Merge pull request #161 from moorereason/templates

Allow hooks file to be parsed as a template

hook/hook.go

@@ -1,6 +1,7 @@
 package hook
 
 import (
+	"bytes"
 	"crypto/hmac"
 	"crypto/sha1"
 	"crypto/sha256"
@@ -18,6 +19,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"text/template"
 
 	"github.com/ghodss/yaml"
 )
@@ -544,8 +546,10 @@ func (h *Hook) ExtractCommandArgumentsForFile(headers, query, payload *map[strin
 // Hooks is an array of Hook objects
 type Hooks []Hook
 
-// LoadFromFile attempts to load hooks from specified JSON file
-func (h *Hooks) LoadFromFile(path string) error {
+// LoadFromFile attempts to load hooks from the specified file, which
+// can be either JSON or YAML.  The asTemplate parameter causes the file
+// contents to be parsed as a Go text/template prior to unmarshalling.
+func (h *Hooks) LoadFromFile(path string, asTemplate bool) error {
 	if path == "" {
 		return nil
 	}
@@ -557,6 +561,24 @@ func (h *Hooks) LoadFromFile(path string) error {
 		return e
 	}
 
+	if asTemplate {
+		funcMap := template.FuncMap{"getenv": getenv}
+
+		tmpl, err := template.New("hooks").Funcs(funcMap).Parse(string(file))
+		if err != nil {
+			return err
+		}
+
+		var buf bytes.Buffer
+
+		err = tmpl.Execute(&buf, nil)
+		if err != nil {
+			return err
+		}
+
+		file = buf.Bytes()
+	}
+
 	e = yaml.Unmarshal(file, h)
 	return e
 }
@@ -705,3 +727,8 @@ func (r MatchRule) Evaluate(headers, query, payload *map[string]interface{}, bod
 	}
 	return false, nil
 }
+
+// getenv provides a template function to retrieve OS environment variables.
+func getenv(s string) string {
+	return os.Getenv(s)
+}

hook/hook_test.go

@@ -1,6 +1,7 @@
 package hook
 
 import (
+	"os"
 	"reflect"
 	"strings"
 	"testing"
@@ -229,26 +230,55 @@ func TestHookExtractCommandArgumentsForEnv(t *testing.T) {
 }
 
 var hooksLoadFromFileTests = []struct {
-	path string
-	ok   bool
+	path       string
+	asTemplate bool
+	ok         bool
 }{
-	{"../hooks.json.example", true},
-	{"../hooks.yaml.example", true},
-	{"", true},
+	{"../hooks.json.example", false, true},
+	{"../hooks.yaml.example", false, true},
+	{"../hooks.json.tmpl.example", true, true},
+	{"../hooks.yaml.tmpl.example", true, true},
+	{"", false, true},
 	// failures
-	{"missing.json", false},
+	{"missing.json", false, false},
 }
 
 func TestHooksLoadFromFile(t *testing.T) {
+	secret := `foo"123`
+	os.Setenv("XXXTEST_SECRET", secret)
+
 	for _, tt := range hooksLoadFromFileTests {
 		h := &Hooks{}
-		err := h.LoadFromFile(tt.path)
+		err := h.LoadFromFile(tt.path, tt.asTemplate)
 		if (err == nil) != tt.ok {
 			t.Errorf(err.Error())
 		}
 	}
 }
 
+func TestHooksTemplateLoadFromFile(t *testing.T) {
+	secret := `foo"123`
+	os.Setenv("XXXTEST_SECRET", secret)
+
+	for _, tt := range hooksLoadFromFileTests {
+		if !tt.asTemplate {
+			continue
+		}
+
+		h := &Hooks{}
+		err := h.LoadFromFile(tt.path, tt.asTemplate)
+		if (err == nil) != tt.ok {
+			t.Errorf(err.Error())
+			continue
+		}
+
+		s := (*h.Match("webhook").TriggerRule.And)[0].Match.Secret
+		if s != secret {
+			t.Errorf("Expected secret of %q, got %q", secret, s)
+		}
+	}
+}
+
 var hooksMatchTests = []struct {
 	id    string
 	hooks Hooks

