[*] сleanup pgbackrest helper function by cybertec-postgresql/pgwatch…

…2#512

src/metrics/00_helpers/get_backup_age_pgbackrest/11/metric.sql

@@ -0,0 +1,48 @@
+CREATE EXTENSION IF NOT EXISTS plpython3u;
+/*
+  Gets age of last successful pgBackRest backup via "pgbackrest --output=json info" unix timestamp. Returns 0 retcode on success.
+  Expects pgBackRest is correctly configured on monitored DB and "jq" tool is installed on the DB server.
+*/
+CREATE OR REPLACE FUNCTION get_backup_age_pgbackrest(OUT retcode int, OUT backup_age_seconds int, OUT message text) AS
+$$
+import time
+import json
+import subprocess
+
+PGBACKREST_TIMEOUT = 30
+
+def error(message, returncode=1):
+  return returncode, 1000000, 'Not OK. '+message
+
+pgbackrest_cmd=["pgbackrest", "--output=json", "info"]
+
+try:
+    p = subprocess.Popen(pgbackrest_cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, encoding='utf-8')
+    stdout, stderr = p.communicate(timeout=PGBACKREST_TIMEOUT)
+except OSError as e:
+    return error('Failed to execute pgbackrest: {}'.format(e))
+except subprocess.TimeoutExpired:
+    p.terminate()
+    try:
+        p.wait(0.5)
+    except subprocess.TimeoutExpired:
+        p.kill()
+    return error('pgbackrest failed to respond in {} seconds'.format(PGBACKREST_TIMEOUT))
+
+if p.returncode != 0:
+    return error('Failed on "pgbackrest info" call', returncode=p.returncode)
+
+try:
+    data = json.loads(stdout)
+    backup_age_seconds = int(time.time()) - data[0]['backup'][-1]['timestamp']['stop']
+    return 0, backup_age_seconds, 'OK. Last backup age in seconds: {}'.format(backup_age_seconds)
+except (json.JSONDecodeError, KeyError) :
+    return error('Failed to parse pgbackrest output')
+$$ LANGUAGE plpython3u VOLATILE;
+
+/* contacting S3 could be laggy depending on location */
+ALTER FUNCTION get_backup_age_pgbackrest() SET statement_timeout TO '30s';
+
+GRANT EXECUTE ON FUNCTION get_backup_age_pgbackrest() TO pgwatch2;
+
+COMMENT ON FUNCTION get_backup_age_pgbackrest() is 'created for pgwatch2';