Add GitInfo

This commit adds a `GitInfo` object to `Page` if `EnableGitInfo` is set.

It then also sets `Lastmod` for the given `Page` to the author date provided by Git.

The Git integrations should be fairly performant, but it adds "some time" to the build, somewhat depending on the Git history size.

If you want, you can run without during development and turn it on when deploying to the live server: `hugo --enableGitInfo`.

Fixes #2102

commands/hugo.go

@@ -133,6 +133,7 @@ var (
 	canonifyURLs          bool
 	cleanDestination      bool
 	enableRobotsTXT       bool
+	enableGitInfo         bool
 	disable404            bool
 	disableRSS            bool
 	disableSitemap        bool
@@ -237,6 +238,7 @@ func initHugoBuildCommonFlags(cmd *cobra.Command) {
 	cmd.Flags().BoolVar(&uglyURLs, "uglyURLs", false, "if true, use /filename.html instead of /filename/")
 	cmd.Flags().BoolVar(&canonifyURLs, "canonifyURLs", false, "if true, all relative URLs will be canonicalized using baseURL")
 	cmd.Flags().StringVarP(&baseURL, "baseURL", "b", "", "hostname (and path) to the root, e.g. http://spf13.com/")
+	cmd.Flags().BoolVar(&enableGitInfo, "enableGitInfo", false, "Add Git revision, date and author info to the pages")
 
 	cmd.Flags().BoolVar(&nitro.AnalysisOn, "stepAnalysis", false, "display memory and timing of different steps of the program")
 	cmd.Flags().BoolVar(&pluralizeListTitles, "pluralizeListTitles", true, "Pluralize titles in lists using inflect")
@@ -319,6 +321,9 @@ func InitializeConfig(subCmdVs ...*cobra.Command) error {
 		if flagChanged(cmdV.Flags(), "enableRobotsTXT") {
 			viper.Set("enableRobotsTXT", enableRobotsTXT)
 		}
+		if flagChanged(cmdV.Flags(), "enableGitInfo") {
+			viper.Set("enableGitInfo", enableGitInfo)
+		}
 		if flagChanged(cmdV.Flags(), "pluralizeListTitles") {
 			viper.Set("pluralizeListTitles", pluralizeListTitles)
 		}

docs/config.toml

@@ -2,6 +2,7 @@ title = "Hugo: A Fast and Flexible Website Generator"
 baseurl = "http://gohugo.io/"
 MetaDataFormat = "yaml"
 pluralizeListTitles = false
+enableGitInfo = true
 
 [blackfriday]
   plainIDAnchors = true

docs/layouts/partials/footer.html

@@ -1,6 +1,6 @@
                     <div class="row">
                         <div class="footer-panel">
-                        <p>Last revision: {{ .Lastmod.Format "January 2, 2006" }}
+                        <p>Last revision: {{ .Lastmod.Format "January 2, 2006" }}{{ if .IsPage }}<em>{{ with .GitInfo }}| {{ .Subject }} | {{ .AbbreviatedHash }}{{end }}</em>{{ end }}
                           <span style="float: right;">Hugo v{{ .Hugo.Version }} documentation</span>
                         </p>
                         </div>

hugolib/config.go

@@ -106,4 +106,5 @@ func loadDefaultSettings() {
 	viper.SetDefault("defaultContentLanguage", "en")
 	viper.SetDefault("defaultContentLanguageInSubdir", false)
 	viper.SetDefault("enableMissingTranslationPlaceholders", false)
+	viper.SetDefault("enableGitInfo", false)
 }

hugolib/gitinfo.go

@@ -0,0 +1,67 @@
+// Copyright 2016-present The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugolib
+
+import (
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/bep/gitmap"
+	"github.com/spf13/hugo/helpers"
+	jww "github.com/spf13/jwalterweatherman"
+	"github.com/spf13/viper"
+)
+
+func (h *HugoSites) assembleGitInfo() {
+	if !viper.GetBool("enableGitInfo") {
+		return
+	}
+
+	var (
+		workingDir = viper.GetString("workingDir")
+		contentDir = viper.GetString("contentDir")
+	)
+
+	gitRepo, err := gitmap.Map(workingDir, "")
+	if err != nil {
+		jww.ERROR.Printf("Got error reading Git log: %s", err)
+		return
+	}
+
+	gitMap := gitRepo.Files
+	repoPath := filepath.FromSlash(gitRepo.TopLevelAbsPath)
+
+	// The Hugo site may be placed in a sub folder in the Git repo,
+	// one example being the Hugo docs.
+	// We have to find the root folder to the Hugo site below the Git root.
+	contentRoot := strings.TrimPrefix(workingDir, repoPath)
+	contentRoot = strings.TrimPrefix(contentRoot, helpers.FilePathSeparator)
+
+	s := h.Sites[0]
+
+	for _, p := range s.AllPages {
+		// Git normalizes file paths on this form:
+		filename := path.Join(contentRoot, contentDir, filepath.ToSlash(p.Path()))
+		g, ok := gitMap[filename]
+		if !ok {
+			jww.ERROR.Printf("Failed to find GitInfo for %q", filename)
+			return
+		}
+
+		p.GitInfo = g
+		p.Lastmod = p.GitInfo.AuthorDate
+	}
+
+}

hugolib/hugo_sites.go

@@ -216,6 +216,9 @@ func (h *HugoSites) Build(config BuildCfg) error {
 		}
 	}
 
+	// TODO(bep) make a more logical grouping of these.
+	h.assembleGitInfo()
+
 	for _, s := range h.Sites {
 		if err := s.postProcess(); err != nil {
 			return err
@@ -288,6 +291,7 @@ func (h *HugoSites) Rebuild(config BuildCfg, events ...fsnotify.Event) error {
 	h.setupTranslations(firstSite)
 
 	if changed.source {
+		h.assembleGitInfo()
 		for _, s := range h.Sites {
 			if err := s.postProcess(); err != nil {
 				return err

hugolib/page.go

@@ -19,6 +19,8 @@ import (
 	"fmt"
 	"reflect"
 
+	"github.com/bep/gitmap"
+
 	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/hugo/helpers"
 	"github.com/spf13/hugo/parser"
@@ -94,6 +96,8 @@ type Page struct {
 	Source
 	Position `json:"-"`
 	Node
+
+	GitInfo *gitmap.GitInfo
 }
 
 type Source struct {

vendor/vendor.json

@@ -20,6 +20,12 @@
 			"revision": "5bd2802263f21d8788851d5305584c82a5c75d7e",
 			"revisionTime": "2016-07-26T15:08:25Z"
 		},
+		{
+			"checksumSHA1": "dIidE/pUkqulIvTkuMBTpH3/lnU=",
+			"path": "github.com/bep/gitmap",
+			"revision": "a1a71abe12823e27ae7507189fe2e914ba9626ac",
+			"revisionTime": "2016-10-29T14:53:16Z"
+		},
 		{
 			"checksumSHA1": "K8wTIgrK5sl+LmQs8CD/orvKsAM=",
 			"path": "github.com/bep/inflect",