cmd/benchsave: command-line tool for uploading benchmark results

Change-Id: I060d45ac3b487900ab8315978fe89ab576c571b7
Reviewed-on: https://go-review.googlesource.com/35053Reviewed-by: Russ Cox <rsc@golang.org>

cmd/benchsave/benchsave.go

+// Copyright 2017 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Benchsave uploads benchmark results to a storage server.
+//
+// Usage:
+//
+//	benchsave [-server https://server.org] a.txt [b.txt ...]
+//
+// Each input file should contain the output from one or more runs of
+// ``go test -bench'', or another tool which uses the same format.
+//
+// benchsave will upload the input files to the specified server and
+// print a URL where they can be viewed.
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"mime/multipart"
+	"net/http"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+var (
+	server  = flag.String("server", "https://perfdata.golang.org", "perfdata server to upload benchmarks to")
+	verbose = flag.Bool("v", false, "verbose")
+)
+
+type uploadStatus struct {
+	// UploadID is the upload ID assigned to the upload.
+	UploadID string `json:"uploadid"`
+	// FileIDs is the list of file IDs assigned to the files in the upload.
+	FileIDs []string `json:"fileids"`
+	// ViewURL is a server-supplied URL to view the results.
+	ViewURL string `json:"viewurl"`
+}
+
+// writeOneFile reads name and writes it to mpw.
+func writeOneFile(mpw *multipart.Writer, name string) {
+	w, err := mpw.CreateFormFile("file", filepath.Base(name))
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Writing upload failed: %v\n", err)
+		os.Exit(1)
+	}
+	f, err := os.Open(name)
+	if err != nil {
+		fmt.Fprint(os.Stderr, err)
+		mpw.WriteField("abort", "1")
+		// TODO(quentin): Wait until the abort field is written before exiting.
+		os.Exit(1)
+	}
+	defer f.Close()
+
+	if _, err := io.Copy(w, f); err != nil {
+		fmt.Fprintf(os.Stderr, "Writing upload failed: %v", err)
+		os.Exit(1)
+	}
+}
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `Usage of %s:
+%s [flags] file...
+`, os.Args[0], os.Args[0])
+	flag.PrintDefaults()
+	os.Exit(2)
+}
+
+func main() {
+	log.SetPrefix("benchsave: ")
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+
+	// TODO(quentin): Authentication
+
+	files := flag.Args()
+	if len(files) == 0 {
+		log.Fatal("no files to upload")
+	}
+
+	pr, pw := io.Pipe()
+	mpw := multipart.NewWriter(pw)
+
+	go func() {
+		defer pw.Close()
+		defer mpw.Close()
+
+		for _, name := range files {
+			writeOneFile(mpw, name)
+		}
+	}()
+
+	start := time.Now()
+
+	resp, err := http.Post(*server+"/upload", mpw.FormDataContentType(), pr)
+	if err != nil {
+		log.Fatalf("upload failed: %v\n", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		log.Printf("upload failed: %v\n", resp.Status)
+		io.Copy(os.Stderr, resp.Body)
+		os.Exit(1)
+	}
+
+	status := &uploadStatus{}
+	if err := json.NewDecoder(resp.Body).Decode(status); err != nil {
+		log.Fatalf("cannot parse upload response: %v\n", err)
+	}
+
+	if *verbose {
+		s := ""
+		if len(files) != 1 {
+			s = "s"
+		}
+		log.Printf("%d file%s uploaded in %.2f seconds.\n", len(files), s, time.Since(start).Seconds())
+	}
+	if status.ViewURL != "" {
+		fmt.Printf("%s\n", status.ViewURL)
+	}
+	// TODO(quentin): Print benchstat-style output, either computed client-side or fetched from a server.
+}