feat(release): add automatic git tagging

Closes whyrusleeping#157

README.md

@@ -73,7 +73,7 @@ republish it, it would produce the *exact* same hash.
 
 ### package.json
 
-It should be noted that gx is meant to *work with* existing `package.json` files. If you are adding a package to gx that already has a `package.json` file in its root, gx will try and work with it. Any shared fields will have the same types, and any fields unique to gx will kept separate. 
+It should be noted that gx is meant to *work with* existing `package.json` files. If you are adding a package to gx that already has a `package.json` file in its root, gx will try and work with it. Any shared fields will have the same types, and any fields unique to gx will kept separate.
 
 E.g. A single `package.json` file could be used to serve both gx and another packaging tool, such as npm. Since gx is **Alpha Quality** there may be some exceptions to the above statements, if you notice one, please file an issue.
 
@@ -300,6 +300,9 @@ in your `package.json` as your `releaseCmd`. To get the above git commit flow,
 you can set it to: `git commit -a -m \"gx publish $VERSION\"` and gx will
 replace `$VERSION` with the newly changed version before executing the git
 commit.
+In addition to commiting, it will also publish a git tag, using the default command
+`git tag -a "v$VERSION" -m "gx release published as $HASH"`. To change the command you can set
+the `tagCmd` field to a command of your choosing.
 
 ### Ignoring files from a publish
 You can use a `.gxignore` file to make gx ignore certain files during a publish.

gxutil/pkgfile.go

@@ -21,6 +21,7 @@ type PackageBase struct {
 	Build           string        `json:"build,omitempty"`
 	Test            string        `json:"test,omitempty"`
 	ReleaseCmd      string        `json:"releaseCmd,omitempty"`
+	TagCmd          string        `json:"tagCmd,omitempty"`
 	SubtoolRequired bool          `json:"subtoolRequired,omitempty"`
 	Language        string        `json:"language,omitempty"`
 	License         string        `json:"license"`

gxutil/pm.go

@@ -23,6 +23,8 @@ const GxVersion = "0.12.1"
 
 const PkgFileName = "package.json"
 
+const DefaultTagCmd = "git tag -a \"v$VERSION\" -m \"gx release published as $HASH\""
+
 var installPathsCache map[string]string
 var binarySuffix string
 
@@ -208,6 +210,7 @@ func (pm *PM) InitPkg(dir, name, lang string, setup func(*Package)) error {
 			Version:    "0.0.0",
 			GxVersion:  GxVersion,
 			ReleaseCmd: "git commit -a -m \"gx publish $VERSION\"",
+			TagCmd:     DefaultTagCmd,
 		},
 	}
 

main.go

@@ -173,34 +173,41 @@ number. This is a soft requirement and can be skipped by specifying the
 			}
 		}
 
-		return doPublish(pkg)
+		if _, err := doPublish(pkg); err != nil {
+			return err
+		}
+
+		return nil
 	},
 }
 
-func doPublish(pkg *gx.Package) error {
+func doPublish(pkg *gx.Package) (string, error) {
 	if !pm.ShellOnline() {
-		return fmt.Errorf("ipfs daemon isn't running")
+		return "", fmt.Errorf("ipfs daemon isn't running")
 	}
 
 	err := gx.TryRunHook("pre-publish", pkg.Language, pkg.SubtoolRequired)
 	if err != nil {
-		return err
+		return "", err
 	}
 
 	hash, err := pm.PublishPackage(cwd, &pkg.PackageBase)
 	if err != nil {
-		return fmt.Errorf("publishing: %s", err)
+		return "", fmt.Errorf("publishing: %s", err)
 	}
 	log.Log("package %s published with hash: %s", pkg.Name, hash)
 
 	// write out version hash
 	err = writeLastPub(pkg.Version, hash)
 	if err != nil {
-		return err
+		return "", err
+	}
+
+	if err := gx.TryRunHook("post-publish", pkg.Language, pkg.SubtoolRequired, hash); err != nil {
+		return "", err
 	}
 
-	err = gx.TryRunHook("post-publish", pkg.Language, pkg.SubtoolRequired, hash)
-	return err
+	return hash, nil
 }
 
 func writeLastPub(vers string, hash string) error {
@@ -1235,12 +1242,12 @@ var ReleaseCommand = cli.Command{
 		}
 
 		fmt.Printf("publishing package...\r")
-		err = doPublish(pkg)
+		hash, err := doPublish(pkg)
 		if err != nil {
 			return err
 		}
 
-		return runRelease(pkg)
+		return runRelease(pkg, hash)
 	},
 }
 
@@ -1313,20 +1320,44 @@ func splitArgs(in string) []string {
 	return out
 }
 
-func escapeReleaseCmd(pkg *gx.Package, cmd string) string {
-	cmd = strings.Replace(cmd, "$VERSION", pkg.Version, -1)
+func escapeReleaseCmd(cmd, version, hash string) string {
+	cmd = strings.Replace(cmd, "$VERSION", version, -1)
+	cmd = strings.Replace(cmd, "$HASH", hash, -1)
 
 	return cmd
 }
 
-func runRelease(pkg *gx.Package) error {
+func runRelease(pkg *gx.Package, hash string) error {
 	if pkg.ReleaseCmd == "" {
+		fmt.Println("no release command defined, skipping")
 		return nil
 	}
 
-	replaced := escapeReleaseCmd(pkg, pkg.ReleaseCmd)
+	commitCmd := escapeReleaseCmd(pkg.ReleaseCmd, pkg.Version, hash)
+
+	if err := runCmd(commitCmd); err != nil {
+		return fmt.Errorf("failed to commit release: %s", err)
+	}
+
+	tagCmd := pkg.TagCmd
+	if tagCmd == "" {
+		// TODO: maybe don't do this? but otherwise we run into the issue that all existing
+		// gx configs don't have this defined, and would not start using tags :(
+		fmt.Println("no tag command defined, using default")
+		tagCmd = gx.DefaultTagCmd
+	}
+
+	tagCmd = escapeReleaseCmd(tagCmd, pkg.Version, hash)
+	if err := runCmd(tagCmd); err != nil {
+		return fmt.Errorf("failed to tag release: %s", err)
+	}
+
+	return nil
+}
+
+func runCmd(command string) error {
+	parts := splitArgs(command)
 
-	parts := splitArgs(replaced)
 	cmd := exec.Command(parts[0], parts[1:]...)
 	cmd.Stderr = os.Stderr
 	cmd.Stdout = os.Stdout