Generate footer from template

Signed-off-by: David Pordomingo <David.Pordomingo.F@gmail.com>

Author: dpordomingo

.helm-staging.yml

@@ -27,7 +27,7 @@ providers:
     app_id: 17877
     private_key: /local/lookout/private-key.pem
     secretName: lookout-staging-github-key
-    comment_footer: '_If you have feedback about this comment, please, [tell us](%s)._'
+    comment_footer: "_{{if .Feedback}}If you have feedback about this comment made by the analyzer {{.Name}}, please, [tell us]({{.Feedback}}){{else}}Comment made by the analyzer {{.Name}}{{end}}._"
     installation_sync_interval: 5m
 
 analyzers:

cmd/lookoutd/common.go

@@ -324,7 +324,7 @@ func (c *queueConsumerCommand) initPoster(conf Config) (lookout.Poster, error) {
 
 	switch c.Provider {
 	case github.Provider:
-		return github.NewPoster(c.pool, conf.Providers.Github), nil
+		return github.NewPoster(c.pool, conf.Providers.Github)
 	case json.Provider:
 		return json.NewPoster(os.Stdout), nil
 	default:

config.yml.tpl

@@ -8,7 +8,7 @@ analyzers:
 
 providers:
   github:
-    comment_footer: '_If you have feedback about this comment, please, [tell us](%s)._'
+    comment_footer: "_{{if .Feedback}}If you have feedback about this comment made by the analyzer {{.Name}}, please, [tell us]({{.Feedback}}){{else}}Comment made by the analyzer {{.Name}}{{end}}._"
     # The minimum watch interval to discover new pull requests and push events
     watch_min_interval: 2s
     # Authorization with GitHub App

docs/configuration.md

@@ -39,14 +39,14 @@ The `providers.github` key configures how **source{d} Lookout** will connect wit
 ```yaml
 providers:
   github:
-    comment_footer: "_If you have feedback about this comment, please, [tell us](%s)._"
+    comment_footer: "_Comment made by '{{.Name}}'{{with .Feedback}}, [tell us]({{.}}){{end}}._"
     # app_id: 1234
     # private_key: ./key.pem
     # installation_sync_interval: 1h
     # watch_min_interval: 2s
 ```
 
-`comment_footer` key defines a format-string that will be used for custom messages for every message posted on GitHub; see how to [add a custom message to the posted comments](#add-a-custom-message-to-the-posted-comments)
+`comment_footer` key defines the [go template](https://golang.org/pkg/text/template) that will be used for custom messages for every message posted on GitHub; see how to [add a custom message to the posted comments](#add-a-custom-message-to-the-posted-comments)
 
 ### Authentication with GitHub
 
@@ -141,17 +141,31 @@ analyzers:
 
 ### Add a Custom Message to the Posted Comments
 
-You can configure **source{d} Lookout** to add a custom message to every comment that each analyzer returns. This custom message will be created following the rule:
-```
-sprintf(providers.github.comment_footer, feedback)
-```
-If any of those two keys are not defined, the custom message won't be added.
+You can configure **source{d} Lookout** to add a custom message to every comment that each analyzer returns. This custom message will be created from the template defined by `providers.github.comment_footer`, using the configuration set for each analyzer.
 
