finished healthcheck improvements and added troubleshooting info for …

…kubernetes

Dockerfile

@@ -3,11 +3,13 @@ FROM node:15-alpine
 ENV NODE_ENV=production
 
 ENV CORS=""
+ENV PORT=80
 
 ENV MJML_KEEP_COMMENTS=false
 ENV MJML_VALIDATION_LEVEL=soft
 ENV MJML_MINIFY=true
 ENV MJML_MINIFY=false
+ENV HEALTHCHECK=true
 
 COPY package* ./
 
@@ -20,9 +22,8 @@ COPY index.js ./index.js
 
 COPY healthcheck.sh /healthcheck.sh
 
-HEALTHCHECK --timeout=30s \
-  CMD /healthcheck.sh || exit 1
+HEALTHCHECK --start-period=10s --retries=1 CMD /healthcheck.sh || exit 1
 
 EXPOSE 80
 
-ENTRYPOINT [ "node", "index.js"]
+ENTRYPOINT [ "node", "index.js" ]

README.md

@@ -14,6 +14,7 @@ Due to various challenges this image sports the following features:
   - [Defaults](#defaults)
   - [Development](#development)
   - [Troubleshooting](#troubleshooting)
+    - [Kubernetes](#kubernetes)
 
 ## Overview
 
@@ -36,7 +37,7 @@ services:
   mjml:
     image: adrianrudnik/mjml-server
     ports:
-      - 8889:80
+      - 8080:80
     # environment:
     # to change the port:
     #   - PORT=8080
@@ -58,6 +59,7 @@ MJML_KEEP_COMMENTS "false"
 MJML_VALIDATION_LEVEL "soft"
 MJML_MINIFY "true"
 MJML_BEAUTIFY "false"
+HEALTHCHECK "true"
 ```
 
 ## Development
@@ -70,6 +72,7 @@ MJML_KEEP_COMMENTS "true"
 MJML_VALIDATION_LEVEL "strict"
 MJML_MINIFY "false"
 MJML_BEAUTIFY "true"
+HEALTHCHECK "false"
 ```
 
 This will escalate any issues you have with invalid mjml code to the docker log (`stdout` or `docker-compose logs`).
@@ -79,3 +82,26 @@ This will escalate any issues you have with invalid mjml code to the docker log
 Make sure you pass along a plain Content-Type header and pass the mjml as raw body.
 
 Catch errors by looking at the HTTP response code.
+
+### Kubernetes
+
+As the default Dockerfile specific `HEALTHCHECK` directive is not supported by kubernetes, you might need to specify your own probes:
+
+```
+spec:
+  containers:
+  - name: ...
+    livenessProbe:
+      exec:
+        command:
+        - curl - -X POST - 'http://localhost:80/'
+      initialDelaySeconds: 30
+      periodSeconds: 30
+    readinessProbe:
+      exec:
+        command:
+        - curl - -X POST - 'http://localhost:80/'
+      initialDelaySeconds: 25
+```
+
+Be aware that this does only check the connectivity and that the port might vary. If you want a functional check as well, you could shift to an approach like the ones used for docker with the result of the [healthcheck.sh](healthcheck.sh). But I'm not a kubernetes user, so feel free to do a pull request if you have a slim approach.

healthcheck.sh

@@ -1,6 +1,10 @@
 #!/bin/sh
 
-HOST=http://localhost:80/
+if [ "$HEALTHCHECK" == "false" ]; then
+ exit 0
+fi
+
+HOST=http://127.0.0.1:${PORT}/
 TOKEN=RmVXY49YwsRfuBBfiYcWOpq6Py57pfa2x
 RESULT=$(curl -s -f -X POST -H "Content-Type: text/plain" --data "<mjml><mj-body><mj-section><mj-column><mj-text>${TOKEN}</mj-text></mj-column></mj-section></mj-body></mjml>" ${HOST})
 

index.js

@@ -23,6 +23,7 @@ const opts = {
   minify: (process.env.MJML_MINIFY === 'true'),
   beautify: (process.env.MJML_BEAUTIFY === 'true'),
   validationLevel: (['soft', 'strict', 'skip'].includes(process.env.MJML_VALIDATION_LEVEL) ? process.env.MJML_VALIDATION_LEVEL : 'soft'),
+  healthchecks: (process.env.HEALTHCHECK === 'true')
 }
 
 app.all('*', function (req, res) {
@@ -79,6 +80,7 @@ Object.keys(signals).forEach((signal) => {
 
 console.log('self: ' + os.hostname() + ':' + server.address().port)
 console.log('cors: ' + (process.env.CORS || 'n/a'))
+console.log('healthchecks: ' + opts.healthchecks)
 console.log('mjml keep comments: ' + opts.keepComments)
 console.log('mjml validation level: ' + opts.validationLevel)
 console.log('mjml minify: ' + opts.minify)