Ktor Client 3.0 Support

[sausti]

Feature description

1. Our multiplatform app uses Ktor Client to make network requests. We've integrated with Datadog's SDK instrumentation for Ktor.
2. Datadog's SDK implementation only supports Ktor 2.0 and not the recently released Ktor 3.0. We are unable to update our Ktor Client to version 3.0 because of this.
3. We'd like to see support for the Ktor 3.0 client.

Proposed solution

Update the Ktor dependency to 3.0.*+, or create a separate dedicated library for Ktor 3.0.

Other relevant information

No response

[0xnm]

Hello @sausti!

Thanks for reporting it. We will estimate the changes needed and add the necessary support.

[0xnm]

Hi @sausti! Can you please post the error you have?

By looking on the migration guide I can see that only binary-incompatible change for the Ktor Client is the rename of the HttpRespose#content property, which our instrumentation is not using.

At least I'm able to compile and run our instrumentation with Ktor 3.x without any changes.

[sausti]

Thank you for the help @0xnm! Android compiles and runs as expected when targeting Ktor 3.0.3, but on iOS, we see the following:

Uncaught Kotlin exception: kotlin.native.internal.IrLinkageError: Constructor 'AttributeKey.<init>' can not be called: No constructor found for symbol 'io.ktor.util/AttributeKey.<init>|<init>(kotlin.String){}[0]'
    at 0   App.debug.dylib                   0x10bdcaaa7        kfun:kotlin.Throwable#<init>(kotlin.String?){} + 99 
    at 1   App.debug.dylib                   0x10bdc483b        kfun:kotlin.Error#<init>(kotlin.String?){} + 95 
    at 2   App.debug.dylib                   0x10bdfe9eb        kfun:kotlin.native.internal.IrLinkageError#<init>(kotlin.String?){} + 95 
    at 3   App.debug.dylib                   0x10bdfeaa3        kfun:kotlin.native.internal#ThrowIrLinkageError(kotlin.String?){}kotlin.Nothing + 163 
    at 4   App.debug.dylib                   0x10d99b327        kfun:com.datadog.kmp.ktor.internal.plugin.DatadogKtorPlugin.Companion.<init>#internal + 115 
    at 5   App.debug.dylib                   0x10d999163        kfun:com.datadog.kmp.ktor.internal.plugin.DatadogKtorPlugin.$init_global#internal + 131 
    at 6   App.debug.dylib                   0x10bf88be3        CallInitGlobalPossiblyLock + 563 
    at 7   App.debug.dylib                   0x10d999273        kfun:com.datadog.kmp.ktor.internal.plugin.DatadogKtorPlugin#<init>(com.datadog.kmp.rum.RumMonitor;kotlin.collections.Map<kotlin.String,kotlin.collections.Set<com.datadog.kmp.ktor.TracingHeaderType>>;com.datadog.kmp.ktor.sampling.Sampler;com.datadog.kmp.ktor.internal.trace.TraceIdGenerator;com.datadog.kmp.ktor.internal.trace.SpanIdGenerator;com.datadog.kmp.ktor.RumResourceAttributesProvider){} + 219 
    at 8   App.debug.dylib                   0x10d99739b        kfun:com.datadog.kmp.ktor#datadogKtorPlugin(kotlin.collections.Map<kotlin.String,kotlin.collections.Set<com.datadog.kmp.ktor.TracingHeaderType>>;kotlin.Float;com.datadog.kmp.ktor.RumResourceAttributesProvider){}io.ktor.client.plugins.api.ClientPlugin<kotlin.Unit> + 523 
    at 9   App.debug.dylib                   0x10d99757f        kfun:com.datadog.kmp.ktor#datadogKtorPlugin$default(kotlin.collections.Map<kotlin.String,kotlin.collections.Set<com.datadog.kmp.ktor.TracingHeaderType>>?;kotlin.Float;com.datadog.kmp.ktor.RumResourceAttributesProvider?;kotlin.Int){}io.ktor.client.plugins.api.ClientPlugin<kotlin.Unit> + 391 
...

Which is odd, as AttributeKey's (Use in Datadog) signature has not changed from Ktor 2 to Ktor 3? Perhaps this is due to a different linking error caused by mismatched versions on iOS?

[0xnm]

It is inline function and actually under the hood the captured type definition changed in the Ktor 3.x release.

I'm wondering though if it is possible to solve this issue completely on the client side, by leveraging linking flags, will check it out.