feat(hasura): remove old alerts (#339)

README-dev.md

@@ -155,6 +155,15 @@ select audit.audit_table('documents',
 
 Pour voir la [configuration du trigger](targets/hasura/migrations/1613474820206_audit_trigger/up.sql)
 
+## Suppression des données anciennes
+
+Les données de certaines tables sont nettoyées automatiquement.
+
+Pour l'instant seulement 2 triggers sont en place:
+
+- nettoyage de la table `alerts` (alertes traitées conservés pour 3mois)
+- nettoyage de la table `audit.logged_action` (actions conservées pour 3mois)
+
 ## How to ?
 
 ### How to retrieve CDTN data from production ?

targets/hasura/migrations/1613499638772_alert_clean/down.sql

@@ -0,0 +1,2 @@
+DROP TRIGGER IF EXISTS delete_alerts on alerts;
+DROP FUNCTION IF EXISTS delete_old_alerts;

targets/hasura/migrations/1613499638772_alert_clean/up.sql

@@ -0,0 +1,20 @@
+CREATE OR REPLACE FUNCTION delete_old_alerts() RETURNS trigger AS $body$
+BEGIN
+  DELETE FROM alerts WHERE created_at < NOW() - TG_ARGV[0]::integer * interval'1 month' AND status IN ('done', 'rejected');
+  RETURN NULL;
+END;
+$body$
+LANGUAGE 'plpgsql';
+
+COMMENT ON FUNCTION delete_old_alerts(duration) IS $body$
+Remove alerts that are older that a given duration
+
+Arguments:
+  duration: duration in month until alerts are dropped
+$body$;
+
+CREATE TRIGGER delete_alerts AFTER INSERT OR UPDATE ON alerts
+FOR EACH STATEMENT EXECUTE PROCEDURE delete_old_alerts(3);
+
+COMMENT ON TRIGGER "delete_alerts" ON alerts
+  IS 'trigger to remove alert that older than 3 monthes';