replace restbed by restinio

Parts

OpenDHT: https://github.com/savoirfairelinux/opendht/pull/403 (merged)
Jami-daemon: https://review.jami.net/#/c/ring-daemon/+/11959/ (in review)

Tasks

~~Find an alternative~~
~~Test async over a threadpool~~
~~Basic methods & threading~~
~~Compile OpenDHT in c++14~~
~~Add RESTinio to OpenDHT~~
~~Fix flush happening after async scope~~
~~Server: Get,Put,Info,Stats,Options,PutEncrypted,PutSigned,Subscribe,Filter,Listen,Push~~
~~Server: Cancel disconnected listeners by detecting a closed connection, Replace Thread~~
~~Server: Replace Scheduler task by Asio Timer making the entire server on one io_context that is run on one thread.~~
~~Make an async RESTinio client with callbacks & integrate http_parser~~
~~Rewrite client side with an in-house std::async client library~~
~~Adapt and test the behavior of proxy client to new async design~~
~~Verify that keep alive is working~~
~~Patch for ISSUE-552: Configure the server to send keep alive every X min when X < 15 min)~~
~~Make the RESTful API backward compatible to non-standard HTTP methods~~
~~Redirect server logging~~
~~IPV6 support: client & server~~
~~Make dhtproxytests pass~~
~~Add docker setup for restinio & http_parser fork for Travis-CI~~
~~Benchmark the proxy server~~
~~Replace Jami-daemon nameserver RESTbed by new OpenDHT Async Client~~
~~Add OpenSSL to OpenDHT CMake & Autotools~~
~~Implement OpenSSL in http lib (bridge GNUTLS Identity/Cert to OpenSSL in Asio)~~
~~Implement HTTPS in DHTProxy (upstream is HTTP)~~
~~Use HTTP or HTTPS depending on generated dht:crypto:Identity (-i)~~
~~Write Docker files for OpenDHT with Travis CI~~
~~Integrate to the daemon autotools build system along with contribs (fmt, http_parser, restinio, ssl)~~
~~Cross-compile on Jenkins: Linux, Arm, OSx, Windows~~

Benchmark

10'000 requests with concurrency of 20 requests

Compiled with:

cmake -DOPENDHT_TESTS=ON -DOPENDHT_PROXY_SERVER=ON -DOPENDHT_PROXY_CLIENT=ON -DCMAKE_INSTALL_PREFIX=/usr -DOPENDHT_PROXY_SERVER_IDENTITY=ON -DOPENDHT_DOCUMENTATION=Off -DOPENDHT_PUSH_NOTIFICATIONS=ON -DCMAKE_BUILD_TYPE=Release ../

Summary

max_pipelined_requests: 16
concurrent_accepts_count: 15

REST framework	Requests per second
RESTbed (multi-threded)	12'677
RESTinio (one io_context thread)	18'834
RESTinio (io_context on thread pool)	12'719

max_pipelined_requests: 7
concurrent_accepts_count: 6

REST framework	Requests per second
RESTbed (multi-threded)	12'677
RESTinio (one io_context thread)	17'472
RESTinio (io_context on thread pool)	11'800

Restbed: multi-threaded

Server Software:        
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        180 bytes

Concurrency Level:      20
Time taken for tests:   0.789 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      2870000 bytes
HTML transferred:       1800000 bytes
Requests per second:    12677.48 [#/sec] (mean)
Time per request:       1.578 [ms] (mean)
Time per request:       0.079 [ms] (mean, across all concurrent requests)
Transfer rate:          3553.16 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    1   0.2      1       3
Processing:     0    1   0.4      1      13
Waiting:        0    1   0.3      1      10
Total:          1    2   0.5      1      13
WARNING: The median and mean for the total time are not within a normal deviation
        These results are probably not that reliable.

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      2
  80%      2
  90%      2
  95%      2
  98%      3
  99%      4
 100%     13 (longest request)

Restinio

max_pipelined_requests: 16
concurrent_accepts_count: 15

one thread for one io_context

Server Software:        RESTinio
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        172 bytes

Concurrency Level:      20
Time taken for tests:   0.531 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      3130000 bytes
HTML transferred:       1720000 bytes
Requests per second:    18833.85 [#/sec] (mean)
Time per request:       1.062 [ms] (mean)
Time per request:       0.053 [ms] (mean, across all concurrent requests)
Transfer rate:          5756.83 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.2      0       3
Processing:     0    1   0.3      1       7
Waiting:        0    1   0.3      1       6
Total:          1    1   0.4      1       8

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      1
  80%      1
  90%      1
  95%      2
  98%      2
  99%      2
 100%      8 (longest request)

io_context on thread pool

Server Software:        RESTinio
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        172 bytes

Concurrency Level:      20
Time taken for tests:   0.786 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      3130000 bytes
HTML transferred:       1720000 bytes
Requests per second:    12718.92 [#/sec] (mean)
Time per request:       1.572 [ms] (mean)
Time per request:       0.079 [ms] (mean, across all concurrent requests)
Transfer rate:          3887.72 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    1   0.2      1       3
Processing:     0    1   0.7      1      14
Waiting:        0    1   0.6      1      14
Total:          1    2   0.8      1      15
WARNING: The median and mean for the total time are not within a normal deviation
        These results are probably not that reliable.

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      1
  80%      2
  90%      2
  95%      3
  98%      4
  99%      5
 100%     15 (longest request)

max_pipelined_requests: 7
concurrent_accepts_count: 6

one thread for one io_context

Server Software:        RESTinio
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        172 bytes

Concurrency Level:      20
Time taken for tests:   0.572 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      3130000 bytes
HTML transferred:       1720000 bytes
Requests per second:    17472.10 [#/sec] (mean)
Time per request:       1.145 [ms] (mean)
Time per request:       0.057 [ms] (mean, across all concurrent requests)
Transfer rate:          5340.59 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    0   0.2      0       7
Processing:     0    1   0.4      1       8
Waiting:        0    1   0.3      1       7
Total:          1    1   0.5      1       9

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      1
  80%      1
  90%      1
  95%      2
  98%      2
  99%      2
 100%      9 (longest request)

io_context on thread pool

Server Software:        RESTinio
Server Hostname:        127.0.0.1
Server Port:            8080

Document Path:          /
Document Length:        172 bytes

Concurrency Level:      20
Time taken for tests:   0.847 seconds
Complete requests:      10000
Failed requests:        0
Total transferred:      3130000 bytes
HTML transferred:       1720000 bytes
Requests per second:    11800.02 [#/sec] (mean)
Time per request:       1.695 [ms] (mean)
Time per request:       0.085 [ms] (mean, across all concurrent requests)
Transfer rate:          3606.84 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:        0    1   0.4      1       6
Processing:     0    1   1.0      1      17
Waiting:        0    1   0.8      1      16
Total:          1    2   1.1      1      19

Percentage of the requests served within a certain time (ms)
  50%      1
  66%      1
  75%      2
  80%      2
  90%      3
  95%      4
  98%      6
  99%      7
 100%     19 (longest request)

Edited Sep 10, 2019 by Vsevolod Ivanov