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)
 
 Creator:
 --------

changelog.rst

@@ -5,6 +5,7 @@ Features
 --------
 * Add a `--ping` command line option; allows pgcli to replace `pg_isready`
 * Changed the packaging metadata from setup.py to pyproject.toml
+* The session time zone setting is set to the system time zone by default
 
 Bug fixes:
 ----------

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
@@ -1624,6 +1626,30 @@ def cli(
     else:
         pgcli.connect(database, host, user, port)
 
+    local_tz = None
+    try:
+        local_tz = tzlocal.get_localzone_name()
+
+        if local_tz is None:
+            click.secho(
+                "No local time zone configuration found",
+                err=True,
+                fg="yellow",
+            )
+    except ZoneInfoNotFoundError as e:
+        # e.args[0] is the pre-formatted message which includes a list
+        # of conflicting sources
+        click.secho(e.args[0], err=True, fg="yellow")
+
+    if local_tz is not None:
+        pgcli.pgexecute.set_timezone(local_tz)
+    else:
+        click.secho(
+            "Continuing with the default server time zone",
+            err=True,
+            fg="yellow",
+        )
+
     if list_databases:
         cur, headers, status = pgcli.pgexecute.full_databases()
 

pgcli/pgexecute.py

@@ -881,3 +881,10 @@ def casing(self):
 
     def explain_prefix(self):
         return "EXPLAIN (ANALYZE, COSTS, VERBOSE, BUFFERS, FORMAT JSON) "
+
+    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"]