Source code for src.driver.driver

.. module:: driver
   :synopsis: Main entry point for ep2


from configparser import SafeConfigParser
import time
import optparse
import os
from .defaultparams import default_params
from .bootstrap import bootstrap
import logging

CONFIG_FILE = "/etc/ep2/ep2.conf"
LOCK_FILE = default_params.get("lock_dir")

[docs]def drive(): """ **Method for starting ep2** This is the entry method which starts ep2 controller. It calls bootstrap module for bootstrapping ep2, reads ep2 config, initialises haproxy and starts the **poll-update-repeat loop** Returns: None: Returns nothing """ global CONFIG_FILE global LOCK_FILE # parse args parser = optparse.OptionParser() parser.add_option('-f', action="store", dest="config", help="Config file") options, args = parser.parse_args() # if config file available as argument, then use it if options.config: CONFIG_FILE = options.config # parse the config and create a dictionary config = __load_config() haproxy_config = config.get("haproxy") # load values/defaults SLEEP_BEFORE_NEXT_RUN = int(haproxy_config.get("sleep_before_next_run")) SLEEP_BEFORE_NEXT_LOCK_ATTEMPT = int(haproxy_config.get("sleep_before_next_lock_attempt")) LOG_FILE = haproxy_config.get("log_file") logger = __setup_logging(LOG_FILE) if not __sanitize_config(config): # if configs fail sanity checks then exit ep2. Issue should have been logged already exit(2) # bootstrap the controller running, haproxyupdater, orchestratorHandler, driverCache = bootstrap(config=config, logger=logger) if not running: ''' Error has already been logged. Exit with status code 2 ''' exit(2) ''' After this point, Haproxy should be running with the lastest IPs fetched from the orchestrator. Now we can begin with the poll-update-repeat loop for updating backends fetched from ochestrator ''' while True: # Fetch backend IPs from orchestrator handler asg_ips = orchestratorHandler.fetch() # Proceed with updation only if IPs are not none if asg_ips != None: # check if update is actually neccessary. Compare with cache should_update = driverCache.need_to_update(set(asg_ips)) if should_update:"Backends changed. Proceeding to update haproxy") # Inform the haproxyupdater about the new nodes haproxyupdater.update_node_list(asg_ips) # Update haproxy updated = haproxyupdater.update_haproxy() else:"Backends not changed. Skipping update") else: logger.critical("No backends found. Skippin run") # sleep for configured time before the next run time.sleep(SLEEP_BEFORE_NEXT_RUN)
def __setup_logging(log_file): """ **Method for setting up logging** Here the logging for EP2 controller is setup with desired format and path. Args: log_file (str) : Path to log file Returns: logger: logger object for logging logs """ logger = logging.getLogger(__name__) logger.setLevel(logging.DEBUG) logger_handler = logging.FileHandler(log_file) logger_handler.setLevel(logging.DEBUG) logger_formatter = logging.Formatter(fmt='%(asctime)s %(levelname)-8s %(message)s', datefmt='%Y-%m-%d %H:%M:%S') logger_handler.setFormatter(logger_formatter) logger.addHandler(logger_handler) return logger def __load_config(): """ **Method for loading config** Configfile is read and parsed. The keys and values are converted into dictionary format. There are separate sections for haproxy and orechestrator. Accordingly the dictionary is made. Returns: dictionary: A dictionary containing config options """ parser = SafeConfigParser() config = {} for section in parser.sections(): config[section.lower()] = {} for name, value in parser.items(section): config[section.lower()][name] = value config = merge_with_default_config(config) return config
[docs]def merge_with_default_config(config): haproxy_config = config.get("haproxy") for key in default_params: if not haproxy_config.get(key): haproxy_config[key] = default_params[key] config["haproxy"] = haproxy_config return config
def __can_aquire_lock(lock_dir): if not os.path.exists(lock_dir): return True def __aquire_lock(lock_dir): lock_file = os.path.join(lock_dir, LOCK_FILE) try: if not os.path.exists(lock_file): with open(lock_file, "w") as lock_file: lock_file.write(str(os.getpid())) return True return False except Exception as ex: print (ex) return False def __release_lock(lock_dir): lock_file = os.path.join(lock_dir, LOCK_FILE) try: if os.path.exists(lock_file): os.unlink(lock_file) return True except Exception as ex: print (ex) return False def __sanitize_config(config): """ **Method for checking config sanity** Returns: bool: Returns whether sanity checks are success or failure """ return True if __name__ == "__main__": drive()