HTTPClient(s) in the Connector should be pooled

[cleemullins]

The class EndorsementsRetriever.cs creates a new HttpClient for each request. This is wasteful of resources, and significantly increases latency.

This should be pooled and/or static.

[RyanDawkins]

Looks like this can be closed.

[cleemullins]

Not quite yet. There is 1 left. :)

…

________________________________ From: Ryan Dawkins <notifications@github.com> Sent: Tuesday, February 20, 2018 9:00:16 PM To: Microsoft/botbuilder-dotnet Cc: Chris Mullins; Assign Subject: Re: [Microsoft/botbuilder-dotnet] HTTPClient(s) in the Connector should be pooled (#60) Looks like this can be closed. — You are receiving this because you were assigned. Reply to this email directly, view it on GitHub<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FMicrosoft%2Fbotbuilder-dotnet%2Fissues%2F60%23issuecomment-367214087&data=04%7C01%7Ccmullins%40microsoft.com%7C8c1bc524c2b14c24ee2608d578e8009a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636547860200252291%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwifQ%3D%3D%7C-1&sdata=%2B4Sx9IAWpJckGPi4WgWUoq6iE74g72YLlzBQBhhFXEg%3D&reserved=0>, or mute the thread<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FABHICXjSK2IuVxgLyI_ir_snGGNevFCTks5tW6LggaJpZM4R51D6&data=04%7C01%7Ccmullins%40microsoft.com%7C8c1bc524c2b14c24ee2608d578e8009a%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636547860200252291%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwifQ%3D%3D%7C-1&sdata=gqZJo1WDRMEk%2FXsaOmhK9n%2BuRhwAOgl3O3ImKTH7QsU%3D&reserved=0>.

[cleemullins]

The remaining one to fix is the ConnectorClient. It's called in few places.

@EricDahlvang is looking into this now. It's complex because it's down in auto-generated code and the patterns for fixing it are non-obvious.

[EricDahlvang]

In August, a constructor was introduced to ServiceClient that allowed consuming code to specify if HttpClient should be disposed https://github.com/Azure/azure-sdk-for-net/pull/3547/files . A method was also added that ensures ProductInfoHeaderValues are not added to UserAgent twice. However, this throws exceptions when a ProductInfoHeaderValue is provided that does not have a Product (i.e. constructed with comment only). Also, the ServiceClient itself adds a ProductInfoHeaderValue every time. These things make the HttpClient constructor on ServiceClient an invalid option for re-using a static HttpClient . ( filed this issue: Azure/azure-sdk-for-net#4086 and this PR Azure/azure-sdk-for-net#4095 )

These things considered, the only viable option at this time is something like what @tomlm submitted here: https://github.com/Microsoft/BotBuilder/blob/d09bcc9c46e2a16d9d523f4209387fd0aaa68b29/CSharp/Library/Microsoft.Bot.Connector.Shared/ConnectorClientEx.cs

[cleemullins]

With Tom's most recent changes, #186, this is now done.
@EricDahlvang