Source code for libcloud.common.exceptions

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import time

from email.utils import parsedate_tz, mktime_tz

__all__ = ["BaseHTTPError", "RateLimitReachedError", "exception_from_message"]

[docs]class BaseHTTPError(Exception): """ The base exception class for all HTTP related exceptions. """ def __init__(self, code, message, headers=None): self.code = code self.message = message self.headers = headers # preserve old exception behavior for tests that # look for e.args[0] super(BaseHTTPError, self).__init__(message) def __str__(self): return self.message
[docs]class RateLimitReachedError(BaseHTTPError): """ HTTP 429 - Rate limit: you've sent too many requests for this time period. """ code = 429 message = "%s Rate limit exceeded" % (code) def __init__(self, *args, **kwargs): headers = kwargs.pop("headers", None) super(RateLimitReachedError, self).__init__(self.code, self.message, headers) if self.headers is not None: self.retry_after = float(self.headers.get("retry-after", 0)) else: self.retry_after = 0
_error_classes = [RateLimitReachedError] _code_map = dict((c.code, c) for c in _error_classes)
[docs]def exception_from_message(code, message, headers=None): """ Return an instance of BaseHTTPException or subclass based on response code. If headers include Retry-After, RFC 2616 says that its value may be one of two formats: HTTP-date or delta-seconds, for example: Retry-After: Fri, 31 Dec 1999 23:59:59 GMT Retry-After: 120 If Retry-After comes in HTTP-date, it'll be translated to a positive delta-seconds value when passing it to the exception constructor. Also, RFC 2616 says that Retry-After isn't just only applicable to 429 HTTP status, but also to other responses, like 503 and 3xx. Usage:: raise exception_from_message(code=self.status, message=self.parse_error(), headers=self.headers) """ kwargs = {"code": code, "message": message, "headers": headers} if headers and "retry-after" in headers: http_date = parsedate_tz(headers["retry-after"]) if http_date is not None: # Convert HTTP-date to delay-seconds delay = max(0, int(mktime_tz(http_date) - time.time())) headers["retry-after"] = str(delay) cls = _code_map.get(code, BaseHTTPError) return cls(**kwargs)