zulip/scripts/lib/sharding.py

103 lines
3.8 KiB
Python
Executable File

#!/usr/bin/env python3
import argparse
import filecmp
import json
import os
import subprocess
import sys
from typing import Any, Dict
BASE_DIR = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
sys.path.append(BASE_DIR)
from scripts.lib.setup_path import setup_path
setup_path()
from scripts.lib.zulip_tools import get_config_file, get_tornado_ports
def write_realm_nginx_config_line(f: Any, host: str, port: str) -> None:
f.write(f"""if ($host = '{host}') {{
set $tornado_server http://tornado{port};
}}\n""")
# Basic system to do Tornado sharding. Writes two output .tmp files that need
# to be renamed to the following files to finalize the changes:
# * /etc/zulip/nginx_sharding.conf; nginx needs to be reloaded after changing.
# * /etc/zulip/sharding.json; supervisor Django process needs to be reloaded
# after changing. TODO: We can probably make this live-reload by statting the file.
#
# TODO: Restructure this to automatically generate a sharding layout.
def write_updated_configs() -> None:
config_file = get_config_file()
ports = get_tornado_ports(config_file)
expected_ports = list(range(9800, max(ports)+1))
assert sorted(ports) == expected_ports, \
f"ports ({sorted(ports)}) must be contiguous, starting with 9800"
with open('/etc/zulip/nginx_sharding.conf.tmp', 'w') as nginx_sharding_conf_f, \
open('/etc/zulip/sharding.json.tmp', 'w') as sharding_json_f:
if len(ports) == 1:
nginx_sharding_conf_f.write("set $tornado_server http://tornado;\n")
sharding_json_f.write('{}\n')
return
nginx_sharding_conf_f.write("set $tornado_server http://tornado9800;\n")
shard_map: Dict[str, int] = {}
external_host = subprocess.check_output([os.path.join(BASE_DIR, 'scripts/get-django-setting'),
'EXTERNAL_HOST'],
universal_newlines=True).strip()
for port in config_file["tornado_sharding"]:
shards = config_file["tornado_sharding"][port].strip()
if shards:
for shard in shards.split(' '):
if '.' in shard:
host = shard
else:
host = f"{shard}.{external_host}"
assert host not in shard_map, f"host {host} duplicated"
shard_map[host] = int(port)
write_realm_nginx_config_line(nginx_sharding_conf_f, host, port)
nginx_sharding_conf_f.write('\n')
sharding_json_f.write(json.dumps(shard_map) + '\n')
parser = argparse.ArgumentParser(
description="Adjust Tornado sharding configuration",
)
parser.add_argument(
"--errors-ok", action="store_true",
help="Exits 1 if there are no changes; if there are errors or changes, exits 0."
)
options = parser.parse_args()
config_file_path = "/etc/zulip"
base_files = ['nginx_sharding.conf', 'sharding.json']
full_real_paths = [f"{config_file_path}/{filename}" for filename in base_files]
full_new_paths = [f"{filename}.tmp" for filename in full_real_paths]
try:
write_updated_configs()
for old, new in zip(full_real_paths, full_new_paths):
if not filecmp.cmp(old, new):
# There are changes; leave .tmp files and exit 0
if "SUPPRESS_SHARDING_NOTICE" not in os.environ:
print("===> Updated sharding; run scripts/refresh-sharding-and-restart")
sys.exit(0)
# No changes; clean up and exit 1
for filename in full_new_paths:
os.unlink(filename)
sys.exit(1)
except AssertionError as e:
# Clean up whichever files we made
for filename in full_new_paths:
if os.path.exists(filename):
os.unlink(filename)
if options.errors_ok:
sys.exit(0)
else:
print(e, file=sys.stderr)
sys.exit(2)