fix: clarify "listening" logs

It's not immediately clear on which port the API server is listening.
Also it's not clear that the "pgrst" channel is for database
notifications.

Goes from:

<timestamp>: Admin server listening on 0.0.0.0:3001
<timestamp>: Listening on 0.0.0.0:3000
<timestamp>: Listening for notifications on the "pgrst" channel

To:

<timestamp>: Admin server listening on 0.0.0.0:3001
<timestamp>: API server listening on 0.0.0.0:3000
<timestamp>: Listening for database notifications on the "pgrst" channel

CHANGELOG.md

@@ -20,6 +20,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
  - #3693, Fix spread embedding errors when using the `count()` aggregate without a field - @laurenceisla
    + Fixed `"column reference <col> is ambiguous"` error when selecting `?select=...table(col,count())`
    + Fixed `"column <json_aggregate>.<alias> does not exist"` error when selecting `?select=...table(aias:count())`
+ - #3727, Clarify "listening" logs - @steve-chavez
 
 ### Changed
 

docs/references/observability.rst

@@ -33,8 +33,8 @@ For diagnostic information about the server itself, PostgREST logs to ``stderr``
    06/May/2024:08:16:11 -0500: Starting PostgREST 12.1...
    06/May/2024:08:16:11 -0500: Attempting to connect to the database...
    06/May/2024:08:16:11 -0500: Successfully connected to PostgreSQL 14.10 (Ubuntu 14.10-0ubuntu0.22.04.1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, 64-bit
-   06/May/2024:08:16:11 -0500: Listening on port 3000
-   06/May/2024:08:16:11 -0500: Listening for notifications on the "pgrst" channel
+   06/May/2024:08:16:11 -0500: API server listening on port 3000
+   06/May/2024:08:16:11 -0500: Listening for database notifications on the "pgrst" channel
    06/May/2024:08:16:11 -0500: Config reloaded
    06/May/2024:08:16:11 -0500: Schema cache queried in 3.8 milliseconds
    06/May/2024:08:16:11 -0500: Schema cache loaded 15 Relations, 8 Relationships, 8 Functions, 0 Domain Representations, 4 Media Type Handlers

src/PostgREST/Observation.hs

@@ -65,9 +65,9 @@ observationMessage = \case
   AppStartObs ver ->
     "Starting PostgREST " <> T.decodeUtf8 ver <> "..."
   AppServerPortObs host port ->
-    "Listening on " <> host <> ":" <> show port
+    "API server listening on " <> host <> ":" <> show port
   AppServerUnixObs sock ->
-    "Listening on unix socket " <> show sock
+    "API server listening on unix socket " <> show sock
   DBConnectedObs ver ->
     "Successfully connected to " <> ver
   ExitUnsupportedPgVersion pgVer minPgVer ->
@@ -95,15 +95,15 @@ observationMessage = \case
   QueryPgVersionError usageErr ->
     "Failed to query the PostgreSQL version. " <> jsonMessage usageErr
   DBListenStart channel -> do
-    "Listening for notifications on the " <> show channel <> " channel"
+    "Listening for database notifications on the " <> show channel <> " channel"
   DBListenFail channel listenErr ->
-    "Failed listening for notifications on the " <> show channel <> " channel. " <> (
+    "Failed listening for database notifications on the " <> show channel <> " channel. " <> (
       case listenErr of
         Left err  -> show err
         Right err -> showListenerError err
     )
   DBListenRetry delay ->
-    "Retrying listening for notifications in " <> (show delay::Text) <> " seconds..."
+    "Retrying listening for database notifications in " <> (show delay::Text) <> " seconds..."
   DBListenerGotSCacheMsg channel ->
     "Received a schema cache reload message on the " <> show channel <> " channel"
   DBListenerGotConfigMsg channel ->

test/io/test_io.py

@@ -1268,7 +1268,7 @@ def test_log_postgrest_host_and_port(defaultenv):
     ) as postgrest:
         output = postgrest.read_stdout(nlines=10)
 
-        assert f"Listening on {host}:{port}" in output[2]  # output-sensitive
+        assert f"API server listening on {host}:{port}" in output[2]  # output-sensitive
 
 
 def test_succeed_w_role_having_superuser_settings(defaultenv):