fix: don't mention retrying in the database connection error message

The PGRST000 database connection error message was "Database connection
error. Retrying the connection.", but reconnection attempts are already
logged separately by the reconnection observation, and on fatal errors
(e.g. authentication failure) PostgREST does not retry at all. Drop the
"Retrying the connection." part, leaving "Database connection error.".

CHANGELOG.md

@@ -21,6 +21,8 @@ All notable changes to this project will be documented in this file. From versio
 - Shutdown should wait for in flight requests by @mkleczek in #4702
 - Remove automatic transaction retries on `40001 (serialization_failure)` errors to prevent replication lag by @laurenceisla in #3673
 - Fix unexpected results when embedding and filtering the same table more than once by @laurenceisla in #4075
+- Fix connection retrying message in `PGRST000` error by @netqo in #4980
+  + Remove redundant "Retrying the connection." from message because it is logged separately
 
 ### Changed
 

src/PostgREST/Error.hs

@@ -475,7 +475,7 @@ instance ErrorBody SQL.UsageError where
   code    (SQL.SessionUsageError (SQL.QueryError _ _ e)) = code e
   code    SQL.AcquisitionTimeoutUsageError               = "PGRST003"
 
-  message (SQL.ConnectionUsageError _) = "Database connection error. Retrying the connection."
+  message (SQL.ConnectionUsageError _) = "Database connection error."
   message (SQL.SessionUsageError (SQL.PipelineError e))  = message e
   message (SQL.SessionUsageError (SQL.QueryError _ _ e)) = message e
   message SQL.AcquisitionTimeoutUsageError = "Timed out acquiring connection from connection pool."

test/io/test_io.py

@@ -2058,6 +2058,15 @@ def test_log_listener_connection_start(defaultenv):
         )
 
 
+def test_connection_error_message_does_not_claim_retry(defaultenv):
+    "The connection error message should not claim retrying, since PostgREST stops on fatal errors."
+    uri = f'postgresql://?dbname={defaultenv["PGDATABASE"]}&host={defaultenv["PGHOST"]}&user=some_protected_user&password=invalid_pass'
+    env = {**defaultenv, "PGRST_DB_URI": uri}
+    with run(env=env, no_startup_stdout=False, wait_for=None) as postgrest:
+        output = postgrest.read_stdout(nlines=8)
+        assert any('"message":"Database connection error."' in line for line in output)
+
+
 def test_db_pre_config_with_pg_reserved_words(defaultenv):
     "The db-pre-config should not fail unexpectedly when function name is a postgres reserved word"