[Draft] tower_service::Service <-> warp::Filter interop

[jxs]

I continued the work started on #70 to try and make tower_service::Service's run on warp and the ability to run warp::Filter's as a service on Hyper.

Notes

• to be able to call tower_service::Service::call(&mut self, req: Request) I had to remove the Arc usage and Clone to the trait bounds, I benchmarked and results seemed similar benchmarking the hello world example with --release:

(with Arc)

$ wrk -t4 -c1000 -d30s --latency http://127.0.0.1:3030
Running 30s test @ http://127.0.0.1:3030
  4 threads and 1000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     4.34ms    3.79ms  82.56ms   87.93%
    Req/Sec    12.71k     3.47k   22.53k    65.86%
  Latency Distribution
     50%    3.19ms
     75%    5.16ms
     90%    8.69ms
     99%   18.67ms
  1519131 requests in 30.06s, 188.34MB read
  Socket errors: connect 751, read 114, write 2, timeout 0
Requests/sec:  50530.67
Transfer/sec:      6.26MB

(with Clone)

$ wrk -t4 -c1000 -d30s --latency http://127.0.0.1:3030
Running 30s test @ http://127.0.0.1:3030
  4 threads and 1000 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency     4.31ms    2.95ms  41.62ms   81.27%
    Req/Sec    12.68k     3.62k   22.61k    60.70%
  Latency Distribution
     50%    3.57ms
     75%    5.20ms
     90%    8.03ms
     99%   14.95ms
  1517745 requests in 30.08s, 188.17MB read
  Socket errors: connect 751, read 102, write 42, timeout 0
Requests/sec:  50463.45
Transfer/sec:      6.26MB

• I looked into Consider removal of warp::ext::set #222 and since the WarpService trait already existed and is also passing the remote_addr extra argument, so I impled WarpService for T: tower_service::Service , when a Service is called via warp remote_addr(or other future arguments's, see Add warp::tls::peer_certificates() filter. #318) is discarded

• impl WarpService for T: tower_service::Service requires tower_service::Service::Error : warp::Reject that seemed to be the simplest way to then integrate Service errors with warp's logging and error handling, should another error be used/should Reject be impled for T?

• I think there still needs to be developed a way to compose warp::Filter's with tower_service::Service's, but maybe that could be done after closing the interop API?

[LucioFranco]

You could use service_fn as an example here

[seanmonstar]

Thanks for the draft, I used what you had here in #367.

[jxs]

awesome! do you plan to impl Filter for Service on a following PR?

[seanmonstar]

I'm not so sure there needs to be a conversion the other way around, one can svc.call inside a filter.and_then if need be.