From 20be426125d1aa1f52a276177565a98a2eba0929 Mon Sep 17 00:00:00 2001
From: Jose Diaz-Gonzalez <email@josediazgonzalez.com>
Date: Sun, 21 Sep 2025 19:10:01 -0400
Subject: [PATCH] feat: add support for locking in docker-local commands

---
 plugins/cron/cron.go                         |  2 +-
 plugins/run/internal-functions               | 17 ++++++++-
 plugins/scheduler-docker-local/scheduler-run | 39 ++++++++++++++++++++
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/plugins/cron/cron.go b/plugins/cron/cron.go
index aa62ed75c..89d19f552 100644
--- a/plugins/cron/cron.go
+++ b/plugins/cron/cron.go
@@ -75,7 +75,7 @@ func (t CronTask) DokkuRunCommand() string {
 		return t.AltCommand
 	}
 
-	return fmt.Sprintf("dokku run --cron-id %s %s %s", t.ID, t.App, t.Command)
+	return fmt.Sprintf("dokku run --concurrency-policy %s --cron-id %s %s %s", t.ConcurrencyPolicy, t.ID, t.App, t.Command)
 }
 
 // FetchCronTasksInput is the input for the FetchCronTasks function
diff --git a/plugins/run/internal-functions b/plugins/run/internal-functions
index b4ccfc2ce..fe45b1790 100755
--- a/plugins/run/internal-functions
+++ b/plugins/run/internal-functions
@@ -9,7 +9,7 @@ fn-run() {
   shift 1
 
   declare APP=""
-  local CRON_ID
+  local CRON_ID CONCURRENCY_POLICY="allow"
   declare -a RUN_ENV
   RUN_ENV=()
   while [[ $# -gt 0 ]]; do
@@ -19,6 +19,11 @@ fn-run() {
         CRON_ID="$arg"
         shift
         ;;
+      --concurrency-policy=*)
+        local arg=$(printf "%s" "$1" | sed -E 's/(^--concurrency-policy=)//g')
+        CONCURRENCY_POLICY="$arg"
+        shift
+        ;;
       --no-tty)
         export DOKKU_DISABLE_TTY=true
         shift
@@ -35,6 +40,14 @@ fn-run() {
         CRON_ID="$2"
         shift 2
         ;;
+      --concurrency-policy)
+        if [[ ! $2 ]]; then
+          dokku_log_warn "expected $1 to have an argument"
+          break
+        fi
+        CONCURRENCY_POLICY="$2"
+        shift 2
+        ;;
       -e=* | --env=*)
         local arg=$(printf "%s" "$1" | sed -E 's/(^-e=)|(^--env=)//g')
         RUN_ENV+=("$arg")
@@ -67,7 +80,7 @@ fn-run() {
   verify_app_name "$APP"
 
   local DOKKU_SCHEDULER=$(get_app_scheduler "$APP")
-  DOKKU_CRON_ID="$CRON_ID" plugn trigger scheduler-run "$DOKKU_SCHEDULER" "$APP" "${#RUN_ENV[@]}" "${RUN_ENV[@]}" -- "$@"
+  DOKKU_CRON_ID="$CRON_ID" DOKKU_CONCURRENCY_POLICY="$CONCURRENCY_POLICY" plugn trigger scheduler-run "$DOKKU_SCHEDULER" "$APP" "${#RUN_ENV[@]}" "${RUN_ENV[@]}" -- "$@"
 }
 
 cmd-run() {
diff --git a/plugins/scheduler-docker-local/scheduler-run b/plugins/scheduler-docker-local/scheduler-run
index cb6bbfb74..096210dc3 100755
--- a/plugins/scheduler-docker-local/scheduler-run
+++ b/plugins/scheduler-docker-local/scheduler-run
@@ -5,6 +5,25 @@ source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
 source "$PLUGIN_AVAILABLE_PATH/config/functions"
 source "$PLUGIN_AVAILABLE_PATH/scheduler-docker-local/internal-functions"
 
