Hello KTor Team! I wanted to check with on couple...

# ktor

[Vinay Pothnis]

Hello KTor Team!

I wanted to check with on couple of things related to ktor-client and the best practices around it.

1. Whats the right way to re-use connections (or use a connection pool) with CIOEngine ? I am using the following configs:

engine {
    maxConnectionsCount = 250
    pipelining = true
    endpoint {
      maxConnectionsPerRoute = 100
      pipelineMaxSize = 20
      keepAliveTime = 5000
      connectTimeout = 5000
      connectAttempts = 5
      threadsCount = 20
    }
  }

It looks like without the pipielining = true flag, new connections were being created for every request/call.
Are these sufficient or is there any other config that I would need to set to effectively re-use connections?

2. Whats the recommended way to use client.close() or client.use {} - Especially when we are sharing/re-using the HttpClient
I went through the docs here - https://ktor.io/docs/client.html#close-client
With a shared HttpClient - if I used client.use {} - i was seeing errors on subsequent requests after some initial successful requests.
Errors like - kotlinx.coroutines.JobCancellationException: Parent job is Completed; job=JobImpl{Completed}@5e4f8454

So, when should this actually be used? During shutdown to release/cleanup the resources?

Thanks so much for your help with this!

[Aleksei Tirman [JB]]

2. The use extension function just executes the block and then closes a client. So if you want to share a client make sure to close it after making all necessary requests.

[Aleksei Tirman [JB]]

By the way, the CIO engine is not production-ready.

[Vinay Pothnis]

@Aleksei Tirman [JB] thanks so much for your inputs!

Oh! I see, thanks for the note on CIO engine.

[Vinay Pothnis]

I see that the OkHTTP is listed as applicable for Android in the docs. Can this be used for JVM (non Android) as well?

I see that Jetty Engine only supports Http2.

So, that leaves only the Apache Engine. I wasn’t sure if that supported connection pooling. (At least it wasn’t evident from the docs)

Wondering what would be your recommendation for a production ready engine that can support connection pooling/reuse?

[Aleksei Tirman [JB]]

OkHttp engine could be used for JVM (non Android).

Wondering what would be your recommendation for a production ready engine that can support connection pooling/reuse?

I don't actually know. @e5l could you please help with advice?

[Vinay Pothnis]

OkHttp engine could be used for JVM (non Android).

Thanks @Aleksei Tirman [JB]!

[e5l]

Apache engine is also good option

[Vinay Pothnis]

Gotcha! Thanks @e5l !

[Lucas Milotich]

I have been using ktor apache since this year, after some tuning options I can say it has a good performance

[Lucas Milotich]

You can configure reuse connection strategy, keep alive strategy, io threads, etc