-Example:
-```text
-"_If you have feedback about this comment, please, [tell us](%s)._"
+If the template (`providers.github.comment_footer`) is empty, or the analyzer configuration does not define any of the values that the template requires, the custom message won't be added.
+
+For example, for this configuration, each analyzer needs to define `name` and `settings.email`:
+
+```yaml
+providers:
+  github:
+    comment_footer: "Comment made by analyzer {{.Name}}, [email me]({{.Settings.email}})."
+
+analyzers:
+  - name: Fancy Analyzer
+    addr: ipv4://localhost:9930
+    settings:
+      email: admin@example.org
+  - name: Awesome Analyzer
+    addr: ipv4://localhost:9931
 ```
 
+Comments from `Fancy Analyzer` will have this footer appended:
+>_Comment made by analyzer Fancy Analyzer, [email me](admin@example.org)._
+
+but comments from `Awesome Analyzer` wont have a footer message because in its configuration it's missing the `settings.email` value.
+
 
 ## Timeouts
 

provider/github/poster.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
+	"text/template"
 
 	"github.com/src-d/lookout"
 	"github.com/src-d/lookout/util/ctxlog"
@@ -32,18 +33,27 @@ const (
 
 // Poster posts comments as Pull Request Reviews.
 type Poster struct {
-	pool *ClientPool
-	conf ProviderConfig
+	pool           *ClientPool
+	conf           ProviderConfig
+	footerTemplate *template.Template
 }
 
 var _ lookout.Poster = &Poster{}
 
 // NewPoster creates a new poster for the GitHub API.
-func NewPoster(pool *ClientPool, conf ProviderConfig) *Poster {
-	return &Poster{
-		pool: pool,
-		conf: conf,
+func NewPoster(pool *ClientPool, conf ProviderConfig) (*Poster, error) {
+	tpl, err := newFooterTemplate(conf.CommentFooter)
+	if ErrEmptyTemplate.Is(err) {
+		log.DefaultLogger.Warningf("no footer template being used: %s", err)
+	} else if err != nil {
+		return nil, err
 	}
+
+	return &Poster{
+		pool:           pool,
+		conf:           conf,
+		footerTemplate: tpl,
+	}, nil
 }
 
 // Post posts comments as a Pull Request Review.
@@ -157,15 +167,11 @@ func (p *Poster) createReviewRequest(
 	}
 
 	var bodyComments []string
-	tmpl := p.conf.CommentFooter
-
 	for _, aComments := range aCommentsList {
 		ctx, _ := ctxlog.WithLogFields(ctx, log.Fields{
 			"analyzer": aComments.Config.Name,
 		})
 
-		url := aComments.Config.Feedback
-
 		forBody, ghComments := convertComments(ctx, aComments.Comments, dl)
 
 		if len(postedComments) > 0 {
@@ -175,13 +181,13 @@ func (p *Poster) createReviewRequest(
 		ghComments = mergeComments(ghComments)
 
 		for i, c := range ghComments {
-			body := addFootnote(c.GetBody(), tmpl, url)
+			body := addFootnote(ctx, c.GetBody(), p.footerTemplate, &aComments.Config)
 			ghComments[i].Body = &body
 		}
 
 		bodyComments = append(
 			bodyComments,
-			addFootnote(strings.Join(forBody, "\n\n"), tmpl, url),
+			addFootnote(ctx, strings.Join(forBody, "\n\n"), p.footerTemplate, &aComments.Config),
 		)
 		req.Comments = append(req.Comments, ghComments...)
 	}

provider/github/poster_test.go

@@ -205,11 +205,10 @@ func (s *PosterTestSuite) TestPostFooter() {
 	aComments := mockAnalyzerComments
 	aComments[0].Config.Feedback = "https://foo.bar/feedback"
 
+	footerTpl, _ := newFooterTemplate("To post feedback go to {{.Feedback}}")
 	p := &Poster{
-		pool: s.pool,
-		conf: ProviderConfig{
-			CommentFooter: "To post feedback go to %s",
-		},
+		pool:           s.pool,
+		footerTemplate: footerTpl,
 	}
 	err := p.Post(context.Background(), mockEvent, aComments, false)
 	s.NoError(err)
@@ -526,3 +525,22 @@ func intptr(v int) *int {
 func int64ptr(v int64) *int64 {
 	return &v
 }
+
+func (s *PosterTestSuite) TestCouldNotParseFooterTemplate() {
+	emptyTemplateRaw := ""
+	posterWithEmptyTemplate, err := NewPoster(nil, ProviderConfig{CommentFooter: emptyTemplateRaw})
+	s.Nil(err, "NewPoster must return no error when parsing an empty template")
