fix(standalone): resolve embedded host/port at connection-build time

Windows pgserver picks a fresh ephemeral TCP port on every startup, so the
demo-DB connection row written during quick-start became stale as soon as
run-app started a new pgserver session — "Test Connection" and any target-DB
query failed with "connection refused".

Store a <embedded> sentinel in project_host instead of the live host/port;
resolve_connection_params rewrites it to the live values when standalone mode
is active. Single chokepoint covers UI test-connection, profiling, test
execution, and quick-start increments.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: aarthy-dk

testgen/commands/run_launch_db_config.py

@@ -9,7 +9,7 @@
 from testgen.common.models import with_database_session
 from testgen.common.read_file import get_template_files
 from testgen.common.read_yaml_metadata_records import import_metadata_records_from_yaml
-from testgen.common.standalone_postgres import get_target_host_port, is_standalone_mode
+from testgen.common.standalone_postgres import EMBEDDED_HOST_SENTINEL, is_standalone_mode
 
 LOG = logging.getLogger("testgen")
 
@@ -28,9 +28,10 @@ def _get_params_mapping() -> dict:
     project_user = settings.PROJECT_DATABASE_USER
     project_password = settings.PROJECT_DATABASE_PASSWORD
     if is_standalone_mode():
-        project_host, server_port = get_target_host_port()
-        if server_port:
-            project_port = server_port
+        # Live host/port are resolved at connection-build time via the sentinel
+        # so the row survives pgserver picking a fresh ephemeral port on Windows.
+        project_host = EMBEDDED_HOST_SENTINEL
+        project_port = ""
         project_user = "postgres"
         project_password = ""
 

testgen/commands/run_quick_start.py

@@ -27,7 +27,7 @@
 from testgen.common.models.table_group import TableGroup
 from testgen.common.notifications.base import smtp_configured
 from testgen.common.read_file import read_template_sql_file
-from testgen.common.standalone_postgres import get_target_host_port, is_standalone_mode
+from testgen.common.standalone_postgres import EMBEDDED_HOST_SENTINEL, is_standalone_mode
 
 LOG = logging.getLogger("testgen")
 random.seed(42)
@@ -148,9 +148,10 @@ def _get_settings_params_mapping() -> dict:
     admin_user = settings.DATABASE_ADMIN_USER
     admin_password = settings.DATABASE_ADMIN_PASSWORD
     if is_standalone_mode():
-        host, server_port = get_target_host_port()
-        if server_port:
-            port = server_port
+        # Live host/port are resolved at connection-build time via the sentinel
+        # so the row survives pgserver picking a fresh ephemeral port on Windows.
+        host = EMBEDDED_HOST_SENTINEL
+        port = ""
         admin_user = "postgres"
         admin_password = ""
 

testgen/common/database/flavor/flavor_service.py

@@ -61,13 +61,20 @@ def _decrypt_if_needed(value: Any) -> str | None:
 
 def resolve_connection_params(connection_params: ConnectionParams) -> ResolvedConnectionParams:
     sql_flavor = connection_params.get("sql_flavor") or ""
+    host = connection_params.get("project_host") or ""
+    port = connection_params.get("project_port") or ""
+    # Lazy import to keep the flavor layer free of standalone concerns at module load.
+    from testgen.common.standalone_postgres import EMBEDDED_HOST_SENTINEL, get_target_host_port, is_standalone_mode
+    if host == EMBEDDED_HOST_SENTINEL and is_standalone_mode():
+        host, live_port = get_target_host_port()
+        port = live_port or ""
     return ResolvedConnectionParams(
         url=connection_params.get("url") or "",
         connect_by_url=connection_params.get("connect_by_url", False),
         username=connection_params.get("project_user") or "",
         password=_decrypt_if_needed(connection_params.get("project_pw_encrypted")),
-        host=connection_params.get("project_host") or "",
-        port=connection_params.get("project_port") or "",
+        host=host,
+        port=port,
         dbname=connection_params.get("project_db") or "",
         dbschema=connection_params.get("table_group_schema"),
         sql_flavor=sql_flavor,

testgen/common/standalone_postgres.py

@@ -23,6 +23,13 @@
 HOME_DIR_ENV_VAR = "TG_TESTGEN_HOME"
 STANDALONE_URI_ENV_VAR = "_TG_STANDALONE_URI"
 
+# Stored as ``project_host`` in the demo-DB connection row so that the actual
+# host/port — which can change across sessions on Windows (pgserver picks a
+# fresh ephemeral TCP port each startup) — are resolved at connection-build
+# time by ``resolve_connection_params``. Angle brackets are illegal in real
+# hostnames, so this can't collide with a user-defined connection.
+EMBEDDED_HOST_SENTINEL = "<embedded>"
+
 
 def get_home_dir() -> Path:
     env_dir = os.getenv(HOME_DIR_ENV_VAR)