MissingRegionError when using assume_role_credentials about fluent-plugin-s3

[repeatedly]

Hmm... could you send a PR?
I'm not sure where is the code did you edit.

Hi, for testing I added line 231 you see below. I hard-coded the value just for testing purposes. How do I send a PR?

227       when @assume_role_credentials
228         c = @assume_role_credentials
229         credentials_options[:role_arn] = c.role_arn
230         credentials_options[:role_session_name] = c.role_session_name
231         **credentials_options[:region] = 'us-east-1'**
232         credentials_options[:policy] = c.policy if c.policy
233         credentials_options[:duration_seconds] = c.duration_seconds if c.duration_seconds
234         credentials_options[:external_id] = c.external_id if c.external_id
235         options[:credentials] = Aws::AssumeRoleCredentials.new(credentials_options)

That was without the asterisks, sorry I was trying to make it bold. For clarity, the code is, with line 231 being the addition with a hard-coded value for testing/debugging.

227       when @assume_role_credentials
228         c = @assume_role_credentials
229         credentials_options[:role_arn] = c.role_arn
230         credentials_options[:role_session_name] = c.role_session_name
231         credentials_options[:region] = 'us-east-1'
232         credentials_options[:policy] = c.policy if c.policy
233         credentials_options[:duration_seconds] = c.duration_seconds if c.duration_seconds
234         credentials_options[:external_id] = c.external_id if c.external_id
235         options[:credentials] = Aws::AssumeRoleCredentials.new(credentials_options)

[repeatedly]

We have s3_region parameter so you cau use it.
See this code >

fluent-plugin-s3/lib/fluent/plugin/out_s3.rb

Line 107 in d6b7097

options[:region] = @s3_region if @s3_region

So sorry, the code above obviously was wrong. So when I did set the env variable AWS_REGION='us-east-1' the problem goes away. I did have the s3_region setup in the config file, but looks like it totally ignored it when using assume role.

This crazy code change did indeed work when the environment variable was not setup.
options[:credentials] = Aws::AssumeRoleCredentials.new(client: Aws::STS::Client.new(region: 'us-east-1'), role_arn: c.role_arn, role_session_name: c.role_session_name)

Of course, would be better if the S3 plugin could use the s3_region parameter in assume role.

[okkez]

Aws::AssumeRoleCredentials uses Aws::STS::Client without region by default.
We should set region to Aws::STS::Client.

See https://github.com/aws/aws-sdk-ruby/blob/master/aws-sdk-core/lib/aws-sdk-core/assume_role_credentials.rb#L39