Add script for automatic release pruning

.github/workflows/build.yml

@@ -114,3 +114,7 @@ jobs:
           hub release create $(for a in artifacts/*; do echo -a $a; done) -m "$NAME" -t "master" "$TAGNAME"
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Prune old releases
+        run: ./util/prunetags.sh
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

util/prunetags.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+set -e
+git fetch --tags
+TAGS=( $(git tag -l "autobuild-*" | sort -r) )
+
+KEEP_LATEST=14
+KEEP_MONTHLY=12
+
+LATEST_TAGS=()
+MONTHLY_TAGS=()
+
+CUR_MONTH="-1"
+
+for TAG in ${TAGS[@]}; do
+    if [[ ${#LATEST_TAGS[@]} -lt ${KEEP_LATEST} ]]; then
+        LATEST_TAGS+=( "$TAG" )
+    fi
+
+    if [[ ${#MONTHLY_TAGS[@]} -lt ${KEEP_MONTHLY} ]]; then
+        TAG_MONTH="$(echo $TAG | cut -d- -f3)"
+
+        if [[ ${TAG_MONTH} != ${CUR_MONTH} ]]; then
+            CUR_MONTH="${TAG_MONTH}"
+            MONTHLY_TAGS+=( "$TAG" )
+        fi
+    fi
+done
+
+for TAG in ${LATEST_TAGS[@]} ${MONTHLY_TAGS[@]}; do
+    TAGS=( "${TAGS[@]/$TAG}" )
+done
+
+for TAG in ${TAGS[@]}; do
+    echo "Deleting ${TAG}"
+    hub release delete "${TAG}"
+    git tag -d "${TAG}"
+done
+
+git push --tags --prune