add --postgrest-query-cost-limit option 📝

Author: derhuerst

cli.js

@@ -71,6 +71,9 @@ const {
 		'postgrest-password': {
 			type: 'string',
 		},
+		'postgrest-query-cost-limit': {
+			type: 'string',
+		},
 		'import-metadata': {
 			type: 'boolean',
 		}
@@ -135,6 +138,12 @@ Options:
                                     https://postgrest.org/
     --postgrest-password          Password for the PostgREST PostgreSQL user \`web_anon\`.
                                     Default: $POSTGREST_PGPASSWORD, fallback random.
+    --postgrest-query-cost-limit  Define a cost limit [1] for queries executed by PostgREST
+                                    on behalf of a user. It is only enforced if
+                                    pg_plan_filter [2] is installed in the database!
+                                    Must be a positive float. Default: none
+                                    [1] https://www.postgresql.org/docs/14/using-explain.html
+                                    [2] https://github.com/pgexperts/pg_plan_filter
     --import-metadata             Create functions returning import metadata:
                                     - gtfs_data_imported_at (timestamp with time zone)
                                     - gtfs_via_postgres_version (text)
@@ -192,6 +201,14 @@ if ('postgraphile-password' in flags) {
 if ('postgrest-password' in flags) {
 	opt.postgrestPassword = flags['postgrest-password']
 }
+if ('postgrest-query-cost-limit' in flags) {
+	const limit = parseFloat(flags['postgrest-query-cost-limit'])
+	if (!Number.isFinite(limit) || limit < 0) {
+		console.error('Invalid --postgrest-query-cost-limit value.')
+		process.exit(1)
+	}
+	opt.lowerCaseLanguageCodes = limit
+}
 
 pipeline(
 	convertGtfsToSql(files, opt),

index.js

@@ -29,6 +29,9 @@ const convertGtfsToSql = async function* (files, opt = {}) {
 		postgraphilePassword: process.env.POSTGRAPHILE_PGPASSWORD || null,
 		postgrest: false,
 		postgrestPassword: process.env.POSTGREST_PASSWORD || null,
+		// see https://github.com/pgexperts/pg_plan_filter
+		// see also https://www.postgresql.org/docs/14/using-explain.html
+		postgrestQueryCostLimit: null, // or float
 		importMetadata: false,
 		...opt,
 	}
@@ -345,6 +348,11 @@ GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA "${opt.schema}" TO web_anon;
 
 GRANT web_anon TO postgrest;
 
+${opt.postgrestQueryCostLimit !== null ? `
+-- If pg_plan_filter is installed, limit the cost of queries made by PostgREST users.
+ALTER USER web_anon SET plan_filter.statement_cost_limit = ${opt.postgrestQueryCostLimit};
+` : ''}
+
 COMMENT ON SCHEMA "${opt.schema}" IS
 $$GTFS REST API
 This REST API is created by running [PostgREST](https://postgrest.org/) on top of a [PostgreSQL](https://www.postgresql.org) DB generated using [gtfs-via-postgres](https://github.com/public-transport/gtfs-via-postgres).

readme.md

@@ -194,6 +194,12 @@ Options:
                                     https://postgrest.org/
     --postgrest-password          Password for the PostgREST PostgreSQL user `web_anon`.
                                     Default: $POSTGREST_PGPASSWORD, fallback random.
+    --postgrest-query-cost-limit  Define a cost limit [1] for queries executed by PostgREST
+                                    on behalf of a user. It is only enforced if
+                                    pg_plan_filter [2] is installed in the database!
+                                    Must be a positive float. Default: none
+                                    [1] https://www.postgresql.org/docs/14/using-explain.html
+                                    [2] https://github.com/pgexperts/pg_plan_filter
     --import-metadata             Create functions returning import metadata:
                                     - gtfs_data_imported_at (timestamp with time zone)
                                     - gtfs_via_postgres_version (text)