| # Skywalking with Kotlin coroutine |
| This Plugin provides an auto instrument support plugin for Kotlin coroutine based on context snapshot. |
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| ## Description |
| SkyWalking provide tracing context propagation inside thread. In order to support Kotlin Coroutine, we provide this additional plugin. |
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| ## Implementation principle |
| As we know, Kotlin coroutine switches the execution thread by `CoroutineDispatcher`. |
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| 01. Create a snapshot of the current context before dispatch the continuation. |
| 02. Then create a coroutine span after thread switched, mark the span continued with the snapshot. |
| 03. Every new span which created in the new thread will be a child of this coroutine span. So we can link those span together in a tracing. |
| 04. After the original runnable executed, we need to stop the coroutine span for cleaning thread state. |
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| ## Some screenshots |
| ### Run without the plugin |
| We run a Kotlin coroutine based gRPC server without this coroutine plugin. |
| You can find, the one call (client -> server1 -> server2) has been split two tracing paths. |
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| 01. Server1 without exit span and server2 tracing path. |
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| 02. Server2 tracing path. |
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| ### Run with the plugin |
| Without changing codes manually, just install the plugin. We can find the spans be connected together. We can get all info of one client call. |
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