Set session timezone to local timezone on startup

AUTHORS

@@ -137,6 +137,7 @@ Contributors:
     * Chris Rose (offbyone/offby1)
     * Mathieu Dupuy (deronnax)
     * Chris Novakovic
+    * Max Smolin (maximsmol)
     * Josh Lynch (josh-lynch)
     * Fabio (3ximus)
 

changelog.rst

@@ -1,3 +1,10 @@
+Dev
+==================
+
+Features
+--------
+* The session time zone setting is set to the system time zone by default
+
 4.2.0 (2025-03-06)
 ==================
 

pgcli/main.py

@@ -1,3 +1,4 @@
+from zoneinfo import ZoneInfoNotFoundError
 from configobj import ConfigObj, ParseError
 from pgspecial.namedqueries import NamedQueries
 from .config import skip_initial_comment
@@ -23,6 +24,7 @@
 from cli_helpers.utils import strip_ansi
 from .explain_output_formatter import ExplainOutputFormatter
 import click
+import tzlocal
 
 try:
     import setproctitle
@@ -1593,9 +1595,9 @@ def cli(
     if list_databases or ping_database:
         database = "postgres"
 
+    cfg = load_config(pgclirc, config_full_path)
     if dsn != "":
         try:
-            cfg = load_config(pgclirc, config_full_path)
             dsn_config = cfg["alias_dsn"][dsn]
         except KeyError:
             click.secho(
@@ -1624,6 +1626,55 @@ def cli(
     else:
         pgcli.connect(database, host, user, port)
 
+    if "use_local_timezone" not in cfg["main"] or cfg["main"].as_bool(
+        "use_local_timezone"
+    ):
+        server_tz = pgcli.pgexecute.get_timezone()
+
+        def echo_error(msg: str):
+            click.secho(
+                "Failed to determine the local time zone",
+                err=True,
+                fg="yellow",
+            )
+            click.secho(
+                msg,
+                err=True,
+                fg="yellow",
+            )
+            click.secho(
+                f"Continuing with the default time zone as preset by the server ({server_tz})",
+                err=True,
+                fg="yellow",
+            )
+            click.secho(
+                "Set `use_local_timezone = False` in the config to avoid trying to override the server time zone\n",
+                err=True,
+                dim=True,
+            )
+
+        local_tz = None
+        try:
+            local_tz = tzlocal.get_localzone_name()
+
+            if local_tz is None:
+                echo_error("No local time zone configuration found\n")
+            else:
+                click.secho(
+                    f"Using local time zone {local_tz} (server uses {server_tz})",
+                    fg="green",
+                )
+                click.secho(
+                    "Use `set time zone <TZ>` to override, or set `use_local_timezone = False` in the config",
+                    dim=True,
+                )
+
+                pgcli.pgexecute.set_timezone(local_tz)
+        except ZoneInfoNotFoundError as e:
+            # e.args[0] is the pre-formatted message which includes a list
+            # of conflicting sources
+            echo_error(e.args[0])
+
     if list_databases:
         cur, headers, status = pgcli.pgexecute.full_databases()
 

pgcli/pgclirc

@@ -191,6 +191,10 @@ enable_pager = True
 # Use keyring to automatically save and load password in a secure manner
 keyring = True
 
+# Automatically set the session time zone to the local time zone
+# If unset, uses the server's time zone, which is the Postgres default
+use_local_timezone = True
+
 # Custom colors for the completion menu, toolbar, etc.
 [colors]
 completion-menu.completion.current = 'bg:#ffffff #000000'

pgcli/pgexecute.py

@@ -881,3 +881,16 @@ def casing(self):
 
     def explain_prefix(self):
         return "EXPLAIN (ANALYZE, COSTS, VERBOSE, BUFFERS, FORMAT JSON) "
+
+    def get_timezone(self) -> str:
+        query = psycopg.sql.SQL("show time zone")
+        with self.conn.cursor() as cur:
+            cur.execute(query)
+            return cur.fetchone()[0]
+
+    def set_timezone(self, timezone: str):
+        query = psycopg.sql.SQL("set time zone {}").format(
+            psycopg.sql.Identifier(timezone)
+        )
+        with self.conn.cursor() as cur:
+            cur.execute(query)

pyproject.toml

@@ -40,6 +40,7 @@ dependencies = [
     # task manager. Also setproctitle is a hard dependency to install in Windows,
     # so we'll only install it if we're not in Windows.
     "setproctitle >= 1.1.9; sys_platform != 'win32' and 'CYGWIN' not in sys_platform",
+    "tzlocal >= 5.2",
 ]
 dynamic = ["version"]