Added module for utility functions. refs #9910

common/utils.py

@@ -0,0 +1,114 @@
+from six.moves import configparser
+import logging
+import os
+import requests
+
+
+def get_setting(config_file, config_name, setting, default=None):
+    """
+    Get setting value
+
+    :param str config_file: Configuration file path
+    :param str config_name: Name of configuration
+    :param str setting: Name of configuration setting to look up
+    :param str default: Default value if no configuration setting exists
+    :returns: str Configuration value
+    """
+    config = configparser.SafeConfigParser()
+    try:
+        config.read(config_file)
+        return config.get(config_name, setting)
+    except Exception:
+        return default
+
+
+def configure_logging(name, filename):
+    """
+    Configure logging
+
+    :param str name: Name of logger
+    :param str filename: Filename of log
+    :returns: None
+    """
+    CONFIG = {
+        'version': 1,
+        'disable_existing_loggers': False,
+        'formatters': {
+            'default': {
+                'format': '%(levelname)-8s  %(asctime)s  %(filename)s:%(lineno)-4s %(message)s',
+                'datefmt': '%Y-%m-%d %H:%M:%S',
+            },
+        },
+        'handlers': {
+            'console': {
+                'class': 'logging.StreamHandler',
+                'formatter': 'default',
+            },
+            'file': {
+                'class': 'logging.handlers.RotatingFileHandler',
+                'formatter': 'default',
+                'filename': filename,
+                'backupCount': 2,
+                'maxBytes': 10 * 1024,
+            },
+        },
+        'loggers': {
+            name: {
+                'level': 'INFO',  # One of INFO, DEBUG, WARNING, ERROR, CRITICAL
+                'handlers': ['console', 'file'],
+            },
+        },
+    }
+    logging.config.dictConfig(CONFIG)
+
+
+def open_pid_file(pid_file, logger=None):
+    """
+    Open pidfile
+
+    :param str pid_file: Desired path for pidfile
+    :param Logger logger: Logger to log opening issues to
+    :returns: True if a pidfile could be opened or None
+    """
+    try:
+        # Open PID file only if it doesn't exist for read/write
+        f = os.fdopen(os.open(pid_file, os.O_CREAT | os.O_EXCL | os.O_RDWR), 'r+')
+    except OSError as e:
+         if logger:
+             logger.info('Error accessing pid file %s: %s', pid_file, exc_info=True)
+         return None
+    except Exception:
+        if logger:
+            logger.info('This script is already running. To override this behaviour and start a new run, remove %s', pid_file)
+        return None
+    else:
+        pid = os.getpid()
+        f.write(str(pid))
+        f.close()
+    return True
+
+
+def call_url_json(url, params, logger=None):
+    """
+    Helper to GET a URL where the expected response is 200 with JSON.
+
+    :param str url: URL to call
+    :param dict params: Params to pass to requests.get
+    :returns: Dict of the returned JSON or None
+    """
+    if logger:
+        logger.debug('URL: %s; params: %s;', url, params)
+    response = requests.get(url, params=params)
+    if logger:
+        logger.debug('Response: %s', response)
+    if not response.ok:
+        if logger:
+            logger.warning('Request to %s returned %s %s', url, response.status_code, response.reason)
+            logger.debug('Response: %s', response.text)
+        return None
+    try:
+        return response.json()
+    except ValueError:  # JSON could not be decoded
+        if logger:
+            logger.warning('Could not parse JSON from response: %s', response.text)
+        return None