add POSTGRES_USE_READ_ONLY flag to disable using read only replica

Signed-off-by: Amit Prinz Setter <[email protected]>

Author: alphaprinz

config.js

@@ -251,6 +251,10 @@ config.DB_TYPE = /** @type {nb.DBType} */ (process.env.DB_TYPE || 'postgres');
 config.POSTGRES_DEFAULT_MAX_CLIENTS = 10;
 config.POSTGRES_MD_MAX_CLIENTS = (process.env.LOCAL_MD_SERVER === 'true') ? 70 : 10;
 
+//whether to use read-only postgres replica cluster
+//ro host is set by operator in process.env.POSTGRES_HOST_RO
+config.POSTGRES_USE_READ_ONLY = true;
+
 ///////////////////
 // SYSTEM CONFIG //
 ///////////////////

src/util/postgres_client.js

@@ -1525,7 +1525,11 @@ class PostgresClient extends EventEmitter {
             // get the connection configuration. first from env, then from file, then default
             const host = process.env.POSTGRES_HOST || fs_utils.try_read_file_sync(process.env.POSTGRES_HOST_PATH) || '127.0.0.1';
             //optional read-only host. if not present defaults to general pg host
-            const host_ro = process.env.POSTGRES_HOST_RO || fs_utils.try_read_file_sync(process.env.POSTGRES_HOST_RO_PATH) || host;
+            let host_ro = process.env.POSTGRES_HOST_RO || fs_utils.try_read_file_sync(process.env.POSTGRES_HOST_RO_PATH) || host;
+            //if POSTGRES_USE_READ_ONLY is off, switch to regular host
+            if (!config.POSTGRES_USE_READ_ONLY) {
+                host_ro = host;
+            }
             const user = process.env.POSTGRES_USER || fs_utils.try_read_file_sync(process.env.POSTGRES_USER_PATH) || 'postgres';
             const password = process.env.POSTGRES_PASSWORD || fs_utils.try_read_file_sync(process.env.POSTGRES_PASSWORD_PATH) || 'noobaa';
             const database = process.env.POSTGRES_DBNAME || fs_utils.try_read_file_sync(process.env.POSTGRES_DBNAME_PATH) || 'nbcore';