Add support for generic templates by using custom extra vars (#84)

* Fix DOCS.md example configuration with custom message from file

* Move .test.message to a better named file

* Add support for additional, custom extra vars to be used in the message template

* Add cmdline/envvars to support the extra vars

* Enhance DOCS.md with example configuration using generic template file with custom vars

* Add testcase for custom template vars

DOCS.md

@@ -152,6 +152,7 @@ Example configuration with a custom message template:
 Example configuration with a custom message template loaded from file:
 
 ```diff
+  - name: send telegram notification
     image: appleboy/drone-telegram
     settings:
       token: xxxxxxxxxx
@@ -159,6 +160,31 @@ Example configuration with a custom message template loaded from file:
 +     message_file: message_file.tpl
 ```
 
+Example configuration with a generic message template loaded from file, with additional extra vars:
+
+```diff
+  - name: send telegram notification
+    image: appleboy/drone-telegram
+    settings:
+      token: xxxxxxxxxx
+      to: telegram_user_id
++     message_file: message_file.tpl
++     template_vars:
++       env: testing
++       app: MyApp
+```
+
+Where `message_file.tpl` is:
+```
+Build finished for *{{tpl.app}}* - *{{tpl.env}}*
+
+{{#success build.status}}
+  build {{build.number}} succeeded. Good job.
+{{else}}
+  build {{build.number}} failed. Fix me please.
+{{/success}}
+```
+
 ## Parameter Reference
 
 token
@@ -173,6 +199,9 @@ message
 message_file
 : overwrite the default message template with the contents of the specified file
 
+template_vars
+: define additional template vars. Example: `var1: hello` can be used within the template as `tpl.var1`
+
 photo
 : local file path
 

main.go

@@ -41,6 +41,11 @@ func main() {
 			Usage:  "send telegram message from file",
 			EnvVar: "PLUGIN_MESSAGE_FILE,TELEGRAM_MESSAGE_FILE,INPUT_MESSAGE_FILE",
 		},
+		cli.StringFlag{
+			Name:   "template.vars",
+			Usage:  "additional template vars to be used in message, as JSON string",
+			EnvVar: "PLUGIN_TEMPLATE_VARS,TELEGRAM_TEMPLATE_VARS,INPUT_TEMPLATE_VARS",
+		},
 		cli.StringSliceFlag{
 			Name:   "photo",
 			Usage:  "send photo message",
@@ -294,6 +299,7 @@ func run(c *cli.Context) error {
 			To:           c.StringSlice("to"),
 			Message:      c.StringSlice("message"),
 			MessageFile:  c.String("message.file"),
+			TemplateVars: c.String("template.vars"),
 			Photo:        c.StringSlice("photo"),
 			Document:     c.StringSlice("document"),
 			Sticker:      c.StringSlice("sticker"),

plugin.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -66,6 +67,7 @@ type (
 		To           []string
 		Message      []string
 		MessageFile  string
+		TemplateVars string
 		Photo        []string
 		Document     []string
 		Sticker      []string
@@ -85,6 +87,7 @@ type (
 		Commit Commit
 		Build  Build
 		Config Config
+		Tpl    map[string]string
 	}
 
 	// Location format
@@ -258,9 +261,16 @@ func (p Plugin) Exec() (err error) {
 		message = p.Message()
 	}
 
+	if p.Config.TemplateVars != "" {
+		p.Tpl = make(map[string]string)
+		if err = json.Unmarshal([]byte(p.Config.TemplateVars), &p.Tpl); err != nil {
+			return fmt.Errorf("unable to unmarshall template vars from JSON string '%s': %v", p.Config.TemplateVars, err)
+		}
+	}
+
 	var bot *tgbotapi.BotAPI
 	if bot, err = tgbotapi.NewBotAPI(p.Config.Token); err != nil {
-		return err
+		return
 	}
 
 	bot.Debug = p.Config.Debug

plugin_test.go

@@ -347,7 +347,38 @@ func TestMessageFile(t *testing.T) {
 		Config: Config{
 			Token:       os.Getenv("TELEGRAM_TOKEN"),
 			To:          []string{os.Getenv("TELEGRAM_TO")},
-			MessageFile: "tests/.test.message",
+			MessageFile: "tests/message.txt",
+		},
+	}
+
+	err := plugin.Exec()
+	assert.Nil(t, err)
+}
+
+func TestTemplateVars(t *testing.T) {
+	plugin := Plugin{
+		Repo: Repo{
+			Name:      "go-hello",
+			Namespace: "appleboy",
+		},
+		Commit: Commit{
+			Sha:     "e7c4f0a63ceeb42a39ac7806f7b51f3f0d204fd2",
+			Author:  "Bo-Yi Wu",
+			Branch:  "master",
+			Message: "This is a test commit msg",
+		},
+		Build: Build{
+			Number: 101,
+			Status: "success",
+			Link:   "https://github.com/appleboy/go-hello",
+		},
+
+		Config: Config{
+			Token:        os.Getenv("TELEGRAM_TOKEN"),
+			To:           []string{os.Getenv("TELEGRAM_TO")},
+			Format:       "markdown",
+			MessageFile:  "tests/message_template.txt",
+			TemplateVars: `{"env":"testing","version":"1.2.0-SNAPSHOT"}`,
 		},
 	}
 

tests/message_template.txt

@@ -0,0 +1,7 @@
+Sample message template loaded from file.
+
+*Environ:* {{tpl.env}}
+*Version:* {{tpl.version}}
+
+Commit msg:  {{commit.message}}
+