Simplify decoder logic for empty create constructor. Update documentation.

amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/config/AwsCredentialsProviderPropertyValueDecoder.java

@@ -99,27 +99,34 @@ class AwsCredentialsProviderPropertyValueDecoder implements IPropertyValueDecode
                 final String[] varargs = Arrays.copyOfRange(nameAndArgs, 1, nameAndArgs.length);
 
                 // attempt to invoke an explicit N-arg constructor of FooClass(String, String, ...)
-                provider = constructProvider(
+                provider = constructProvider(providerName, () -> {
-                        providerName,
+                    Class<?>[] argTypes = new Class<?>[nameAndArgs.length - 1];
-                        () -> {
+                    Arrays.fill(argTypes, String.class);
-                            Class<?>[] argTypes = new Class<?>[nameAndArgs.length - 1];
+                    return clazz.getConstructor(argTypes).newInstance(varargs);
-                            Arrays.fill(argTypes, String.class);
+                });
-                            return clazz.getConstructor(argTypes).newInstance(varargs);
-                        },
-                        clazz);
 
                 if (provider == null) {
                     // attempt to invoke a public varargs/array constructor of FooClass(String[])
-                    provider = constructProvider(
+                    provider = constructProvider(providerName, () -> clazz.getConstructor(String[].class)
-                            providerName,
+                            .newInstance((Object) varargs));
-                            () -> clazz.getConstructor(String[].class).newInstance((Object) varargs),
-                            clazz);
                 }
             }
 
             if (provider == null) {
-                // regardless of parameters, fallback to invoke a public no-arg constructor
+                // fallback to invoke a public no-arg constructor
-                provider = constructProvider(providerName, clazz::newInstance, clazz);
+                provider = constructProvider(providerName, clazz::newInstance);
+            }
+
+            if (provider == null) {
+                // if still not found, try empty create() method
+                try {
+                    Method createMethod = clazz.getDeclaredMethod("create");
+                    if (Modifier.isStatic(createMethod.getModifiers())) {
+                        provider = constructProvider(providerName, () -> clazz.cast(createMethod.invoke(null)));
+                    }
+                } catch (NoSuchMethodException e) {
+                    // No create() method found for class
+                }
             }
 
             if (provider != null) {
@@ -145,17 +152,18 @@ class AwsCredentialsProviderPropertyValueDecoder implements IPropertyValueDecode
 
     private static List<String> getPossibleFullClassNames(final String provider) {
         return Stream.of(
-                        // Customer provides a short name of common providers in com.amazonaws.auth package
-                        // (e.g., any classes implementing the AWSCredentialsProvider interface)
-                        // @see
-                        // http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/AWSCredentialsProvider.html
-                        "com.amazonaws.auth.",
-
                         // Customer provides a short name of a provider offered by this multi-lang package
                         "software.amazon.kinesis.multilang.auth.",
+                        // Customer provides a short name of common providers in software.amazon.awssdk.auth.credentials
+                        // package (e.g., any classes implementing the AWSCredentialsProvider interface)
+                        // @see
+                        // https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/auth/credentials/AwsCredentialsProvider.html
                         "software.amazon.awssdk.auth.credentials.",
                         // Customer provides a fully-qualified provider name, or a custom credentials provider
-                        // (e.g., com.amazonaws.auth.ClasspathFileCredentialsProvider, org.mycompany.FooProvider)
+                        // (e.g., software.amazon.awssdk.auth.credentials.AwsCredentialsProvider)
+
+                        //  Sts auth provider
+                        "software.amazon.awssdk.services.sts.auth.",
                         "")
                 .map(prefix -> prefix + provider)
                 .collect(Collectors.toList());
@@ -173,39 +181,18 @@ class AwsCredentialsProviderPropertyValueDecoder implements IPropertyValueDecode
      * @param providerName Raw, unmodified provider name. Should there be an
      *      Exception during construction, this parameter will be logged.
      * @param constructor supplier-like function that will perform the construction
-     * @param clazz the class to attempt to construct
      * @return the constructed provider, if successful; otherwise, null
      *
      * @param <T> type of the CredentialsProvider to construct
      */
     private static <T extends AwsCredentialsProvider> T constructProvider(
-            final String providerName,
+            final String providerName, final CredentialsProviderConstructor<T> constructor) {
-            final CredentialsProviderConstructor<T> constructor,
-            Class<? extends AwsCredentialsProvider> clazz) {
         try {
             // Try to create an instance using the given constructor
             return constructor.construct();
-        } catch (InstantiationException e) {
-            try {
-                // Try to create an instance using .create()
-                Method createMethod = clazz.getDeclaredMethod("create");
-                if (Modifier.isStatic(createMethod.getModifiers())) {
-                    Object provider = createMethod.invoke(null);
-                    if (provider instanceof AwsCredentialsProvider) {
-                        return (T) provider;
-                    } else {
-                        log.warn("Returned provider is not an instance of {}", AwsCredentialsProvider.class.getName());
-                        return null;
-                    }
-                } else {
-                    log.warn("Found non-static create() method in {}", providerName);
-                }
-            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e1) {
-                log.warn("Exception thrown by create() method in {}", providerName, e1.getCause());
-            }
         } catch (NoSuchMethodException ignored) {
             // ignore
-        } catch (IllegalAccessException | InvocationTargetException | RuntimeException e) {
+        } catch (IllegalAccessException | InvocationTargetException | InstantiationException | RuntimeException e) {
             log.warn("Failed to construct {}", providerName, e);
         }
         return null;

amazon-kinesis-client-multilang/src/test/resources/multilang.properties

@@ -19,7 +19,7 @@ applicationName = MultiLangTest
 # Users can change the credentials provider the KCL will use to retrieve credentials.
 # The DefaultAWSCredentialsProviderChain checks several other providers, which is
 # described here:
-# http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/DefaultAWSCredentialsProviderChain.html
+# https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/auth/credentials/DefaultCredentialsProvider.html
 AWSCredentialsProvider = DefaultCredentialsProvider
 
 # Appended to the user agent of the KCL. Does not impact the functionality of the

docs/multilang/configuring-credential-providers.md

@@ -7,21 +7,22 @@ However, KCL now provides better extensibility to handle, and be enhanced to han
 This document should help multilang customers configure a suitable `CredentialProvider` (or contribute changes to support a new use case!).
 
