Reduce preview PR comment size

Dockerfile

@@ -10,7 +10,5 @@ LABEL "com.github.actions.color"="yellow"
 
 RUN apk add --no-cache bash
 
-COPY README.md /
-
-COPY entrypoint.sh /entrypoint.sh
+COPY README.md entrypoint.sh bin/filter-preview-output.sh /
 ENTRYPOINT ["/entrypoint.sh"]

README.md

@@ -105,7 +105,7 @@ GitHub Action.
   with:
     msg: |
       ```
-      ${{ steps.dnscontrol_preview.outputs.output }}
+      ${{ steps.dnscontrol_preview.outputs.preview_comment }}
       ```
     check_for_duplicate_msg: true
 ```

bin/filter-preview-output.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# source: https://git.io/J86QD
+grep -v -e '^\.\.\.0 corrections$' |\
+  grep -v -e '^0 corrections' |\
+  grep -v -e '\.\.\. (skipping)' |\
+  grep -v -e '^----- DNS Provider: ' |\
+  grep -v -e '^----- Registrar: ' |\
+  grep -v -e '^----- Getting nameservers from:'

entrypoint.sh

@@ -30,5 +30,10 @@ OUTPUT="${OUTPUT//'%'/'%25'}"
 OUTPUT="${OUTPUT//$'\n'/'%0A'}"
 OUTPUT="${OUTPUT//$'\r'/'%0D'}"
 
+# Filter output to reduce 'preview' PR comment length
+FILTERED_OUTPUT="$(echo "$OUTPUT" | /filter-preview-output.sh)"
+
 echo "::set-output name=output::$OUTPUT"
+echo "::set-output name=preview_comment::$FILTERED_OUTPUT"
+
 exit $EXIT_CODE