feat: 🎉 postgresql broker first commit of forked prototype from my original code

pkg/broker/install/sql/procedures/01_broker_get.sql

@@ -0,0 +1,76 @@
+-- broker_get function
+-- Fetches the next job from the queue for a given queue number
+-- Returns: p_retval (0=success, >0=error), p_errmsg (error message), p_job_id (job ID if found)
+
+CREATE OR REPLACE FUNCTION broker_get(
+    p_queue_number INTEGER,
+    p_instance_id BIGINT DEFAULT NULL,
+    OUT p_retval INTEGER,
+    OUT p_errmsg TEXT,
+    OUT p_job_id BIGINT
+)
+RETURNS RECORD
+LANGUAGE plpgsql
+AS $$
+DECLARE
+    v_job_record RECORD;
+BEGIN
+    p_retval := 0;
+    p_errmsg := '';
+    p_job_id := NULL;
+
+    -- Validate queue number
+    IF p_queue_number IS NULL OR p_queue_number <= 0 THEN
+        p_retval := 1;
+        p_errmsg := 'Invalid queue number';
+        RETURN;
+    END IF;
+
+    -- Find and lock the next pending job for this queue
+    -- Uses SKIP LOCKED to avoid blocking on jobs being processed by other workers
+    -- Skip jobs with pending dependencies
+    SELECT id_broker_jobs, job_name, job_priority, execute_str
+    INTO v_job_record
+    FROM broker_jobs
+    WHERE job_queue = p_queue_number
+      AND complete_status = 0  -- pending
+      AND (
+        depends_on IS NULL  -- no dependencies
+        OR depends_on = '{}'  -- empty dependencies
+        OR NOT EXISTS (  -- all dependencies completed
+          SELECT 1
+          FROM broker_jobs dep
+          WHERE dep.job_name = ANY(broker_jobs.depends_on)
+            AND dep.complete_status = 0  -- pending dependency
+        )
+      )
+    ORDER BY job_priority DESC, created_at ASC
+    LIMIT 1
+    FOR UPDATE SKIP LOCKED;
+
+    -- If no job found, return success with NULL job_id
+    IF NOT FOUND THEN
+        RETURN;
+    END IF;
+
+    -- Update job status to running
+    UPDATE broker_jobs
+    SET complete_status = 1,  -- running
+        started_at = NOW(),
+        rid_broker_queueinstance = p_instance_id,
+        updated_at = NOW()
+    WHERE id_broker_jobs = v_job_record.id_broker_jobs;
+
+    -- Return the job ID
+    p_job_id := v_job_record.id_broker_jobs;
+
+EXCEPTION
+    WHEN OTHERS THEN
+        p_retval := 2;
+        p_errmsg := SQLERRM;
+        RAISE WARNING 'broker_get error: %', SQLERRM;
+END;
+$$;
+
+-- Comments
+COMMENT ON FUNCTION broker_get IS 'Fetches the next pending job from the specified queue';