 ## Sample Provider Configuration
+DEPRECATED: StsAssumeRoleCredentialsProvider can no longer be constructed in this way:
+```
+AWSCredentialsProvider = StsAssumeRoleCredentialsProvider|<arn>|<sessionName>`
+```
 
-In a Properties file, an `AWSCredentialsProperty` configuration might look like:
+To create a [StsAssumeRoleCredentialsProvider][sts-assume-provider], see KclStsAssumeRoleCredentialsProvider below.
-```
-AWSCredentialsProvider = STSAssumeRoleSessionCredentialsProvider|<arn>|<sessionName> 
-```
-This basic configuration creates an [STSAssumeRoleSessionCredentialsProvider][sts-assume-provider] with an ARN and session name.
-While functional, this configuration is limited.
-For example, this configuration cannot set a regional endpoint (e.g., VPC use case).
 
-Leveraging nested properties, an `AWSCredentialsProperty` value might change to:
+You can create a default [DefaultCredentialsProvider][default-credentials-provider] or [AnonymousCredentialsProvider][anonymous-credentials-provider]
+by passing it in the config like:
 ```
-AWSCredentialsProvider = KclSTSAssumeRoleSessionCredentialsProvider|<arn>|<sessionName>\
+AWSCredentialsProvider = DefaultCredentialsProvider
-    |endpointRegion=us-east-1|externalId=spartacus
 ```
-N.B. Backslash (`\`) is for multi-line legibility and is not required.
+
+If you wish to customize properties on an AWS SDK provider that uses a builder, like the StsASsumeRoleCredentialsProvider,
+you will need to wrap this provider class, provide a constructor, and manage the build of the provider. 
+See implementation of [KclStsAssumeRoleCredentialsProvider][kcl-sts-provider]
 
 ## Nested Properties
 
@@ -36,9 +37,6 @@ The [Backus-Naur form][bnf] of the value:
 <nested-value ::= <string> # this depends on the nested key
 ```
 
-In general, required parameters are passed directly to the class' constructor
-(e.g., [STSAssumeRoleSessionCredentialsProvider(String, String)][sts-assume-provider-constructor]).
-
 Nested properties are a custom mapping provided by KCL multilang, and do not exist in the AWS SDK.
 See [NestedPropertyKey][nested-property-key] for the supported keys, and details on their expected values.
 
@@ -54,18 +52,26 @@ A backwards-compatible addition might look like:
     }
 ```
 
-### KclSTSAssumeRoleSessionCredentialsProvider
+Leveraging nested properties, an `AWSCredentialsProperty` value might look like:
-
-KCL multilang includes a [custom nested property processor for `STSAssumeRole`][kcl-sts-provider].
-Multilang configurations that use `STSAssumeRoleSessionCredentialsProvider` need only prefix `Kcl` to exercise this new provider:
 ```
-AWSCredentialsProvider = KclSTSAssumeRoleSessionCredentialsProvider|<arn>|<sessionName>
+AWSCredentialsProvider = KclSTSAssumeRoleSessionCredentialsProvider|<arn>|<sessionName>\
+    |endpointRegion=us-east-1|externalId=spartacus
+```
+
+N.B. Backslash (`\`) is for multi-line legibility and is not required.
+### KclStsAssumeRoleCredentialsProvider
+
+KCL multilang includes a [custom nested property processor for `StsAssumeRole`][kcl-sts-provider].
+Multilang configurations that use `StsAssumeRoleSessionCredentialsProvider` need only prefix `Kcl` to exercise this new provider:
+```
+AWSCredentialsProvider = KclStsAssumeRoleCredentialsProvider|<arn>|<sessionName>
 ```
 
 [aws-credentials-provider]: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/auth/credentials/AwsCredentialsProvider.html
 [bnf]: https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form
-[kcl-sts-provider]: /amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/auth/KclSTSAssumeRoleSessionCredentialsProvider.java
+[kcl-sts-provider]: /amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/auth/KclStsAssumeRoleCredentialsProvider.java
 [nested-property-key]: /amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/NestedPropertyKey.java
 [nested-property-processor]: /amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/NestedPropertyProcessor.java
-[sts-assume-provider]: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/STSAssumeRoleSessionCredentialsProvider.html
+[sts-assume-provider]: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/sts/auth/StsAssumeRoleCredentialsProvider.html
-[sts-assume-provider-constructor]: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/STSAssumeRoleSessionCredentialsProvider.html#STSAssumeRoleSessionCredentialsProvider-java.lang.String-java.lang.String-
+[default-credentials-provider]: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/auth/credentials/DefaultCredentialsProvider.html
+[anonymous-credentials-provider]: https://sdk.amazonaws.com/java/api/2.0.0-preview-11/software/amazon/awssdk/auth/credentials/AnonymousCredentialsProvider.html