cipd: Add -tag option to 'create' and 'pkg-register' subcomands.

go/src/infra/tools/cipd/common.go

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package cipd
 
 import (
         "encoding/json"
         "fmt"
         "io"
         "io/ioutil"
         "regexp"
+        "strings"
 
         "infra/libs/build"
 )
 
 // Name of the directory inside the package reserved for cipd stuff.
 const packageServiceDir = ".cipdpkg"
 
 // Name of the directory inside an installation root reserved for cipd stuff.
 const siteServiceDir = ".cipd"
 
-// packageNameRe is a Regular expression for a package name: <word>/<word/<word>
+// packageNameRe is a regular expression for a package name: <word>/<word/<word>
 // Package names must be lower case.
 var packageNameRe = regexp.MustCompile(`^([a-z0-9_\-]+/)*[a-z0-9_\-]+$`)
 
+// instanceTagKeyRe is a regular expression for a tag key.
+var instanceTagKeyRe = regexp.MustCompile(`^[a-z0-9_\-]+$`)
+
 // Name of the manifest file inside the package.
 const manifestName = packageServiceDir + "/manifest.json"
 
 // Format version to write to the manifest file.
 const manifestFormatVersion = "1"
 
 // Manifest defines structure of manifest.json file.
 type Manifest struct {
         FormatVersion string `json:"format_version"`
         PackageName   string `json:"package_name"`
@@ skipping 14 matching lines @@
                 return fmt.Errorf("Not a valid package instance ID \"%s\": not 40 bytes", s)
         }
         for _, c := range s {
                 if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'f')) {
                         return fmt.Errorf("Not a valid package instance ID \"%s\": wrong char %c", s, c)
                 }
         }
         return nil
 }
 
+// ValidateInstanceTag returns error if a string doesn't look like a valid tag.
+func ValidateInstanceTag(t string) error {
+        chunks := strings.SplitN(t, ":", 2)
+        if len(chunks) != 2 {
+                return fmt.Errorf("The string %q doesn't look like a tag (a key:value pair)", t)
+        }
+        if len(t) > 400 {
+                return fmt.Errorf("The tag is too long: %q", t)
+        }
+        if !instanceTagKeyRe.MatchString(chunks[0]) {
+                return fmt.Errorf("Invalid tag key in %q. Should be a lowercase word.", t)
+        }
+        return nil
+}
+
 // DefaultServiceURL returns URL to a backend to use by default.
 func DefaultServiceURL() string {
         if build.ReleaseBuild {
                 return "https://chrome-infra-packages.appspot.com"
         }
         return "https://chrome-infra-packages-dev.appspot.com"
 }
 
 // readManifest reads and decodes manifest JSON from io.Reader.
 func readManifest(r io.Reader) (Manifest, error) {
@@ skipping 19 matching lines @@
         return err
 }
 
 // userAgent returns user agent string to send with each request.
 func userAgent() string {
         if build.ReleaseBuild {
                 return "cipd 1.0 release"
         }
         return "cipd 1.0 testing"
 }