使用 nghttp2 调试 HTTP/2 流量

jack

在本站之前的文章中，我介绍过两种查看 HTTP/2 流量的方法：1)在 Chrome 地址栏输入 chrome://net-internals/#http2，使用 Chrome 自带的 HTTP/2 调试工具;2)使用 Wireshark 调试 HTTP/2 流量。


　　方案 1 使用方便，但受限于 Chrome 浏览器，对于 Chrome 不支持的 h2c(HTTP/2 Cleartext，没有部署 TLS 的 HTTP/2)协议无能为力。同时，这个工具显示的信息经过了解析和筛选，不够全面。而在方案 2 中，Wireshark 位于服务端和浏览器之间，充当的是中间人角色，用它查看 HTTP/2 over HTTPS 流量时，必须拥有网站私钥或者借助浏览器共享对称密钥，才能解密 TLS 流量，配置起来比较麻烦。


　　而本文要介绍的 nghttp2，是一个用 C 实现的 HTTP/2 库，支持 h2c。它可以做为其它软件的一部分，为其提供 HTTP/2 相关功能(例如 curl 的 HTTP/2 功能就是用的 nghttp2)。除此之外，它还提供了四个有用的 HTTP/2 工具：


　　nghttp：HTTP/2 客户端;


　　nghttpd：HTTP/2 服务端;


　　nghttpx：HTTP/2 代理，提供 HTTP/1、HTTP/2 等协议之间的转换;


　　h2load：HTTP/2 性能测试工具;


　　本文简单介绍 nghttp、h2load 这两个工具。


　　编译


　　nghttp2 官方文档中有详细的编译依赖说明。对于我一直在用的 Ubuntu 14.04 LTS 来说，安装依赖是一件再简单不过的事情：


sudo apt-get install g++ make binutils autoconf automake autotools-dev libtool pkg-config zlib1g-dev libcunit1-dev libssl-dev libxml2-dev libev-dev libevent-dev libjansson-dev libjemalloc-dev cython python3-dev python-setuptools



　　解决依赖问题后，获取源码并编译安装即可：


git clone https://github.com/tatsuhiro-t/nghttp2.git

cd ./nghttp2

autoreconf -i
automake
autoconf
./configure

make
sudo make install



　　一切妥当后，nghttp2 提供的几个工具就可以直接用了。


　　nghttp


　　nghttp 做为一个功能完整的 HTTP/2 客户端，非常适合用来查看和调试 HTTP/2 流量。它支持的参数很多，通过官方文档或者 nghttp -h 都能查看。最常用几个参数如下：


　　-v, --verbose，输出完整的 debug 信息；


　　-n, --null-out，丢弃下载的数据；


　　-a, --get-assets，下载 html 中的 css、js、image 等外链资源；


　　-H, --header=<HEADER>，添加请求头部字段，如 -H':method: PUT'；


　　-u, --upgrade，使用 HTTP 的 Upgrade 机制来协商 HTTP/2 协议，用于 h2c，详见下面的例子；


　　以下是使用 nghttp 访问 nghttp2 官网的结果。从调试信息中可以清晰看到 h2c 协商以及 Server Push 的整个过程：


nghttp -nvu http://nghttp2.org

[0.147] Connected
[0.147] HTTP Upgrade request
GET / HTTP/1.1
host: nghttp2.org
connection: Upgrade, HTTP2-Settings
upgrade: h2c
http2-settings: AAMAAABkAAQAAP__
accept: */*
user-agent: nghttp2/1.9.0-DEV

[0.291] HTTP Upgrade response
HTTP/1.1 101 Switching Protocols
Connection: Upgrade
Upgrade: h2c

