@ -0,0 +1,2 @@
+Arbitrary payload data in an unconstrained format.
+This may be activity input parameters, a workflow result, a memo, etc.