+fn-scheduler-docker-local-scheduler-run-acquire-lock() {
+  declare desc="acquire advisory lock for use in docker-local cron jobs"
+  local APP="$1" CRON_ID="$2"
+  local LOCK_TYPE="exclusive"
+  local APP_DEPLOY_LOCK_FILE="$DOKKU_LIB_ROOT/data/scheduler-docker-local/$APP/cron-$CRON_ID.lock"
+  local LOCK_WAITING_MSG="$APP currently has a cron lock in place for $CRON_ID. Waiting..."
+  local LOCK_FAILED_MSG="$APP currently has a cron lock in place for $CRON_ID. Exiting..."
+
+  acquire_advisory_lock "$APP_DEPLOY_LOCK_FILE" "$LOCK_TYPE" "$LOCK_WAITING_MSG" "$LOCK_FAILED_MSG"
+}
+
+fn-scheduler-docker-local-scheduler-run-release-lock() {
+  declare desc="release advisory lock used in docker-local cron jobs"
+  local APP="$1" CRON_ID="$2"
+  local APP_DEPLOY_LOCK_FILE="$DOKKU_LIB_ROOT/data/scheduler-docker-local/$APP/cron-$CRON_ID.lock"
+
+  release_advisory_lock "$APP_DEPLOY_LOCK_FILE"
+}
+
 trigger-scheduler-docker-local-scheduler-run() {
   declare desc="runs command in container based on app image"
   declare trigger="scheduler-run"
@@ -39,9 +58,24 @@ trigger-scheduler-docker-local-scheduler-run() {
   [[ "$DOKKU_TRACE" ]] && DOCKER_ARGS+=" -e TRACE=true "
 
   local PROCESS_TYPE=run
+  local concurrency_policy="allow"
   if [[ -n "$DOKKU_CRON_ID" ]]; then
     PROCESS_TYPE=cron
     DOCKER_ARGS+=" --label=com.dokku.cron-id=$DOKKU_CRON_ID"
+
+    if [[ -n "$DOKKU_CONCURRENCY_POLICY" ]]; then
+      concurrency_policy="$DOKKU_CONCURRENCY_POLICY"
+    fi
+    concurrency_policy="$DOKKU_CONCURRENCY_POLICY"
+    DOCKER_ARGS+=" --label=com.dokku.concurrency-policy=$concurrency_policy"
+
+    if [[ "$concurrency_policy" == "forbid" ]]; then
+      fn-scheduler-docker-local-scheduler-run-acquire-lock "$APP" "$DOKKU_CRON_ID"
+    fi
+
+    if [[ "$concurrency_policy" == "replace" ]]; then
+      dokku_log_warn "Concurrency policy 'replace' is not supported for docker-local cron jobs"
+    fi
   fi
 
   local DYNO_NUMBER="$RANDOM"
@@ -138,6 +172,11 @@ trigger-scheduler-docker-local-scheduler-run() {
     DOKKU_CONTAINER_EXIT_CODE="$("$DOCKER_BIN" container wait "$CONTAINER_ID" 2>/dev/null || echo "$EXIT_CODE")"
     [[ -z "$DOKKU_CONTAINER_EXIT_CODE" ]] && DOKKU_CONTAINER_EXIT_CODE=0
   fi
+
+  if [[ -n "$DOKKU_CRON_ID" ]] && [[ "$concurrency_policy" == "forbid" ]]; then
+    fn-scheduler-docker-local-scheduler-run-release-lock "$APP" "$DOKKU_CRON_ID"
+  fi
+
   plugn trigger scheduler-post-run "$DOKKU_SCHEDULER" "$APP" "$CONTAINER_ID" "$DOKKU_CONTAINER_EXIT_CODE"
   return "$DOKKU_CONTAINER_EXIT_CODE"
 }