client/isolate: add --dump_json support to exparchive

client/cmd/isolate/exp_archive.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package main
 
 import (
         "context"
         "encoding/json"
         "errors"
         "fmt"
         "io/ioutil"
         "log"
         "os"
         "path/filepath"
+        "strings"
 
         "time"
 
         humanize "github.com/dustin/go-humanize"
 
         "github.com/golang/protobuf/proto"
         "github.com/luci/luci-go/client/isolate"
         "github.com/luci/luci-go/common/eventlog"
         logpb "github.com/luci/luci-go/common/eventlog/proto"
         "github.com/luci/luci-go/common/isolated"
@@ skipping 16 matching lines @@
 )
 
 var cmdExpArchive = &subcommands.Command{
         UsageLine: "exparchive <options>",
         ShortDesc: "EXPERIMENTAL parses a .isolate file to create a .isolated file, and uploads it and all referenced files to an isolate server",
         LongDesc:  "All the files listed in the .isolated file are put in the isolate server cache. Small files are combined together in a tar archive before uploading.",
         CommandRun: func() subcommands.CommandRun {
                 c := &expArchiveRun{}
                 c.commonServerFlags.Init()
                 c.isolateFlags.Init(&c.Flags)
+                c.Flags.StringVar(&c.dumpJSON, "dump-json", "",
+                        "Write isolated digests of archived trees to this file as JSON")
                 return c
         },
 }
 
 // expArchiveRun contains the logic for the experimental archive subcommand.
 // It implements subcommand.CommandRun
 type expArchiveRun struct {
         commonServerFlags // Provides the GetFlags method.
         isolateFlags      isolateFlags
+        dumpJSON          string
 }
 
 // Item represents a file or symlink referenced by an isolate file.
 type Item struct {
         Path    string
         RelPath string
         Size    int64
         Mode    os.FileMode
 
         Digest isolated.HexDigest
@@ skipping 175 matching lines @@
         if err := uploader.Close(); err != nil {
                 return err
         }
 
         // Write the isolated file, and emit its digest to stdout.
         if err := ioutil.WriteFile(archiveOpts.Isolated, isolJSON, 0644); err != nil {
                 return err
         }
         fmt.Printf("%s\t%s\n", isolItem.Digest, filepath.Base(archiveOpts.Isolated))
 
+        // Optionally, write the digest of the isolated file as JSON (in the same
+        // format as batch_archive).
+        if c.dumpJSON != "" {
+                // The name is the base name of the isolated file, extension stripped.
+                name := filepath.Base(archiveOpts.Isolated)
+                if i := strings.LastIndex(name, "."); i != -1 {
+                        name = name[:i]
+                }
+                j, err := json.Marshal(map[string]isolated.HexDigest{
+                        name: isolItem.Digest,
+                })
+                if err != nil {
+                        return err
+                }
+                if err := ioutil.WriteFile(c.dumpJSON, j, 0644); err != nil {
+                        return err
+                }
+        }
+
         end := time.Now()
 
         if endpoint := eventlogEndpoint(c.isolateFlags.EventlogEndpoint); endpoint != "" {
                 logger := eventlog.NewClient(ctx, endpoint)
 
                 // TODO(mcgreevy): fill out more stats in archiveDetails.
                 archiveDetails := &logpb.IsolateClientEvent_ArchiveDetails{
                         HitCount:    proto.Int64(int64(checker.Hit.Count)),
                         MissCount:   proto.Int64(int64(checker.Miss.Count)),
                         HitBytes:    &checker.Hit.Bytes,
@@ skipping 70 matching lines @@
 func eventlogEndpoint(endpointFlag string) string {
         switch endpointFlag {
         case "test":
                 return eventlog.TestEndpoint
         case "prod":
                 return eventlog.ProdEndpoint
         default:
                 return endpointFlag
         }
 }