Update bulidbucket client

buildbucket/client/cmd/buildbucket/base_command.go

Index: buildbucket/client/cmd/buildbucket/base_command.go
diff --git a/buildbucket/client/cmd/buildbucket/base_command.go b/buildbucket/client/cmd/buildbucket/base_command.go
new file mode 100644
index 0000000000000000000000000000000000000000..8388849b0f16ea2b0334e5a0c27358df10182df4
--- /dev/null
+++ b/buildbucket/client/cmd/buildbucket/base_command.go
@@ -0,0 +1,123 @@
+// Copyright 2016 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 (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/maruel/subcommands"
+	"golang.org/x/net/context"
+
+	"net/url"
+
+	"github.com/luci/luci-go/common/auth"
+	"github.com/luci/luci-go/common/lhttp"
+	"github.com/luci/luci-go/common/logging"
+)
+
+type baseCommandRun struct {
+	subcommands.CommandRunBase
+	serviceAccountJSONPath string
+	host                   string
+}
+
+func (r *baseCommandRun) SetDefaultFlags() {
+	r.Flags.StringVar(
+		&r.serviceAccountJSONPath,
+		"service-account-json",
+		"",
+		"path to service account json file.")
+	r.Flags.StringVar(
+		&r.host,
+		"host",
+		"cr-buildbucket.appspot.com",
+		"host for the buildbucket service instance.")
+}
+
+func (r *baseCommandRun) createClient(ctx context.Context) (*client, error) {
+	if r.host == "" {
+		return nil, fmt.Errorf("a host for the buildbucket service must be provided")
+	}
+	if strings.ContainsRune(r.host, '/') {
+		return nil, fmt.Errorf("invalid host %q", r.host)
+	}
+
+	loginMode := auth.OptionalLogin
+	if r.serviceAccountJSONPath != "" {
+		// if service account is specified, the request MUST be authenticated
+		// otherwise it is optional.
+		loginMode = auth.SilentLogin
+	}
+	authenticator := auth.NewAuthenticator(ctx, loginMode, auth.Options{
+		ServiceAccountJSONPath: r.serviceAccountJSONPath,
+	})
+
+	httpClient, err := authenticator.Client()
+	if err != nil {
+		return nil, err
+	}
+
+	protocol := "https"
+	if lhttp.IsLocalHost(r.host) {
+		protocol = "http"
+	}
+
+	return &client{
+		HTTP: httpClient,
+		baseURL: &url.URL{
+			Scheme: protocol,
+			Host:   r.host,
+			Path:   "/api/buildbucket/v1/",
+		},
+	}, nil
+}
+
+func (r *baseCommandRun) done(ctx context.Context, err error) int {
+	if err != nil {
+		logging.Errorf(ctx, "%s", err)
+		return 1
+	}
+	return 0
+}
+
+// callAndDone makes a buildbucket API call, prints error or response, and returns exit code.
+func (r *baseCommandRun) callAndDone(ctx context.Context, method, relURL string, body interface{}) int {
+	client, err := r.createClient(ctx)
+	if err != nil {
+		return r.done(ctx, err)
+	}
+
+	res, err := client.call(ctx, method, relURL, body)
+	if err != nil {
+		return r.done(ctx, err)
+	}
+
+	fmt.Printf("%s\n", res)
+	return 0
+}
+
+// buildIDArg can be embedded into a subcommand that accepts a build ID.
+type buildIDArg struct {
+	buildID int64
+}
+
+func (a *buildIDArg) parseArgs(args []string) error {
+	if len(args) < 1 {
+		return fmt.Errorf("missing parameter: <Build ID>")
+	}
+	if len(args) > 1 {
+		return fmt.Errorf("unexpected arguments: %s", args[1:])
+	}
+
+	id, err := strconv.ParseInt(args[0], 10, 64)
+	if err != nil {
+		return fmt.Errorf("expected a build id (int64), got %s: %s", args[0], err)
+	}
+
+	a.buildID = id
+	return nil
+}