Revert "Example of streamlining retries from Instance Profile Credentials"

This reverts commit e4153b3.

Author: jterapin

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

@@ -36,8 +36,7 @@ class InstanceProfileCredentials
     #   called with an instance of this object when AWS credentials are required and need to be refreshed.
     def initialize(options = {})
       @ec2_metadata = options.delete(:ec2_metadata) || build_ec2_metadata_client(options)
-      @retries = options.delete(:retries) || 3
-      @backoff = resolve_backoff(options[:backoff])
+
       @no_refresh_until = nil
       @async_refresh = false
       @metrics = ['CREDENTIALS_IMDS']
@@ -53,9 +52,7 @@ def build_ec2_metadata_client(options)
       opts = options.merge(
         endpoint_mode: resolve_endpoint_mode(options),
         endpoint: resolve_endpoint(options),
-        disable_imds_v1: resolve_disable_v1(options),
-        retries: 0,
-        backoff: 0
+        disable_imds_v1: resolve_disable_v1(options)
       )
       if (delay = opts.delete(:delay))
         warn('The `:delay` option is deprecated. Use `:backoff` instead.')
@@ -97,7 +94,15 @@ def refresh
         return
       end
 
-      new_creds = retry_errors { Aws::Json.load(fetch_credentials) }
+      new_creds =
+        begin
+          retry_json_errors { Aws::Json.load(fetch_credentials) }
+        rescue Aws::Json::ParseError
+          raise Aws::Errors::MetadataParserError
+        rescue StandardError => e
+          warn("Error retrieving instance profile credentials: #{e}")
+          '{}'
+        end
 
       if !empty_credentials?(@credentials) && (!new_creds['AccessKeyId'] || new_creds['AccessKeyId'].empty?)
         # credentials are already set, but there was an error getting new credentials
@@ -120,6 +125,9 @@ def fetch_credentials
       metadata = @ec2_metadata.get(METADATA_PATH_BASE)
       profile_name = metadata.lines.first.strip
       @ec2_metadata.get(METADATA_PATH_BASE + profile_name)
+    rescue StandardError => e
+      warn("Error retrieving instance profile credentials: #{e}")
+      '{}'
     end
 
     def update_credentials(creds)
@@ -140,42 +148,15 @@ def ec2_metadata_disabled?
       ENV.fetch('AWS_EC2_METADATA_DISABLED', 'false').downcase == 'true'
     end
 
-    def resolve_backoff(backoff)
-      case backoff
-      when Proc then backoff
-      when Numeric then ->(_) { Kernel.sleep(backoff) }
-      else ->(num_failures) { Kernel.sleep(1.2**num_failures) }
-      end
-    end
-
-    def retry_errors(&_block)
+    def retry_json_errors(&_block)
       attempts = 0
-      unretryable_errors = [
-        EC2Metadata::TokenRetrievalError,
-        EC2Metadata::MetadataNotFoundError,
-        EC2Metadata::RequestForbiddenError
-      ]
-
       begin
         yield
       rescue Aws::Json::ParseError
-        raise Aws::Errors::MetadataParserError unless attempts < @retries
+        raise unless attempts < 3
 
-        @backoff.call(attempts)
         attempts += 1
         retry
-      rescue *unretryable_errors => e
-        warn("Error retrieving instance profile credentials: #{e}")
-        '{}'
-      rescue StandardError
-        if attempts < @retries
-          @backoff.call(attempts)
-          attempts += 1
-          retry
-        else
-          warn("Error retrieving instance profile credentials: #{e}")
-          '{}'
-        end
       end
     end
   end