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Simplify decoder logic for empty create constructor. Update documentation.

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This commit is contained in:
Ethan Katnic 2024-08-29 15:46:42 -07:00
parent 444a4ddf9a
commit 921781b9f9
3 changed files with 60 additions and 67 deletions
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75
amazon-kinesis-client-multilang/src/main/java/software/amazon/kinesis/multilang/config/AwsCredentialsProviderPropertyValueDecoder.java
View file

@ -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(
providerName,
() -> {
Class<?>[] argTypes = new Class<?>[nameAndArgs.length - 1];
Arrays.fill(argTypes, String.class);
return clazz.getConstructor(argTypes).newInstance(varargs);
},
clazz);
provider = constructProvider(providerName, () -> {
Class<?>[] argTypes = new Class<?>[nameAndArgs.length - 1];
Arrays.fill(argTypes, String.class);
return clazz.getConstructor(argTypes).newInstance(varargs);
});
if (provider == null) {
// attempt to invoke a public varargs/array constructor of FooClass(String[])
provider = constructProvider(
providerName,
() -> clazz.getConstructor(String[].class).newInstance((Object) varargs),
clazz);
provider = constructProvider(providerName, () -> clazz.getConstructor(String[].class)
.newInstance((Object) varargs));
}
}
if (provider == null) {
// regardless of parameters, fallback to invoke a public no-arg constructor
provider = constructProvider(providerName, clazz::newInstance, clazz);
// fallback to invoke a public no-arg constructor
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 CredentialsProviderConstructor<T> constructor,
Class<? extends AwsCredentialsProvider> clazz) {
final String providerName, final CredentialsProviderConstructor<T> constructor) {
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;

2
amazon-kinesis-client-multilang/src/test/resources/multilang.properties
View file

@ -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

50
docs/multilang/configuring-credential-providers.md
View file

@ -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:
```
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).
To create a [StsAssumeRoleCredentialsProvider][sts-assume-provider], see KclStsAssumeRoleCredentialsProvider below.
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>\
|endpointRegion=us-east-1|externalId=spartacus
AWSCredentialsProvider = DefaultCredentialsProvider
```
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
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:
Leveraging nested properties, an `AWSCredentialsProperty` value might look like:
```
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-constructor]: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/STSAssumeRoleSessionCredentialsProvider.html#STSAssumeRoleSessionCredentialsProvider-java.lang.String-java.lang.String-
[sts-assume-provider]: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/sts/auth/StsAssumeRoleCredentialsProvider.html
[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