Amazon Web Services version 4 authentication for the Python Requests library.
- Requests authentication for all AWS services that support AWS auth v4
- Independent signing key objects
- Automatic regeneration of keys when scope date boundary is passed
- Support for STS temporary credentials
Implements header-based authentication, GET URL parameter and POST parameter authentication are not supported.
This package has been tested as working against:
AppStream, Auto-Scaling, CloudFormation, CloudFront, CloudHSM, CloudSearch, CloudTrail, CloudWatch Monitoring, CloudWatch Logs, CodeDeploy, Cognito Identity, Cognito Sync, Config, DataPipeline, Direct Connect, DynamoDB, Elastic Beanstalk, ElastiCache, EC2, EC2 Container Service, Elastic Load Balancing, Elastic MapReduce, ElasticSearch, Elastic Transcoder, Glacier, Identity and Access Management (IAM), Key Management Service (KMS), Kinesis, Lambda, Opsworks, Redshift, Relational Database Service (RDS), Route 53, Simple Storage Service (S3), Simple Notification Service (SNS), Simple Queue Service (SQS), Storage Gateway, Security Token Service (STS)
The following services do not support AWS auth version 4 and are not usable with this package:
Simple Email Service (SES), Simple Workflow Service (SWF), Import/Export, SimpleDB, DevPay, Mechanical Turk
The AWS Support API has not been tested as it requires a premium subscription.
Install via pip:
$ pip install requests-aws4authrequests-aws4auth requires the Requests library by Kenneth Reitz.
requests-aws4auth is tested on Python 2.7 and 3.3 and up.
Version 0.8 introduces request date checking and automatic key regeneration behaviour as default. This has implications for sharing authentication objects between threads, and for storage of secret keys. See the relevant sections below for details. See also the discussion in GitHub issue #10.
>>> import requests
>>> from requests_aws4auth import AWS4Auth
>>> endpoint = 'http://s3-eu-west-1.amazonaws.com'
>>> auth = AWS4Auth('<ACCESS ID>', '<ACCESS KEY>', 'eu-west-1', 's3')
>>> response = requests.get(endpoint, auth=auth)
>>> response.text
<?xml version="1.0" encoding="UTF-8"?>
<ListAllMyBucketsResult xmlns="http://s3.amazonaws.com/doc/2006-03-01">
<Owner>
<ID>bcaf1ffd86f461ca5fb16fd081034f</ID>
<DisplayName>webfile</DisplayName>
...This example would list your buckets in the eu-west-1 region of the Amazon
S3 service.
>>> from requests_aws4auth import AWS4Auth
>>> auth = AWS4Auth('<ACCESS ID>', '<ACCESS KEY>', 'eu-west-1', 's3',
session_token='<SESSION TOKEN>')
...This example shows how to construct an AWS4Auth object for use with STS
temporary credentials. The x-amz-security-token header is added with
the session token. Temporary credential timeouts are not managed -- in
case the temporary credentials expire, they need to be re-generated and
the AWS4Auth object re-constructed with the new credentials.
If an HTTP request to be authenticated contains a Date or X-Amz-Date
header, AWS will only accept the authorised request if the date in the header
matches the scope date of the signing key (see the AWS REST API date docs).
From version 0.8 of requests-aws4auth, if the header date does not match the
scope date, an AWS4Auth instance will automatically regenerate its signing
key, using the same scope parameters as the previous key except for the date,
which will be changed to match the request date. If a request does not include
a date, the current date is added to the request in an X-Amz-Date header,
and the signing key is regenerated if this differs from the scope date.
This means that AWS4Auth now extracts and parses dates from the values of
X-Amz-Date and Date headers. Supported date formats are:
- RFC 7231 (e.g. Mon, 09 Sep 2011 23:36:00 GMT)
- RFC 850 (e.g. Sunday, 06-Nov-94 08:49:37 GMT)
- C time (e.g. Wed Dec 4 00:00:00 2002)
- Amz-Date format (e.g. 20090325T010101Z)
- ISO 8601 / RFC 3339 (e.g. 2009-03-25T10:11:12.13-01:00)
If either header is present but AWS4Auth cannot extract a date because all
present date headers are in an unrecognisable format, AWS4Auth will delete
any X-Amz-Date and Date headers present and replace with a single
X-Amz-Date header containing the current date. This behaviour can be
modified using the raise_invalid_date keyword argument of the AWS4Auth
constructor.
If you do not want the signing key to be automatically regenerated when a
mismatch between the request date and the scope date is encountered, use the
alternative StrictAWS4Auth class, which is identical to AWS4Auth except
that upon encountering a date mismatch it just raises a DateMismatchError.
You can also use the PassiveAWS4Auth class, which mimics the AWS4Auth
behaviour prior to version 0.8 and just signs and sends the request, whether
the date matches or not. In this case it is up to the calling code to handle an
authentication failure response from AWS caused by the date mismatch.
To allow automatic key regeneration, the secret key is stored in the
AWS4Auth instance, in the signing key object. If you do not want this to
occur, instantiate the instance using an AWS4Signing key which was created
with the store_secret_key parameter set to False:
>>> sig_key = AWS4SigningKey(secret_key, region, service, date, False)
>>> auth = StrictAWS4Auth(access_id, sig_key)The AWS4Auth class will then raise a NoSecretKeyError when it attempts
to regenerate its key. A slightly more conceptually elegant way to handle this
is to use the alternative StrictAWS4Auth class, again instantiating it with
an AWS4SigningKey instance created with store_secret_key = False.
If you share AWS4Auth (or even StrictAWS4Auth) instances between
threads you are likely to encounter problems. Because AWS4Auth instances
may unpredictably regenerate their signing key as part of signing a request,
threads using the same instance may find the key changed by another thread
halfway through the signing process, which may result in undefined behaviour.
It may be possible to rig up a workable instance sharing mechanism using
locking primitives and the StrictAWS4Auth class, however this poor author
can't think of a scenario which works safely yet doesn't suffer from at some
point blocking all threads for at least the duration of an HTTP request, which
could be several seconds. If several requests come in in close succession which
all require key regenerations then the system could be forced into serial
operation for quite a length of time.
In short, it's probably best to create a thread-local instance of AWS4Auth
for each thread that needs to do authentication.
See the doctrings in aws4auth.py and aws4signingkey.py.
A test suite is included in the test folder.
The package passes all tests in the AWS auth v4 test_suite, and contains
tests against the supported live services. See docstrings in
test/requests_aws4auth_test.py for details about running the tests.
Connection parameters are included in the tests for the AWS Support API, should you have access and want to try it. The documentation says it supports auth v4 so it should work if you have a subscription. Do pass on your results!
- Currently does not support Amazon S3 chunked uploads
- Tests for new AWS services
- Requires Requests library to be present even if only using AWS4SigningKey
- Coherent documentation