CODEWITHSUNDEEP
amazon-web-servicesamazon-ec2
Ethan Barron
Ethan Barron

Reputation: 1304

Interaction with the AWS API?

I've gotten the necessary access key/signature from my client and I can interact with the API through the Ruby SDK right now. Thing is, the Ruby SDK doesn't have any kind of high-level API methods to request a spot instance. So, I need to do this manually via raw REST API requests.

Basically, the authentication information that I am using is correct (as it works via the Ruby SDK), but I can't get raw requests to work... I either get back the spot request wizard webpage as the response, or an error: The request signature we calculated does not match the signature you provided. Check your AWS Secret Access Key and signing method. Consult the service documentation for details.

Here's the URL I'm using: 

https://ec2.amazonaws.com/?Action=RequestSpotInstances
&SpotPrice.1=0.05
&AvailabilityZoneGroup.1=us-east-1c
&LaunchSpecification.ImageId.1=THE_AMI_ID
&LaunchSpecification.KeyName.1=THE_KEYPAIR
&LaunchSpecification.InstanceType.1=m1.medium
&AWSAccessKeyId=THE_ACCESS_KEY
&Signature=THE_ACCESS_SIGNATURE
&Version=>2013-10-01
&Expires=>THE_EXPIRATION_TIME_36000_SECONDS_LATER_THAN_NOW
&SignatureVersion=2
&SignatureMethod=HmacSHA256

Any ideas on why this won't work? I've tried exploring the Ruby SDK code to see how they are doing it, but it's so complex, I can't figure out where this action actually takes place. Thanks!

Upvotes: 0

Views: 380

Answers (1)

Vadym Fedorov
Vadym Fedorov

Reputation: 2415

How do you calculate signature? First at all check that you use correct signing process version. AWS api actually supports versions v2 and v4. Some aws resources supports both versions, some just v2 or v4. Base on this I would recommend to do following:

  1. Check what version of the signing did you implement. More on versions: http://docs.aws.amazon.com/general/latest/gr/signing_aws_api_requests.html

  2. Check is your implementation match with algorithm described here: http://docs.aws.amazon.com/general/latest/gr/signature-version-2.html

Upvotes: 2

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