[REF] runbot: proof of concept standalone script

Actually, when deploying multiple instances of runbot, a full odoo
installation is needed.

With this commit, a single standalone (sort of) can be used to start a
runbot builder. It uses the same database as the runbot scheduler.
This script just reserve pending builds for himself and starts to build.

This is just a proof of concept. It should work alongside with a
standard runbot installation.

runbot_builder/builder.py

@@ -0,0 +1,106 @@
+#!/usr/bin/python3
+import argparse
+import logging
+import os
+import socket
+import sys
+import time
+import threading
+import signal
+
+LOG_FORMAT = '%(asctime)s %(levelname)s %(name)s: %(message)s'
+logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
+logging.getLogger('odoo.addons.runbot').setLevel(logging.DEBUG)
+logging.addLevelName(25, "!NFO")
+
+_logger = logging.getLogger(__name__)
+
+
+class RunbotClient():
+
+    def __init__(self, env, args):
+        self.env = env
+        self.args = args
+        self.fqdn = socket.getfqdn()
+        self.ask_interrupt = threading.Event()
+
+    def main_loop(self):
+        from odoo import fields
+        signal.signal(signal.SIGINT, self.signal_handler)
+        signal.signal(signal.SIGTERM, self.signal_handler)
+        host = self.env['runbot.host']._get_current()
+        count = 0
+        while True:
+            count = count % 60
+            if count == 0:
+                logging.info('Host %s running with %s slots on pid %s%s', host.name, host.get_nb_worker(), os.getpid(), ' (assigned only)' if host.assigned_only else '')
+                self.env['runbot.repo']._source_cleanup()
+                self.env['runbot.build']._local_cleanup()
+                host.last_end_loop = host.last_start_loop = fields.Datetime.now()
+                host.set_psql_conn_count()
+            count += 1
+            sleep_time = self.env['runbot.repo']._scheduler_loop_turn(host)
+            self.env.cr.commit()
+            self.env.reset()
+            self.sleep(sleep_time)
+            if self.ask_interrupt.is_set():
+                return
+
+    def signal_handler(self, signal, frame):
+        if self.ask_interrupt.is_set():
+            _logger.info("Second Interrupt detected, force exit")
+            os._exit(1)
+
+        _logger.info("Interrupt detected")
+        self.ask_interrupt.set()
+
+    def sleep(self, t):
+        self.ask_interrupt.wait(t)
+
+
+def run():
+    # parse args
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--odoo-path', help='Odoo sources path')
+    parser.add_argument('--db_host', default='127.0.0.1')
+    parser.add_argument('--db_port', default='5432')
+    parser.add_argument('--db_user')
+    parser.add_argument('--db_password')
+    parser.add_argument('-d', '--database', default='runbot', help='name of runbot db')
+    parser.add_argument('--logfile', default=False)
+    args = parser.parse_args()
+    if args.logfile:
+        dirname = os.path.dirname(args.logfile)
+        if dirname and not os.path.isdir(dirname):
+            os.makedirs(dirname)
+
+        handler = logging.FileHandler(args.logfile)
+        formatter = logging.Formatter(LOG_FORMAT)
+        handler.setFormatter(formatter)
+        logging.getLogger().addHandler(handler)
+
+    _logger.info("Staring sheduler on database %s", args.database)
+
+    # configure odoo
+    sys.path.append(args.odoo_path)
+    import odoo
+    odoo.tools.config['db_host'] = args.db_host
+    odoo.tools.config['db_port'] = args.db_port
+    odoo.tools.config['db_user'] = args.db_user
+    odoo.tools.config['db_password'] = args.db_password
+    addon_path = os.path.abspath(os.path.join(os.path.dirname(os.path.realpath(__file__)), '..'))
+    config_addons_path = odoo.tools.config['addons_path']
+    odoo.tools.config['addons_path'] = ','.join([config_addons_path, addon_path])
+
+    # create environment
+    registry = odoo.registry(args.database)
+    with odoo.api.Environment.manage():
+        with registry.cursor() as cr:
+            env = odoo.api.Environment(cr, odoo.SUPERUSER_ID, {})
+            runbot_client = RunbotClient(env, args)
+            # run main loop
+            runbot_client.main_loop()
+
+if __name__ == '__main__':
+    run()
+    _logger.info("Stopping gracefully")