feat: add notification deduplication trigger (#14172)

coderd/database/dump.sql

@@ -223,6 +223,24 @@ CREATE TYPE workspace_transition AS ENUM (
     'delete'
 );
 
+CREATE FUNCTION compute_notification_message_dedupe_hash() RETURNS trigger
+    LANGUAGE plpgsql
+    AS $$
+BEGIN
+    NEW.dedupe_hash := MD5(CONCAT_WS(':',
+                                     NEW.notification_template_id,
+                                     NEW.user_id,
+                                     NEW.method,
+                                     NEW.payload::text,
+                                     ARRAY_TO_STRING(NEW.targets, ','),
+                                     DATE_TRUNC('day', NEW.created_at AT TIME ZONE 'UTC')::text
+                           ));
+    RETURN NEW;
+END;
+$$;
+
+COMMENT ON FUNCTION compute_notification_message_dedupe_hash() IS 'Computes a unique hash which will be used to prevent duplicate messages from being enqueued on the same day';
+
 CREATE FUNCTION delete_deleted_oauth2_provider_app_token_api_key() RETURNS trigger
     LANGUAGE plpgsql
     AS $$
@@ -678,9 +696,12 @@ CREATE TABLE notification_messages (
     updated_at timestamp with time zone,
     leased_until timestamp with time zone,
     next_retry_after timestamp with time zone,
-    queued_seconds double precision
+    queued_seconds double precision,
+    dedupe_hash text
 );
 
+COMMENT ON COLUMN notification_messages.dedupe_hash IS 'Auto-generated by insert/update trigger, used to prevent duplicate notifications from being enqueued on the same day';
+
 CREATE TABLE notification_preferences (
     user_id uuid NOT NULL,
     notification_template_id uuid NOT NULL,
@@ -1846,6 +1867,8 @@ CREATE UNIQUE INDEX idx_users_email ON users USING btree (email) WHERE (deleted
 
 CREATE UNIQUE INDEX idx_users_username ON users USING btree (username) WHERE (deleted = false);
 
+CREATE UNIQUE INDEX notification_messages_dedupe_hash_idx ON notification_messages USING btree (dedupe_hash);
+
 CREATE UNIQUE INDEX organizations_single_default_org ON organizations USING btree (is_default) WHERE (is_default = true);
 
 CREATE INDEX provisioner_job_logs_id_job_id_idx ON provisioner_job_logs USING btree (job_id, id);
@@ -1918,6 +1941,8 @@ CREATE TRIGGER trigger_update_users AFTER INSERT OR UPDATE ON users FOR EACH ROW
 
 CREATE TRIGGER trigger_upsert_user_links BEFORE INSERT OR UPDATE ON user_links FOR EACH ROW EXECUTE FUNCTION insert_user_links_fail_if_user_deleted();
 
+CREATE TRIGGER update_notification_message_dedupe_hash BEFORE INSERT OR UPDATE ON notification_messages FOR EACH ROW EXECUTE FUNCTION compute_notification_message_dedupe_hash();
+
 ALTER TABLE ONLY api_keys
     ADD CONSTRAINT api_keys_user_id_uuid_fkey FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE;