[jira] [Comment Edited] (THRIFT-4553) are there any plans for add middle-ware support for thrift Go implementation?

["Can Celasun (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-4553?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16436847#comment-16436847 ] 

Can Celasun edited comment on THRIFT-4553 at 4/13/18 5:26 AM:
--------------------------------------------------------------

{quote}
I want to do it in BinaryProtocol, too
{quote}

The protocol doesn't matter, the transport does. For non-HTTP transports a middleware layer is not always feasible.

{quote}
do you have some suggestions?
{quote}

Yes, you can already do this by using custom processor that embeds the generated processor. For example, if you have a {{service Foo}} in your Thrift file, the generated code will have a {{Process}} method like this:

{code:go}
func (p *FooProcessor) Process(ctx context.Context, iprot, oprot thrift.TProtocol) (success bool, err thrift.TException) {
	name, _, seqId, err := iprot.ReadMessageBegin()
	if err != nil {
		return false, err
	}
	if processor, ok := p.GetProcessorFunction(name); ok {
		return processor.Process(ctx, seqId, iprot, oprot)
	}
	iprot.Skip(thrift.STRUCT)
	iprot.ReadMessageEnd()
	x247 := thrift.NewTApplicationException(thrift.UNKNOWN_METHOD, "Unknown function "+name)
	oprot.WriteMessageBegin(name, thrift.EXCEPTION, seqId)
	x247.Write(oprot)
	oprot.WriteMessageEnd()
	oprot.Flush()
	return false, x247

}
{code}

What you can do is create another processor, embed {{FooProcessor}} into it and override {{Process}}, like this:

{code:go}
type MyProcessor struct {
	*FooProcessor
}


func (p *MyProcessor) Process(ctx context.Context, iprot, oprot thrift.TProtocol) (success bool, err thrift.TException) {
	name, _, seqId, err := iprot.ReadMessageBegin()
	if err != nil {
		return false, err
	}
	if processor, ok := p.GetProcessorFunction(name); ok {
	
		// HERE: Do anything with "name" before calling processor.Process()
	
		return processor.Process(ctx, seqId, iprot, oprot)
	}
	iprot.Skip(thrift.STRUCT)
	iprot.ReadMessageEnd()
	x247 := thrift.NewTApplicationException(thrift.UNKNOWN_METHOD, "Unknown function "+name)
	oprot.WriteMessageBegin(name, thrift.EXCEPTION, seqId)
	x247.Write(oprot)
	oprot.WriteMessageEnd()
	oprot.Flush()
	return false, x247

}
{code}


was (Author: calcifer):
You can already do this by using custom processor that embeds the generated processor. For example, if you have a {{service Foo}} in your Thrift file, the generated code will have a {{Process}} method like this:

{code:go}
func (p *FooProcessor) Process(ctx context.Context, iprot, oprot thrift.TProtocol) (success bool, err thrift.TException) {
	name, _, seqId, err := iprot.ReadMessageBegin()
	if err != nil {
		return false, err
	}
	if processor, ok := p.GetProcessorFunction(name); ok {
		return processor.Process(ctx, seqId, iprot, oprot)
	}
	iprot.Skip(thrift.STRUCT)
	iprot.ReadMessageEnd()
	x247 := thrift.NewTApplicationException(thrift.UNKNOWN_METHOD, "Unknown function "+name)
	oprot.WriteMessageBegin(name, thrift.EXCEPTION, seqId)
	x247.Write(oprot)
	oprot.WriteMessageEnd()
	oprot.Flush()
	return false, x247

}
{code}

What you can do is create another processor, embed {{FooProcessor}} into it and override {{Process}}, like this:

{code:go}
type MyProcessor struct {
	*FooProcessor
}


func (p *MyProcessor) Process(ctx context.Context, iprot, oprot thrift.TProtocol) (success bool, err thrift.TException) {
	name, _, seqId, err := iprot.ReadMessageBegin()
	if err != nil {
		return false, err
	}
	if processor, ok := p.GetProcessorFunction(name); ok {
	
		// HERE: Do anything with "name" before calling processor.Process()
	
		return processor.Process(ctx, seqId, iprot, oprot)
	}
	iprot.Skip(thrift.STRUCT)
	iprot.ReadMessageEnd()
	x247 := thrift.NewTApplicationException(thrift.UNKNOWN_METHOD, "Unknown function "+name)
	oprot.WriteMessageBegin(name, thrift.EXCEPTION, seqId)
	x247.Write(oprot)
	oprot.WriteMessageEnd()
	oprot.Flush()
	return false, x247

}
{code}

> are there any plans for add middle-ware support for thrift Go implementation?
> -----------------------------------------------------------------------------
>
>                 Key: THRIFT-4553
>                 URL: https://issues.apache.org/jira/browse/THRIFT-4553
>             Project: Thrift
>          Issue Type: New Feature
>    Affects Versions: 0.11.0
>            Reporter: gansteed
>            Priority: Major
>
> version1:
> provide a function to register middleware, and chain processors all. each function can call `Next` to skip to next function. something like middle-ware implementation in gin[1]. 
> version2:
> provide two function in TSimpleServer, one for preProcess, one for afterProcess. and call them
> before and after `ok, err := processor.Process(defaultCtx, inputProtocol, outputProtocol)`, so they can use defaultCtx to do something.
>  
> middle-ware is useful for something like monitoring micro service, count execution time...etc.
>  
> [1]: https://github.com/gin-gonic/gin/blob/master/context.go#L104



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