management client does not support adding custom policies

[zhoxing-ms]

• Package Name: azure-core
• Package Version: 1.13.0
• Operating System: All
• Python Version: All

Describe the bug
Although a PR has added the ability to add the custom policies when no specified policies are passed in through **kwargs to the PipelineClient.
PR link: #17340

However, management client still does not support adding custom policies.
For example, the per_call_policies or per_retry_policies is passed in through **kwargs when building ResourceManagementClient. The reason for this issue is as follows:

1. In method __init__() of ResourceManagementClient, the ARMPipelineClient is created
   

   azure-sdk-for-python/sdk/resources/azure-mgmt-resource/azure/mgmt/resource/resources/_resource_management_client.py

   Line 80 in 6025370

   self._client = ARMPipelineClient(base_url=base_url, config=self._config, **kwargs)

2. When creating ARMPipelineClient, if the specified policies are not passed in through **kwargs, the default policies will be added to **kwargs before building the pipeline
   

   azure-sdk-for-python/sdk/core/azure-mgmt-core/azure/mgmt/core/_pipeline_client.py

   Lines 44 to 51 in 6025370

   	def __init__(self, base_url, **kwargs):
   	if "policies" not in kwargs:
   	if "config" not in kwargs:
   	raise ValueError(
   	"Current implementation requires to pass 'config' if you don't pass 'policies'"
   	)
   	kwargs["policies"] = self._default_policies(**kwargs)
   	super(ARMPipelineClient, self).__init__(base_url, **kwargs)

3. When building pipeline, only when there are no policies in **kwargs, there is logic to add custom policies. Since the default policies are passed in through **kwargs in step 2, so there is no logic to add custom policies.
   

   azure-sdk-for-python/sdk/core/azure-core/azure/core/_pipeline_client.py

   Lines 111 to 117 in 6025370

   	def _build_pipeline(self, config, **kwargs): # pylint: disable=no-self-use
   	transport = kwargs.get('transport')
   	policies = kwargs.get('policies')
   	if policies is None: # [] is a valid policy list
   	per_call_policies = kwargs.get('per_call_policies', [])
   	per_retry_policies = kwargs.get('per_retry_policies', [])

Expected behavior
Could we consider that when building pipeline client, if the specified policies are passed in through **kwargs, these policies (in ARMPipelineClient, they are the default policies set by _default_policies) can also support appending custom policies?

ETA
Because this issue affects our migration of track 2 for resource module, and we plan to complete the merge of the migrated code by next Monday.
So this is an urgent issue and we hope to have it resolved by next Monday. Otherwise, we have to add custom policies by modifying private variables which do not conform to the code specification.

[iscai-msft]

I think this functionality should help you. You can pass in policies with per_call_policies and per_retry_policies. This was added in version 1.13.0, so you guys may have to update your azure-core dependency.

cc @xiangyan99 @lmazuel for confirmation

[xiangyan99]

I think the design that "only policies is not specified, we will honor custom policies" is correct.

In your case, I would suggest you supporting custom_policies in your _default_policies(config, **kwargs)

azure-sdk-for-python/sdk/core/azure-mgmt-core/azure/mgmt/core/_pipeline_client.py

Lines 54 to 69 in 6025370

	def _default_policies(config, **kwargs):
	return [
	RequestIdPolicy(**kwargs),
	ARMAutoResourceProviderRegistrationPolicy(),
	config.headers_policy,
	config.user_agent_policy,
	config.proxy_policy,
	ContentDecodePolicy(**kwargs),
	config.redirect_policy,
	config.retry_policy,
	config.authentication_policy,
	config.custom_hook_policy,
	config.logging_policy,
	DistributedTracingPolicy(**kwargs),
	config.http_logging_policy or ARMHttpLoggingPolicy(**kwargs),
	]

Does this make sense?

[xiangyan99]

Fixed.