[v2] Add configuration to disable host prefix injection

[kdaily]

Issue #, if available:

Port of boto/botocore#3405

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.

Edit: Chatted offline about setting env vars/config file. Decided we're okay with current tests.

[ashovlin]

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

[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

[kdaily]

Marking as draft pending review and approval of PR in botocore:

boto/botocore#3405

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (619640c) to head (b729c01).
Report is 36 commits behind head on v2.

Additional details and impacted files

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##   v2   #9268   +/-   ##
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