+	emptyTemplate := posterWithEmptyTemplate.footerTemplate
+	commentsEmptyTemplate := addFootnote(context.TODO(), "comments", emptyTemplate, nil)
+	s.Equal("comments", commentsEmptyTemplate)
+
+	oldTemplateRaw := "Old template %s"
+	posterWithOldTemplate, err := NewPoster(nil, ProviderConfig{CommentFooter: oldTemplateRaw})
+	s.Nil(posterWithOldTemplate, "NewPoster must fail when parsing an old template config")
+	s.True(ErrOldTemplate.Is(err), "Error should be 'ErrOldTemplate'")
+
+	wrongTemplateeRaw := "Old template {{{parseerror"
+	posterWithWrongTemplate, err := NewPoster(nil, ProviderConfig{CommentFooter: wrongTemplateeRaw})
+	s.Nil(posterWithWrongTemplate, "NewPoster must fail when parsing a wrong template config")
+	s.True(ErrParseTemplate.Is(err), "Error should be 'ErrParseTemplate'")
+}

provider/github/review.go

@@ -2,14 +2,15 @@ package github
 
 import (
 	"context"
-	"fmt"
 	"sort"
 	"strings"
+	"text/template"
 	"time"
 
 	"github.com/google/go-github/github"
 	"github.com/src-d/lookout"
 	"github.com/src-d/lookout/util/ctxlog"
+	errors "gopkg.in/src-d/go-errors.v1"
 	log "gopkg.in/src-d/go-log.v1"
 )
 
@@ -29,6 +30,13 @@ const commentsSeparator = "\n<!-- lookout comment separator -->\n---\n"
 // comment can contain footer with link to the analyzer
 const footnoteSeparator = "\n<!-- lookout footnote separator -->\n"
 
+var (
+	ErrEmptyTemplate = errors.NewKind("empty footer template")
+	ErrOldTemplate   = errors.NewKind("old footer template: '%%s' placeholder is no longer supported: '%s'")
+	ErrParseTemplate = errors.NewKind("error parsing footer template: %s")
+	ErrTemplateError = errors.NewKind("error generating the footer: %s")
+)
+
 // createReview creates pull request review on github using multiple http calls
 // in case of too many comments
 func createReview(
@@ -207,13 +215,53 @@ func splitReviewRequest(review *github.PullRequestReviewRequest, n int) []*githu
 	return result
 }
 
+func newFooterTemplate(tpl string) (*template.Template, error) {
+	if tpl == "" {
+		return nil, ErrEmptyTemplate.New()
+	}
+
+	if strings.Index(tpl, "%s") >= 0 {
+		return nil, ErrOldTemplate.New(tpl)
+	}
+
+	template, err := template.New("footer").Parse(tpl)
+	if err != nil {
+		return nil, ErrParseTemplate.New(err)
+	}
+
+	return template.Option("missingkey=error"), nil
+}
+
 // addFootnote adds footnote link to text of a comment
-func addFootnote(text, tmpl, url string) string {
-	if text == "" || tmpl == "" || url == "" {
-		return text
+func addFootnote(
+	ctx context.Context,
+	comment string, tmpl *template.Template, analyzerConf *lookout.AnalyzerConfig,
+) string {
+	if comment == "" || tmpl == nil {
+		return comment
+	}
+
+	footer, err := getFootnote(tmpl, analyzerConf)
+	if err != nil {
+		ctxlog.Get(ctx).Warningf("footer could not be generated: %s", err)
+		return comment
+	}
+
+	return comment + footer
+}
+
+func getFootnote(tmpl *template.Template, analyzerConf *lookout.AnalyzerConfig) (string, error) {
+	var footer strings.Builder
+	if err := tmpl.Execute(&footer, analyzerConf); err != nil {
+		return "", ErrTemplateError.New(err)
+	}
+
+	footerTxt := footer.String()
+	if footerTxt == "" {
+		return "", nil
 	}
 
-	return text + footnoteSeparator + fmt.Sprintf(tmpl, url)
+	return footnoteSeparator + footer.String(), nil
 }
 
 // removeFootnote removes footnote and returns only text of a comment

provider/github/review_test.go

@@ -225,3 +225,12 @@ func TestConvertCommentsWrongFile(t *testing.T) {
 		Body:     strptr("Line comment"),
 	}}, ghComments)
 }
+
+func TestCouldNotExecuteFooterTemplate(t *testing.T) {
+	require := require.New(t)
+
+	unkonwnDataTemplate, err := newFooterTemplate("Old template {{.UnknownData}}")
+	require.Nil(err)
+	commentsWrongTemplate := addFootnote(context.TODO(), "comments", unkonwnDataTemplate, nil)
+	require.Equal("comments", commentsWrongTemplate)
+}