.github: nightly purge of old pipelines from certain branches

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/scripts/gh-purge-pipelines.sh

@@ -0,0 +1,112 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+    echo "Usage: $0 --org ORG --repo REPO --branch BRANCH --keep N [--dry-run] [--debug]"
+    exit 1
+}
+
+log_info() { echo "[INFO] $*"; }
+log_warn() { echo "[WARN] $*" >&2; }
+log_error() { echo "[ERROR] $*" >&2; }
+
+ORG=""
+REPO=""
+BRANCH=""
+KEEP=0
+DRY_RUN=0
+DEBUG=0
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --org) ORG="$2"; shift 2 ;;
+        --repo) REPO="$2"; shift 2 ;;
+        --branch) BRANCH="$2"; shift 2 ;;
+        --keep) KEEP="$2"; shift 2 ;;
+        --dry-run) DRY_RUN=1; shift ;;
+        --debug) DEBUG=1; shift ;;
+        *) usage ;;
+    esac
+done
+
+if [[ -z "$ORG" || -z "$REPO" || -z "$BRANCH" || "$KEEP" -le 0 ]]; then
+    usage
+fi
+
+if ! command -v gh >/dev/null 2>&1; then
+    log_error "GitHub CLI 'gh' is required but not found"
+    exit 1
+fi
+
+if [[ $DEBUG -eq 1 ]]; then
+    set -x
+fi
+
+log_info "Fetching runs for $ORG/$REPO on branch $BRANCH ..."
+
+runs=$(
+    gh api \
+        -H "Accept: application/vnd.github+json" \
+        "/repos/$ORG/$REPO/actions/runs?branch=$BRANCH&per_page=100" \
+        --jq '.workflow_runs[] | "\(.id)|\(.run_number)|\(.conclusion)|\(.created_at)"' |
+        sort -t'|' -k2,2nr
+)
+
+mapfile -t entries <<<"$runs"
+
+declare -A keep
+
+# keep N most recent
+count=0
+for entry in "${entries[@]}"; do
+    ((count++)) || true
+    run_id="${entry%%|*}"
+    if ((count <= KEEP)); then
+        keep["$run_id"]=1
+    fi
+done
+
+# helper to find neighbor entry (previous/next successful)
+get_neighbor_entry() {
+    local idx="$1"
+    local direction="$2" # -1 for previous, +1 for next
+    local new_idx=$((idx + direction))
+    if ((new_idx >= 0 && new_idx < ${#entries[@]})); then
+        echo "${entries[$new_idx]}"
+    fi
+}
+
+# find broken runs and mark them + neighbors
+for idx in "${!entries[@]}"; do
+    IFS='|' read -r run_id number conclusion created <<<"${entries[$idx]}"
+    jobs=$(gh run view "$run_id" -R "$ORG/$REPO" --json jobs \
+               --template '{{range .jobs}}{{.conclusion}}{{"\n"}}{{end}}')
+    if echo "$jobs" | grep -qE 'failure|cancelled|timed_out'; then
+        keep["$run_id"]=1
+        for dir in -1 1; do
+            neighbor=$(get_neighbor_entry "$idx" "$dir" || true)
+            if [[ -n "$neighbor" ]]; then
+                IFS='|' read -r n_id n_num n_conc n_created <<<"$neighbor"
+                if [[ "$n_conc" == "success" ]]; then
+                    keep["$n_id"]=1
+                fi
+            fi
+        done
+    fi
+done
+
+# decide what to keep/delete
+for entry in "${entries[@]}"; do
+    IFS='|' read -r run_id number conclusion created <<<"$entry"
+    if [[ -n "${keep[$run_id]:-}" ]]; then
+        log_info "KEEP   run_id=$run_id number=$number status=$conclusion created=$created"
+    else
+        if [[ "$DRY_RUN" -eq 1 ]]; then
+            log_info "Would delete run $run_id ($number)"
+        else
+            log_info "Deleting run $run_id ($number)"
+            gh api --method DELETE -H "Accept: application/vnd.github+json" \
+                "/repos/$ORG/$REPO/actions/runs/$run_id" || true
+        fi
+    fi
+done