* Documenting changes that resulted from issue 1475
Scott Frederick asked me to document the changes he made while implementing the changes needed for issue 1475 (https://github.com/spring-cloud/spring-cloud-config/issues/1475). This PR adds the details that Scott explained to me. Thanks, Scott. :)
* Accounting for Scott Frederick's feedback
Scott had a clarification in one spot and some more detail in another spot. I made the corresponding changes. Thanks, Scott. :)
* Add AWS S3 Environment Repository
This adds s3 as an Environment Repository.
This is based on code linked here:
https://github.com/spring-cloud/spring-cloud-config/issues/654
though it has been significantly reworked and tested.
It has been tested against vanilla buckets, versioned buckets, encrypted buckets with both AES-256 and AWS-KMS.
There are several things that I am not sure I have done 100% correctly. I'm happy to take feedback and fix. Here is a list of specific things that are known unknowns for me.
* Is there anything else that I need to do to make this implementation available in addition to what I added in EnvironmentRespositoryConfiguration?
* I added the AWS s3 java dependency for obvious reasons. There was already an AWS core dependency so I just used the same version. It is a very old version thought (2016). It seems to get the job done, but there is some stuff for STS credentials that I might use in the newer AWS SDK. I'm unsure what the process for testing the other code that requires AWS would be and updating.
* The AWS S3 client is constructed using the Default AWS provider chain. This should handle most cases implicitly (including assume role), though a newer AWS SDK might be preferable.
* This currently works against typical <app>-<profile>.properties and <app>-<profile>.yml files that are in a single AWS account and in a specified bucket. Label is optionally used as another suffix on the file name (<app>-<profile>-<label>.yml). This seems like a straight forward mapping of config server concepts to S3, but I am happy to hear other ideas. I noticed that the Git impl allows multiple repos and a kind of routing layer. This is a possibility later if needed, but this seems like a good place to start.
* I think the yaml and properties are parsed into a map correctly, but have a look at the unit tests to ensure.
* I'm trying to handle exceptional cases like other implementations when there are problems getting the config.
* In the factory I pass in ConfigServerProperties and make use of several of its attributes.
* I added the new test to AdhocTestSuite.
* I've tried serveral things, but I don't have the dependencies resolving correctly in IntelliJ Idea. I can compile and run tests with mvn on the command line, but it would be great to be able to do those things in IJ. I think that it gets confused with the parent pom in spring-cloud-build.
* Simpler YAML handling
Use YamlPropertiesFactoryBean for YAML.
Add configurable s3 endpoint.
* handle JSON config content in S3
* Label should denote a directory in S3
* Checkstyle changes, and make S3 JSON look more deliberate
Noted that JSON is using a YAML parser on purpose.
* added documentation for AWS S3 backend
* Allow overriding of AwsS3EnvironmentRepository
* put awss3 config properties at a consistent path
* Minor addition to get the new AwsS3 beans picked up during app init.
