Merge pull request #54 from Munsio/feature/gitlab-system-hooks

* Add gitlab system hook parsing

If you use gitlab system hooks you can now send push/tag_push/merge_request events

* Declare err and payload to avoid scope issues

* Refactor the whole event switch into own function

* Remove unnecessary comment

* Give the user the choice to parse SystemHooks

Author: Dean Karn

gitlab/gitlab.go

@@ -17,6 +17,7 @@ var (
 	ErrGitLabTokenVerificationFailed = errors.New("X-Gitlab-Token validation failed")
 	ErrEventNotFound                 = errors.New("event not defined to be parsed")
 	ErrParsingPayload                = errors.New("error parsing payload")
+	ErrParsingSystemPayload          = errors.New("error parsing system payload")
 	// ErrHMACVerificationFailed    = errors.New("HMAC verification failed")
 )
 
@@ -31,6 +32,11 @@ const (
 	WikiPageEvents           Event = "Wiki Page Hook"
 	PipelineEvents           Event = "Pipeline Hook"
 	BuildEvents              Event = "Build Hook"
+	SystemHookEvents         Event = "System Hook"
+
+	objectPush         string = "push"
+	objectTag          string = "tag_push"
+	objectMergeRequest string = "merge_request"
 )
 
 // Option is a configuration option for the webhook
@@ -55,7 +61,7 @@ type Webhook struct {
 	secret string
 }
 
-// Event defines a GitHub hook event type
+// Event defines a GitLab hook event type by the X-Gitlab-Event Header
 type Event string
 
 // New creates and returns a WebHook instance denoted by the Provider type
@@ -83,13 +89,31 @@ func (hook Webhook) Parse(r *http.Request, events ...Event) (interface{}, error)
 		return nil, ErrInvalidHTTPMethod
 	}
 
+	// If we have a Secret set, we should check the MAC
+	if len(hook.secret) > 0 {
+		signature := r.Header.Get("X-Gitlab-Token")
+		if signature != hook.secret {
+			return nil, ErrGitLabTokenVerificationFailed
+		}
+	}
+
 	event := r.Header.Get("X-Gitlab-Event")
 	if len(event) == 0 {
 		return nil, ErrMissingGitLabEventHeader
 	}
 
 	gitLabEvent := Event(event)
 
+	payload, err := ioutil.ReadAll(r.Body)
+	if err != nil || len(payload) == 0 {
+		return nil, ErrParsingPayload
+	}
+
+	return eventParsing(gitLabEvent, events, payload)
+}
+
+func eventParsing(gitLabEvent Event, events []Event, payload []byte) (interface{}, error) {
+
 	var found bool
 	for _, evt := range events {
 		if evt == gitLabEvent {
@@ -102,64 +126,68 @@ func (hook Webhook) Parse(r *http.Request, events ...Event) (interface{}, error)
 		return nil, ErrEventNotFound
 	}
 
-	payload, err := ioutil.ReadAll(r.Body)
-	if err != nil || len(payload) == 0 {
-		return nil, ErrParsingPayload
-	}
-
-	// If we have a Secret set, we should check the MAC
-	if len(hook.secret) > 0 {
-		signature := r.Header.Get("X-Gitlab-Token")
-		if signature != hook.secret {
-			return nil, ErrGitLabTokenVerificationFailed
-		}
-	}
-
 	switch gitLabEvent {
 	case PushEvents:
 		var pl PushEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case TagEvents:
 		var pl TagEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case ConfidentialIssuesEvents:
 		var pl ConfidentialIssueEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case IssuesEvents:
 		var pl IssueEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case CommentEvents:
 		var pl CommentEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case MergeRequestEvents:
 		var pl MergeRequestEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case WikiPageEvents:
 		var pl WikiPageEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case PipelineEvents:
 		var pl PipelineEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
 
 	case BuildEvents:
 		var pl BuildEventPayload
-		err = json.Unmarshal([]byte(payload), &pl)
+		err := json.Unmarshal([]byte(payload), &pl)
 		return pl, err
+
+	case SystemHookEvents:
+		var pl SystemHookPayload
+		err := json.Unmarshal([]byte(payload), &pl)
+		if err != nil {
+			return nil, err
+		}
+		switch pl.ObjectKind {
+		case objectPush:
+			return eventParsing(PushEvents, events, payload)
+		case objectTag:
+			return eventParsing(TagEvents, events, payload)
+		case objectMergeRequest:
+			return eventParsing(MergeRequestEvents, events, payload)
+		default:
+			return nil, fmt.Errorf("unknown system hook event %s", gitLabEvent)
+		}
 	default:
 		return nil, fmt.Errorf("unknown event %s", gitLabEvent)
 	}

gitlab/gitlab_test.go

@@ -2,15 +2,13 @@ package gitlab
 
 import (
 	"bytes"
+	"io"
 	"log"
 	"net/http"
 	"net/http/httptest"
 	"os"
-	"testing"
-
-	"io"
-
 	"reflect"
+	"testing"
 
 	"github.com/stretchr/testify/require"
 )
@@ -266,3 +264,62 @@ func TestWebhooks(t *testing.T) {
 		})
 	}
 }
+
+func TestSystemHooks(t *testing.T) {
+	assert := require.New(t)
+	tests := []struct {
+		name     string
+		event    Event
+		typ      interface{}
+		filename string
+	}{
+		{
+			name:     "PushEvent",
+			event:    PushEvents,
+			typ:      PushEventPayload{},
+			filename: "../testdata/gitlab/push-event.json",
+		},
+		{
+			name:     "TagEvent",
+			event:    TagEvents,
+			typ:      TagEventPayload{},
+			filename: "../testdata/gitlab/tag-event.json",
+		},
+		{
+			name:     "MergeRequestEvent",
+			event:    MergeRequestEvents,
+			typ:      MergeRequestEventPayload{},
+			filename: "../testdata/gitlab/merge-request-event.json",
+		},
+	}
+	for _, tt := range tests {
+		tc := tt
+		client := &http.Client{}
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			payload, err := os.Open(tc.filename)
+			assert.NoError(err)
+			defer func() {
+				_ = payload.Close()
+			}()
+
+			var parseError error
+			var results interface{}
+			server := newServer(func(w http.ResponseWriter, r *http.Request) {
+				results, parseError = hook.Parse(r, SystemHookEvents, tc.event)
+			})
+			defer server.Close()
+			req, err := http.NewRequest(http.MethodPost, server.URL+path, payload)
+			assert.NoError(err)
+			req.Header.Set("Content-Type", "application/json")
+			req.Header.Set("X-Gitlab-Token", "sampleToken!")
+			req.Header.Set("X-Gitlab-Event", "System Hook")
+
+			resp, err := client.Do(req)
+			assert.NoError(err)
+			assert.Equal(http.StatusOK, resp.StatusCode)
+			assert.NoError(parseError)
+			assert.Equal(reflect.TypeOf(tc.typ), reflect.TypeOf(results))
+		})
+	}
+}

gitlab/payload.go

@@ -148,6 +148,11 @@ type BuildEventPayload struct {
 	Repository        Repository  `json:"repository"`
 }
 
+// SystemHookPayload contains the ObjectKind to match with real hook events
+type SystemHookPayload struct {
+	ObjectKind string `json:"object_kind"`
+}
+
 // Issue contains all of the GitLab issue information
 type Issue struct {
 	ID          int64      `json:"id"`