support grpc protocol proxy #793
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localvar
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localvar and
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and removed request for
localvar
2.use emptypb instead of anypb
Codecov ReportBase: 75.89% // Head: 73.14% // Decreases project coverage by
Additional details and impacted files@@ Coverage Diff @@
## main #793 +/- ##
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- Coverage 75.89% 73.14% -2.75%
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Files 115 130 +15
Lines 13464 14969 +1505
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+ Hits 10218 10949 +731
- Misses 2674 3400 +726
- Partials 572 620 +48
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2.corrected according to review comments
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Would you mind linking an issue or concluding your change on the PR description rather than leaving it empty? |
yeah, I will supply the description of my change as soon as possible. |
pkg/protocols/grpcprot/request.go
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| // GetFirstInHeader returns the first value for a given key. | ||
| // k is converted to lowercase before searching in md. | ||
| func (r *Request) GetFirstInHeader(k string) string { | ||
| v := r.header.md.Get(k) | ||
| if v == nil { | ||
| return "" | ||
| } | ||
| return v[0] | ||
| } |
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the name of this function is a little confusing, if it is hard to find a good name, I propose removing it and using r.RawHeader().Get(k) directly
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the value structure in the grpc header is []string, so sometimes it will be necessary to obtain the first one, for reference
scg . it will be better to use r.RawHeader().GetFirst(k)
| return lb.Servers[hash.Sum32()%uint32(len(lb.Servers))] | ||
| } | ||
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| type forwardLoadBalancer struct { |
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why use the word forward?
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behavior like a forward proxy
| // Explicitly *do not Close* c2sErrChan and c2sErrChan, otherwise the select below will not terminate. | ||
| // Channels do not have to be closed, it is just a control flow mechanism, see | ||
| // https://groups.google.com/forum/#!msg/golang-nuts/pZwdYRGxCIk/qpbHxRRPJdUJ |
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it is better to close the channels in the goroutine created by sp.forwardE2E, just before it exit.
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closing the channel is not always a good option in this scenario. because the client indicates that it will not continue to send datato server on the ClientStream after called ClientStream.CloseSend, the server can take a long time to handle business before return IO.EOF or continue to send data in one direction, and the client can also continue processing , so C2S and S2C are not always sync. In this scenario, select in for loop will always select the closed channel and take a lot of CPU
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| // RequestMatcherSpec describe RequestMatcher | ||
| type RequestMatcherSpec struct { | ||
| Policy string `yaml:"policy" jsonschema:"omitempty,enum=,enum=general,enum=ipHash,enum=headerHash,enum=random"` |
This PR is for the proxy that easegress can support the gRPC protocol.
The simple process is shown in the figure above, which can forward the traffic on the gRPC client side to the downstream gRPC server according to the configured pipeline rules. It should be reminded that gRPC stream is a full-duplex protocol, so the traffic can also be pushed from the server side to the client side, the above picture is more to show the process of proxy, but not to emphasise the characteristics of full-duplex.
The main modification is the addition of the following modules:
TrafficGateinterface, managed by the Supervisor. It manages the life cycle of the runtimegrpc.serverlistener and listen for events to manage the server's life cycle, such as restart/shutdown/hot update, etc.grpc.UnknownServiceHandlerinterface to process all traffic entering theruntime, and implements the same route capability as object/httpserver/muxgRPC.Serverdoes not support tunnelling, it adopts the method of parsing headersprotocols.Request, wrappergrpc.ServerStreamprotocols.Response, wrapperstatus.Statusmetadata.md, used bygrpc.InComingContext/OutgoingContextHeadergrpc.Codecinstead ofencoding.Codec, becauseencoding.Codecwould change the header: useencoding.Codec, then header's content-type=application/grpc -> content-type=application/grpc+encoding.Codec.Name()