Enable logging and debug of nodemailer (#190)

This should help A LOT to let people understand
why things go wrong in this action when talking to the mailhost

.github/workflows/test.yml

@@ -42,7 +42,7 @@ jobs:
             html_body: file://README.md
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Send mail
         uses: ./
         with:
@@ -63,7 +63,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Send mail
         uses: ./
         with:

README.md

@@ -60,6 +60,10 @@ Some features:
     attachments: attachments.zip,git.diff,./dist/static/*.js
     # Optional priority: 'high', 'normal' (default) or 'low'
     priority: low
+    # Optional nodemailerlog: true/false
+    nodemailerlog: false
+    # Optional nodemailerdebug: true/false if true lognodem will also be set true
+    nodemailerdebug: false
 ```
 
 ## Troubleshooting

action.yml

@@ -23,7 +23,7 @@ inputs:
     required: true
   to:
     description: Recipients mail addresses (separated with comma)
-    required: true
+    required: false
   from:
     description: Full name of mail sender (might be with an email address specified in <>)
     required: true
@@ -57,6 +57,12 @@ inputs:
   priority:
     description: Set Priority level for the mail message to 'high', 'normal' (default) or 'low'
     required: false
+  nodemailerlog:
+    description: Log option for nodemailer
+    required: false
+  nodemailerdebug:
+    description: Debug option for nodemailer
+    required: false
 runs:
   using: node16
   main: main.js

main.js

@@ -80,7 +80,7 @@ async function main() {
 
         const subject = core.getInput("subject", { required: true })
         const from = core.getInput("from", { required: true })
-        const to = core.getInput("to", { required: true })
+        const to = core.getInput("to", { required: false })
         const body = core.getInput("body", { required: false })
         const htmlBody = core.getInput("html_body", { required: false })
         const cc = core.getInput("cc", { required: false })
@@ -91,15 +91,18 @@ async function main() {
         const convertMarkdown = core.getInput("convert_markdown", { required: false })
         const ignoreCert = core.getInput("ignore_cert", { required: false })
         const priority = core.getInput("priority", { required: false })
+        const nodemailerlog = core.getInput("nodemailerlog", { required: false })
+        const nodemailerdebug = core.getInput("nodemailerdebug", { required: false })
+
+        // if neither to, cc or bcc is provided, throw error
+        if (!to && !cc && !bcc) {
+            throw new Error("At least one of 'to', 'cc' or 'bcc' must be specified")
+        }
         
         if (!serverAddress) {
             throw new Error("Server address must be specified")
         }
 
-        if (!username || !password) {
-            core.warning("Username and password not specified. You should only do this if you are using a self-hosted runner to access an on-premise mail server.")
-        }
-
         const transport = nodemailer.createTransport({
             host: serverAddress,
             auth: username && password ? {
@@ -111,6 +114,8 @@ async function main() {
             tls: ignoreCert == "true" ? {
                 rejectUnauthorized: false
             } : undefined,
+            logger: nodemailerdebug == "true" ? true : nodemailerlog,
+            debug: nodemailerdebug,
         })
 
         const info = await transport.sendMail({