Refactor IMDS credentials provider (#3267)

Author: jterapin

gems/aws-sdk-core/CHANGELOG.md

@@ -1,6 +1,10 @@
 Unreleased Changes
 ------------------
 
+* Issue - Skip `Aws::InstanceProfileCredentials` instantiation when `ENV['AWS_EC2_METADATA_DISABLED']` is set to `true` in the credential resolution chain.
+
+* Issue - Refactor `InstanceProfileCredentials` to improve code clarity and documentation. 
+
 3.226.2 (2025-07-01)
 ------------------
 

gems/aws-sdk-core/lib/aws-sdk-core/credential_provider_chain.rb

@@ -191,7 +191,7 @@ def instance_profile_credentials(options)
       if ENV['AWS_CONTAINER_CREDENTIALS_RELATIVE_URI'] ||
          ENV['AWS_CONTAINER_CREDENTIALS_FULL_URI']
         ECSCredentials.new(options)
-      else
+      elsif !(ENV.fetch('AWS_EC2_METADATA_DISABLED', 'false').downcase == 'true')
         InstanceProfileCredentials.new(options.merge(profile: profile_name))
       end
     end