hooks.json.tmpl.example

@@ -0,0 +1,60 @@
+[
+  {
+    "id": "webhook",
+    "execute-command": "/home/adnan/redeploy-go-webhook.sh",
+    "command-working-directory": "/home/adnan/go",
+    "response-message": "I got the payload!",
+    "response-headers":
+    [
+      {
+        "name": "Access-Control-Allow-Origin",
+        "value": "*"
+      }
+    ],
+    "pass-arguments-to-command":
+    [
+      {
+        "source": "payload",
+        "name": "head_commit.id"
+      },
+      {
+        "source": "payload",
+        "name": "pusher.name"
+      },
+      {
+        "source": "payload",
+        "name": "pusher.email"
+      }
+    ],
+    "trigger-rule":
+    {
+      "and":
+      [
+        {
+          "match":
+          {
+            "type": "payload-hash-sha1",
+            "secret": "{{ getenv "XXXTEST_SECRET" | js }}",
+            "parameter":
+            {
+              "source": "header",
+              "name": "X-Hub-Signature"
+            }
+          }
+        },
+        {
+          "match":
+          {
+            "type": "value",
+            "value": "refs/heads/master",
+            "parameter":
+            {
+              "source": "payload",
+              "name": "ref"
+            }
+          }
+        }
+      ]
+    }
+  }
+]

hooks.yaml.tmpl.example

@@ -0,0 +1,28 @@
+- id: webhook
+  execute-command: /home/adnan/redeploy-go-webhook.sh
+  command-working-directory: /home/adnan/go
+  response-message: I got the payload!
+  response-headers:
+  - name: Access-Control-Allow-Origin
+    value: '*'
+  pass-arguments-to-command:
+  - source: payload
+    name: head_commit.id
+  - source: payload
+    name: pusher.name
+  - source: payload
+    name: pusher.email
+  trigger-rule:
+    and:
+    - match:
+        type: payload-hash-sha1
+        secret: "{{ getenv "XXXTEST_SECRET" | js }}"
+        parameter:
+          source: header
+          name: X-Hub-Signature
+    - match:
+        type: value
+        value: refs/heads/master
+        parameter:
+          source: payload
+          name: ref

webhook.go

@@ -34,6 +34,7 @@ var (
 	hotReload          = flag.Bool("hotreload", false, "watch hooks file for changes and reload them automatically")
 	hooksURLPrefix     = flag.String("urlprefix", "hooks", "url prefix to use for served hooks (protocol://yourserver:port/PREFIX/:hook-id)")
 	secure             = flag.Bool("secure", false, "use HTTPS instead of HTTP")
+	asTemplate         = flag.Bool("template", false, "parse hooks file as a Go template")
 	cert               = flag.String("cert", "cert.pem", "path to the HTTPS certificate pem file")
 	key                = flag.String("key", "key.pem", "path to the HTTPS certificate private key pem file")
 	justDisplayVersion = flag.Bool("version", false, "display webhook version and quit")
@@ -99,7 +100,7 @@ func main() {
 
 		newHooks := hook.Hooks{}
 
-		err := newHooks.LoadFromFile(hooksFilePath)
+		err := newHooks.LoadFromFile(hooksFilePath, *asTemplate)
 
 		if err != nil {
 			log.Printf("couldn't load hooks from file! %+v\n", err)
@@ -407,7 +408,7 @@ func reloadHooks(hooksFilePath string) {
 	// parse and swap
 	log.Printf("attempting to reload hooks from %s\n", hooksFilePath)
 
-	err := hooksInFile.LoadFromFile(hooksFilePath)
+	err := hooksInFile.LoadFromFile(hooksFilePath, *asTemplate)
 
 	if err != nil {
 		log.Printf("couldn't load hooks from file! %+v\n", err)