scripts: Add a script to stop the server.

Using `supervisorctl stop all` to stop the server is not terribly
discoverable, and may stop services which are not part of Zulip
proper.

Add an explicit tool which only stops the relevant services.  It also
more carefully controls the order in which services are stopped to
minimize lost requests, and maximally quiesce the server.

Locations which may be stopping _older_ versions of Zulip (without
this script) are left with using `supervisorctl stop all`.

Fixes #14959.

docs/production/export-and-import.md

@@ -257,7 +257,7 @@ For best results, you'll want to shut down access to the organization
 before exporting; so that nobody can send new messages (etc.)  while
 you're exporting data.  There are two ways to do this:
 
-1. `supervisorctl stop all`, which stops the whole server.  This is
+1. `./scripts/stop-server`, which stops the whole server.  This is
 preferred if you're not hosting multiple organizations, because it has
 no side effects other than disabling the Zulip server for the
 duration.
@@ -282,7 +282,7 @@ following commands:
 
 ```
 cd /home/zulip/deployments/current
-# supervisorctl stop all                  # Stops the Zulip server
+# ./scripts/stop-server
 # export DEACTIVATE_FLAG="--deactivate"   # Deactivates the organization
 ./manage.py export -r '' $DEACTIVATE_FLAG # Exports the data
 ```
@@ -316,7 +316,7 @@ archive of all the organization's uploaded files.
       several months of development ahead of the latest release.
 
     * Note that if your server has limited free RAM, you'll want to
-      shut down the Zulip server with `supervisorctl stop all` while
+      shut down the Zulip server with `./scripts/stop-server` while
       you run the import, since our minimal system requirements do not
       budget extra RAM for running the data import tool.
 

docs/production/troubleshooting.md

@@ -87,6 +87,9 @@ Similarly, you can stop Zulip using:
 supervisorctl stop all
 ```
 
+If you're looking to shut down the server, it is often better to run
+`./scripts/stop-server`.
+
 ## Troubleshooting services
 
 The Zulip application uses several major open source services to store

docs/production/upgrade-or-modify.md

@@ -415,7 +415,6 @@ To upgrade the version of PostgreSQL on the Zulip server:
 2. Stop the server and take a backup:
 
     ```
-    sudo -i # Or otherwise get a root shell
     supervisorctl stop all
     /home/zulip/deployments/current/manage.py backup --output=/home/zulip/postgresql-upgrade.backup.tar.gz
     ```

scripts/setup/postgresql-init-db

@@ -28,7 +28,7 @@ fi
 
 # Shut down all services to ensure a quiescent state.
 if [ -e "/var/run/supervisor.sock" ]; then
-    supervisorctl stop all
+    su zulip -c "$(dirname "$(dirname "$0")")/stop-server"
 fi
 
 # Drop any open connections to any old database.

scripts/stop-server

@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+import logging
+import os
+import pwd
+import subprocess
+import sys
+import time
+
+sys.path.append(os.path.join(os.path.dirname(__file__), ".."))
+from scripts.lib.zulip_tools import ENDC, OKGREEN, WARNING
+
+deploy_path = os.path.realpath(os.path.join(os.path.dirname(__file__), ".."))
+os.chdir(deploy_path)
+
+if pwd.getpwuid(os.getuid()).pw_name != "zulip":
+    logging.error("Must be run as user 'zulip'.")
+    sys.exit(1)
+
+logging.Formatter.converter = time.gmtime
+logging.basicConfig(format="%(asctime)s stop-server: %(message)s", level=logging.INFO)
+
+services = []
+
+# Start with the least-critical services:
+if os.path.exists("/etc/supervisor/conf.d/zulip/zulip_db.conf"):
+    services.append("process-fts-updates")
+
+if os.path.exists("/etc/supervisor/conf.d/zulip/thumbor.conf"):
+    services.append("zulip-thumbor")
+
+# Contrary to the order in (re)start-server, we stop django before the
+# workers, to increase the chance that we finish processing any work
+# that may have been enqueued by the Django, leaving the final state
+# closer to "empty."  We stop Django before Tornado so it doesn't try
+# to make requests to make queues with a down'd Tornado.
+services.append("zulip-django")
+services.extend(["zulip-tornado", "zulip-tornado:*"])
+services.append("zulip-workers:*")
+
+subprocess.check_call(["supervisorctl", "stop", *services])
+
+print()
+print(OKGREEN + "Zulip stopped successfully!" + ENDC)
+
+using_sso = subprocess.check_output(["./scripts/get-django-setting", "USING_APACHE_SSO"])
+if using_sso.strip() == b"True":
+    print()
+    print(WARNING + "Apache2 needs to be shut down; as root, run:" + ENDC)
+    print("    service apache2 stop")
+    print()

templates/zerver/help/import-from-gitter.md

@@ -49,7 +49,7 @@ the most common configuration, run the following commands:
 
 ```
 cd /home/zulip/deployments/current
-supervisorctl stop all  # Stop the Zulip server
+./scripts/stop-server
 ./manage.py convert_gitter_data gitter_data.json --output converted_gitter_data
 ./manage.py import '' converted_gitter_data
 ./scripts/restart-server

templates/zerver/help/import-from-mattermost.md

@@ -149,7 +149,7 @@ the most common configuration, run the following commands, replacing
 cd /home/zulip
 tar -xzvf export.tar.gz
 cd /home/zulip/deployments/current
-supervisorctl stop all  # Stop the Zulip server
+./scripts/stop-server
 ./manage.py convert_mattermost_data /home/zulip/mattermost --output /home/zulip/converted_mattermost_data
 ./manage.py import "" /home/zulip/converted_mattermost_data/<team-name>
 ./scripts/restart-server

templates/zerver/help/import-from-slack.md

@@ -79,7 +79,7 @@ the most common configuration, run the following commands, replacing
 
 ```
 cd /home/zulip/deployments/current
-supervisorctl stop all  # Stop the Zulip server
+./scripts/stop-server
 ./manage.py convert_slack_data slack_data.zip --token <token> --output converted_slack_data
 ./manage.py import '' converted_slack_data
 ./scripts/restart-server

tools/ci/production-upgrade-pg

@@ -3,10 +3,10 @@
 set -e
 set -x
 
-ZULIP_PATH=/home/github/zulip
+cd /home/github/zulip
 
-supervisorctl stop all
-"$ZULIP_PATH"/scripts/setup/upgrade-postgresql
+su zulip -c ./scripts/stop-server
+./scripts/setup/upgrade-postgresql
 supervisorctl start all
 
 echo "Upgrade of PostgreSQL complete!"