Add a netty-4.1.x plugin to trace http

[peachisai]

Add an agent plugin to support

• Add a test case for the new plugin, refer to the doc
• Add a component id in the component-libraries.yml
• Add a logo in the UI repo

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes #.
• Update the CHANGES log.

[wu-sheng]

Before any review, I think we need a clearance from you, what is netty plugin.
Netty is a widely used TCP level framework. So in theory, there isn't a general solution to fit it, as TCP doesn't have a header to inject.

[peachisai]

Before any review, I think we need a clearance from you, what is netty plugin. Netty is a widely used TCP level framework. So in theory, there isn't a general solution to fit it, as TCP doesn't have a header to inject.

Yes, it is only tracing HTTP now. If I have rest of the time, I will provide other protocol tracings. So, is it acceptable?

[wu-sheng]

Then you should be clear for all relative codes and docs.
This is only netty-http

[peachisai]

Then you should be clear for all relative codes and docs. This is only netty-http

ok i will change those

[wu-sheng]

I want to double check, the reason that this exit span doesn't have a parent entry span, is this RPC client called in async?

[wu-sheng]

According to #625 (comment), there is a parent entry span expected. If this is caused by async, you should consider connecting the parent entry and this exit span, through application toolkit lib or some mechanism you prefer.

[wu-sheng]

@peachisai Any feedback?

[peachisai]

@peachisai Any feedback?

This week i am a little busy,i will provide feedback as soon as possible.

[wu-sheng]

So, the previous codes miss the way connecting between the main thread and netty HTTP sender channel?

[peachisai]

@peachisai Any feedback?

done

[peachisai]

So, the previous codes miss the way connecting between the main thread and netty HTTP sender channel?

Yes