Add AWS_SHARED_CREDENTIALS_FILE to get aws config

[kaiyan-sheng]

shared_credential_file can be set for the path to the shared credentials file. If empty/not set, it will be default to current user's home directory. For Linux/OSX is $HOME/.aws/credentials and for Windows is %USERPROFILE%\.aws\credentials.

closes #14157

How to test this:

Copy your aws credential to some other directory or change the name. I change mine to credentials-backup instead.

case1

Enable aws module in Metricbeat and change aws.yml to:

- module: aws
  period: 300s
  metricsets:
    - ec2
  regions:
    - us-east-1
  credential_profile_name: test-mb
  shared_credential_file: /Users/kaiyansheng/.aws/credentials-backup

You should see EC2 metrics flowing into ES with no credential error.

case2

Either with specified credential_profile_name but no shared_credential_file or specified shared_credential_file but no credential_profile_name should work.

Set valid credentials under [test-mb] profile in default credential file ~/.aws/credentials and test with config below:

- module: aws
  period: 300s
  metricsets:
    - ec2
  regions:
    - us-east-1
  credential_profile_name: test-mb

case3

Set valid credentials under [default] profile in credential file ~/.aws/credentials-backup and test with config below:

- module: aws
  period: 300s
  metricsets:
    - ec2
  regions:
    - us-east-1
  shared_credential_file: /Users/kaiyansheng/.aws/credentials-backup

case4

Set valid credentials under [default] profile in default credential file ~/.aws/credentials and test with config below without credential_profile_name or shared_credential_file:

- module: aws
  period: 300s
  metricsets:
    - ec2
  regions:
    - us-east-1

[jsoriano]

Thanks for looking at this, this will be very helpful in some scenarios!

[jsoriano]

Thanks for adding this feature! There is a small extra suggestion, but it LGTM.