[0.291] HTTP Upgrade success
[0.291] recv SETTINGS frame <length=12, flags=0x00, stream_id=0>
    (niv=2)
    [SETTINGS_MAX_CONCURRENT_STREAMS(0x03):100]
    [SETTINGS_INITIAL_WINDOW_SIZE(0x04):65535]
[0.291] send SETTINGS frame <length=12, flags=0x00, stream_id=0>
    (niv=2)
    [SETTINGS_MAX_CONCURRENT_STREAMS(0x03):100]
    [SETTINGS_INITIAL_WINDOW_SIZE(0x04):65535]
[0.291] send SETTINGS frame <length=0, flags=0x01, stream_id=0>
    ; ACK
    (niv=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=3>
    (dep_stream_id=0, weight=201, exclusive=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=5>
    (dep_stream_id=0, weight=101, exclusive=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=7>
    (dep_stream_id=0, weight=1, exclusive=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=9>
    (dep_stream_id=7, weight=1, exclusive=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=11>
    (dep_stream_id=3, weight=1, exclusive=0)
[0.291] send PRIORITY frame <length=5, flags=0x00, stream_id=1>
    (dep_stream_id=11, weight=16, exclusive=0)
[0.291] recv (stream_id=1) :method: GET
[0.291] recv (stream_id=1) :scheme: http
[0.291] recv (stream_id=1) :path: /stylesheets/screen.css
[0.291] recv (stream_id=1) :authority: nghttp2.org
[0.291] recv (stream_id=1) host: nghttp2.org
[0.291] recv (stream_id=1) user-agent: nghttp2/1.9.0-DEV
[0.291] recv PUSH_PROMISE frame <length=59, flags=0x04, stream_id=1>
    ; END_HEADERS
    (padlen=0, promised_stream_id=2)
[0.291] recv (stream_id=1) :status: 200
[0.291] recv (stream_id=1) date: Mon, 07 Mar 2016 13:02:35 GMT
[0.291] recv (stream_id=1) content-type: text/html
[0.291] recv (stream_id=1) content-length: 6654
[0.291] recv (stream_id=1) last-modified: Mon, 29 Feb 2016 15:38:08 GMT
[0.291] recv (stream_id=1) etag: "56d465e0-19fe"
[0.291] recv (stream_id=1) link: </stylesheets/screen.css>; rel=preload; as=stylesheet
[0.291] recv (stream_id=1) accept-ranges: bytes
[0.291] recv (stream_id=1) x-backend-header-rtt: 0.00093
[0.291] recv (stream_id=1) server: nghttpx nghttp2/1.9.0-DEV
[0.291] recv (stream_id=1) via: 2 nghttpx
[0.291] recv (stream_id=1) x-frame-options: SAMEORIGIN
[0.291] recv (stream_id=1) x-xss-protection: 1; mode=block
[0.291] recv (stream_id=1) x-content-type-options: nosniff
[0.291] recv HEADERS frame <length=251, flags=0x04, stream_id=1>
    ; END_HEADERS
    (padlen=0)
    ; First response header
[0.471] recv DATA frame <length=6654, flags=0x01, stream_id=1>
    ; END_STREAM
[0.471] recv (stream_id=2) :status: 200
[0.471] recv (stream_id=2) date: Mon, 07 Mar 2016 13:02:35 GMT
[0.471] recv (stream_id=2) content-type: text/css
[0.471] recv (stream_id=2) content-length: 39082
[0.471] recv (stream_id=2) last-modified: Mon, 29 Feb 2016 15:38:08 GMT
[0.471] recv (stream_id=2) etag: "56d465e0-98aa"
[0.471] recv (stream_id=2) accept-ranges: bytes
[0.471] recv (stream_id=2) x-backend-header-rtt: 0.000479
[0.471] recv (stream_id=2) server: nghttpx nghttp2/1.9.0-DEV
[0.471] recv (stream_id=2) via: 2 nghttpx
[0.471] recv (stream_id=2) x-frame-options: SAMEORIGIN
[0.471] recv (stream_id=2) x-xss-protection: 1; mode=block
[0.471] recv (stream_id=2) x-content-type-options: nosniff
[0.471] recv (stream_id=2) x-http2-push: 1
[0.471] recv HEADERS frame <length=61, flags=0x04, stream_id=2>
    ; END_HEADERS
    (padlen=0)
    ; First push response header
[0.964] recv DATA frame <length=16384, flags=0x00, stream_id=2>
[0.964] recv DATA frame <length=16384, flags=0x00, stream_id=2>
[0.964] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=0>
    (window_size_increment=37620)
[0.964] send WINDOW_UPDATE frame <length=4, flags=0x00, stream_id=2>
    (window_size_increment=32768)
[1.538] recv DATA frame <length=6314, flags=0x01, stream_id=2>
    ; END_STREAM
[1.538] recv SETTINGS frame <length=0, flags=0x01, stream_id=0>
    ; ACK
    (niv=0)
[1.538] send GOAWAY frame <length=8, flags=0x00, stream_id=0>
    (last_stream_id=2, error_code=NO_ERROR(0x00), opaque_data(0)=[])



　　h2load


　　h2load 是一个支持 HTTP/2 的压测工具，可以用来测试 HTTP/2 服务的稳定性、QPS 等信息。它支持的参数也可以通过官网文档或者 h2load -h 来查看。下面是一个简单例子：


BASH
h2load https://example.com -n 100 -c 10

starting benchmark...
spawning thread #0: 10 total client(s). 100 total requests
TLS Protocol: TLSv1.2
Cipher: ECDHE-RSA-AES128-GCM-SHA256
Application protocol: h2
progress: 10% done
progress: 20% done
progress: 30% done
progress: 40% done
progress: 50% done
progress: 60% done
progress: 70% done
progress: 80% done
progress: 90% done
progress: 100% done

finished in 589.98ms, 169.50 req/s, 2.19MB/s
requests: 100 total, 100 started, 100 done, 100 succeeded, 0 failed, 0 errored, 0 timeout
status codes: 100 2xx, 0 3xx, 0 4xx, 0 5xx
traffic: 1.29MB (1353790) total, 53.42KB (54700) headers (space savings 24.97%), 1.24MB (1295000) data
   min   max   mean   sd  +/- sd
time for request:    17.63ms  73.47ms  32.06ms  10.24ms    78.00%
time for connect:    81.84ms    168.23ms    119.76ms  26.44ms    60.00%
time to 1st byte:   119.09ms    201.01ms    158.06ms  23.86ms    70.00%
req/s  :   17.00    28.63    23.12  3.20    60.00%