[v2] Add configuration to disable host prefix injection

[kdaily]

Issue #, if available:

Description of changes:

This change adds the ability to disable host prefix injection. It changes the default for inject_host_prefix in the Config object to be a True-like object DEFAULT_TRUE (from True) so that the value can be differentiated from a user-set value using the configuration precedence.

Testing

Tested with the following commands which uses an operation-specific host prefix:

1. Default case (no disable host prefix configuration set) results in the host prefix being added:

$ aws omics create-sequence-store --name "test-sequence-store1" --description "Test store" --endpoint-url https://localhost:1234/ --tags "Environment=Test"

Could not connect to the endpoint URL: "https://control-storage-localhost:1234/sequencestore"

2. Set config environment variable to False, which is the same as the default behavior:

AWS_DISABLE_HOST_PREFIX_INJECTION=False aws omics create-sequence-store --name "test-sequence-store1" --description "Test store" --endpoint-url https://localhost:1234/ --tags "Environment=Test"

Could not connect to the endpoint URL: "https://control-storage-localhost:1234/sequencestore"

3. Set config environment variable to True, which prevents the host prefix from being prepended to the endpoint URL:

$ AWS_DISABLE_HOST_PREFIX_INJECTION=True aws omics create-sequence-store --name "test-sequence-store1" --description "Test store" --endpoint-url https://localhost:1234/ --tags "Environment=Test"

Could not connect to the endpoint URL: "https://localhost:1234/sequencestore"

I also confirmed the behavior applies when using the configuration file setting disable_host_prefix_injection, and even when not using a custom endpoint URL.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[hssyoo]

Looks good, just a couple small suggestions. I'm also curious if there are existing unit/functional tests where you can actually set the environment variable or create a config file to test that they resolve correctly E2E.

[ashovlin]

Could we wait to merge until we figure out the plan for botocore? Want to understand where V1 vs. V2 will land.

[ashovlin]

Could we document the specific environment variable and setting name here?

Suggested change

	"description": "Configure if the host prefix is prepended to the request URL in the shared configuration file or via an environment variable"
	"description": "Allow disabling the prepending of the host prefix to the request URL via ``disable_host_prefix_injection`` in the shared configuration file or the ``AWS_DISABLE_HOST_PREFIX_INJECTION`` environment variable"

[kdaily]

Still need to do this - need to regenerate changelog after refactoring.

[kdaily]

Could we wait to merge until we figure out the plan for botocore? Want to understand where V1 vs. V2 will land.

We should still wait to merge once we confirm that this is going to be fine for botocore.

[kdaily]

Looks good, just a couple small suggestions. I'm also curious if there are existing unit/functional tests where you can actually set the environment variable or create a config file to test that they resolve correctly E2E.

I think we can - this should have been done for configured endpoint URLs. I'll investigate the same still.

[kdaily]

Re: functional testing when actually setting in config file or as an env variable: here's the examples we did for the configured endpoint URL. As I recall we did this specifically because this change also introduced complexity with the services section of the config file. Other params are not tested as extensively beyond what I already added here.

• In botocore: https://github.com/aws/aws-cli/blob/v2/tests/functional/botocore/configured_endpoint_urls/test_configured_endpoint_url.py
• In aws-cli: https://github.com/kdaily/aws-cli/blob/v2/tests/functional/configured_endpoint_urls/test_configured_endpoint_url.py