From c85f68ae230d095a66f95aa01789b5346d2441fc Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Fri, 23 Apr 2021 01:29:53 +0100
Subject: [PATCH] Add ConnectionInfo.error_message, backend_pid

---
 docs/api/connections.rst      |  3 +++
 psycopg3/psycopg3/conninfo.py | 16 ++++++++++++++++
 tests/test_conninfo.py        | 20 ++++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/docs/api/connections.rst b/docs/api/connections.rst
index 566fbd069..7590e8ff0 100644
--- a/docs/api/connections.rst
+++ b/docs/api/connections.rst
@@ -273,6 +273,9 @@ Connection support objects
         server and not yet completed.
 
     .. autoattribute:: server_version
+    .. autoattribute:: backend_pid
+    .. autoattribute:: error_message
+
     .. automethod:: get_parameters
     .. autoattribute:: host
 
diff --git a/psycopg3/psycopg3/conninfo.py b/psycopg3/psycopg3/conninfo.py
index 94d6149e4..b2171b683 100644
--- a/psycopg3/psycopg3/conninfo.py
+++ b/psycopg3/psycopg3/conninfo.py
@@ -201,6 +201,14 @@ class ConnectionInfo:
         """
         return self.pgconn.server_version
 
+    @property
+    def backend_pid(self) -> int:
+        """
+        The process ID (PID) of the backend process handling this connection.
+        See :pq:`PQbackendPID`.
+        """
+        return self.pgconn.backend_pid
+
     @property
     def protocol_version(self) -> int:
         """
@@ -208,6 +216,14 @@ class ConnectionInfo:
         """
         return self.pgconn.protocol_version
 
+    @property
+    def error_message(self) -> str:
+        """
+        The error message most recently generated by an operation on the connection.
+        See :pq:`PQerrorMessage`.
+        """
+        return self._get_pgconn_attr("error_message")
+
     def _get_pgconn_attr(self, name: str) -> str:
         value: bytes = getattr(self.pgconn, name)
         return value.decode(self._pyenc)
diff --git a/tests/test_conninfo.py b/tests/test_conninfo.py
index 64c75ef45..ff5e9544e 100644
--- a/tests/test_conninfo.py
+++ b/tests/test_conninfo.py
@@ -160,3 +160,23 @@ class TestConnectionInfo:
 
     def test_protocol_version(self, conn):
         assert conn.info.protocol_version >= 3
+
+    def test_error_message(self, conn):
+        assert conn.info.error_message == ""
+        with pytest.raises(psycopg3.ProgrammingError) as ex:
+            conn.execute("wat")
+
+        assert conn.info.error_message
+        assert str(ex.value) in conn.info.error_message
+        assert ex.value.diag.severity in conn.info.error_message
+
+        conn.close()
+        with pytest.raises(psycopg3.OperationalError):
+            conn.info.error_message
+
+    def test_backend_pid(self, conn):
+        assert conn.info.backend_pid
+        assert conn.info.backend_pid == conn.pgconn.backend_pid
+        conn.close()
+        with pytest.raises(psycopg3.OperationalError):
+            conn.info.backend_pid
-- 
2.47.2