utils.py 文件源码

def parse_config(config_path):
    """Checks if secrets need to be fetched from the environment"""

    temp_path = "%s.tmp" % config_path

    # Template yaml file
    with open(config_path, 'r') as stream:
        try:
            temp = template_yaml(yaml.load(stream))
        except yaml.YAMLError as exc:
            raise ValueError("Invalid config passed to the program: %s" % exc)

    # Dump templated file back to file-system
    with open(temp_path, 'w') as outfile:
        yaml.safe_dump(temp, outfile, default_flow_style=False)

    # Add environment resolver
    pattern_env = re.compile(r'^(.*)\<%= ENV\[\'(.*)\'\] %\>(.*)$')
    yaml.add_implicit_resolver("!pathex", pattern_env)

    # Add command resolver
    pattern_cmd = re.compile(r'^(.*)\<%= CMD\[\'(.*)\'\] %\>(.*)$')
    yaml.add_implicit_resolver("!pathcmd", pattern_cmd)

    # Add function resolver
    pattern_fun = re.compile(r'^(.*)\<%= FUNC\[\'(.*)\((.*)\)\'\] %\>(.*)$')
    yaml.add_implicit_resolver("!func", pattern_fun)

    def pathex_constructor(loader, node):
        """Processes environment variables found in the YAML"""
        value = loader.construct_scalar(node)
        before_path, env_var, remaining_path = pattern_env.match(value).groups()
        return before_path + os.environ[env_var] + remaining_path

    def pathcmd_constructor(loader, node):
        """Processes command variables found in the YAML"""
        value = loader.construct_scalar(node)
        before_path, cmd_var, remaining_path = pattern_cmd.match(value).groups()
        retval = output_value(execute(cmd_var, None, True, True), True)
        return before_path + retval.decode("utf-8") + remaining_path

    def fun_constructor(loader, node):
        """Processes embedded functions found in the YAML"""
        value = loader.construct_scalar(node)
        before_path, fun, arg, remaining_path = pattern_fun.match(value).groups()
        retval = PREDEFINED_FUNCTIONS[fun](arg)
        return before_path + retval.decode("utf-8") + remaining_path

    yaml.add_constructor("!pathex", pathex_constructor)
    yaml.add_constructor("!pathcmd", pathcmd_constructor)
    yaml.add_constructor("!func", fun_constructor)

    with open(temp_path, 'r') as stream:
        try:
            return yaml.load(stream)
        except yaml.YAMLError as exc:
            raise ValueError("Invalid config passed to the program: %s" % exc)