�ݺ�ߣ

Misultin
[pron.: Mee-sool-téen]

An Erlang library for building fast lightweight HTTP(S) servers

>-|-|(°>
Erlang User Group London - May 16th, 2011

Who am I?
Technologist and Entrepreneur. I am
particularly interested in Erlang, Python,
scalability, research, development and
integration of the multiple technologies
behind the creation of ubiquitous
computing. I’m currently co-founder
and CTO of WideTag Inc [widetag.com].

e: roberto@ostinelli.net
t: @ostinelli

What are Misultins?
Misultin are a culinary specialty of the Lake of Como.
They are lake ﬁshes that go by the latin name of Alosa
fallax lacustris, treated and cooked in a traditional
and speciﬁc way.

What is Misultin?
Misultin (pronounced mee-sool-téen) is an Erlang
library for building fast lightweight HTTP(S) servers,
which also supports websockets.

>-|-|(°>

Why another lib?
When do programmers start a new lib?

‣ Nothing similar exists
‣ Different Approach / Focus
‣ Total Control / Knowledge
‣ Experiment/Hack/Academic

Features v0.7.1
‣ Embedded, not application
‣ ~ HTTP/1.1
‣ Support for GET, POST, HEAD, PUT, DELETE, TRACE and CONNECT
‣ SSL
‣ Output compression [gzip, deﬂate]

‣ Chunked / Stream / File sending [attachment, visualization]
‣ Customizable parameters [max_connections, post_max_size, get_url_max_size, ...]

‣ Multiple servers on a single node [custom name / nameless]

‣ Websockets [also on SSL]

‣ Trapping of client closing a browser in Comet applications
‣ With / without Parametrized Modules

Code | “Hello World”
Simple “Hello World” using parametrized modules.

Code | “Hello World”
Simple “Hello World” not using parametrized modules.

Code | File Sending
Simple ﬁle sending.

Code | Websocket
1. Start Misultin specifying a Websocket loop.

Code | Websocket
2. Send the HTML + Js page.

Code | Websocket
3. Handle Websocket Data on server.

Code | Server Options
start_link(Options) -> Result

Options = [Option]
Option = {ip, list() | tuple()} |
{port, integer()} |
{name, atom()|false} |
{max_connections, integer()} |
{post_max_size, integer()} |
{get_url_max_size, integer()} |
{compress, true|false} |
{loop, fun()} |
{autoexit, true|false} |
{ws_loop, fun()|none} |
{ws_autoexit, true|false} |
{backlog, integer()} |
{acceptors_poolsize, integer()} |
{recv_timeout, integer()} |
{ssl, SslOptions}
SslOptions = [SslOption(§)]

Design | Overview
proc_lib:spawn_link/3
gen_server
Acceptor TCP Acceptor
[misultin]
. erlang:spawn/1
Acceptor
. gen_tcp:controlling_process/2
Main gen_server . call to gen_server to:
- http_pid_ref_add/2: add new pid to ref
- erlang:monitor/2: for gen_server count

Http Process Http Process Http Process HTTP Logic

erlang:spawn_link/1

HttpLoop Application Logic

Design | Crash: Acceptor
gen_server
[misultin]
. erlang:spawn/1

Http Process HTTP Logic

erlang:spawn_link/1


Design | Crash: Acceptor
gen_server
[misultin]
'EXIT' message: . erlang:spawn/1
gen_server respawns . gen_tcp:controlling_process/2
a new acceptor . call to gen_server to:
Main gen_server


erlang:spawn_link/1


Design | Crash: HttpProcess
gen_server
[misultin]
. erlang:spawn/1


erlang:spawn_link/1


gen_server
[misultin]
. erlang:spawn/1
1.


erlang:spawn_link/1


gen_server
[misultin]
. erlang:spawn/1
1.


erlang:spawn_link/1

2.


gen_server
[misultin]
. erlang:spawn/1
3. 'DOWN' message:
1.
decrease open
connections counter

erlang:spawn_link/1

2.


Design | Crash: HttpLoop
gen_server
[misultin]
. erlang:spawn/1


erlang:spawn_link/1


Design | Crash: HttpLoop
gen_server
[misultin]
. erlang:spawn/1


'EXIT' message:
HttpProcess sends
HTTP 500 error erlang:spawn_link/1
message to client


Design | Crash: gen_server
gen_server
[misultin]
. erlang:spawn/1


erlang:spawn_link/1


1.
gen_server
[misultin]
. erlang:spawn/1


erlang:spawn_link/1


1. 2.
gen_server
[misultin]
. erlang:spawn/1


erlang:spawn_link/1


1. 2.
gen_server
[misultin]
. erlang:spawn/1
terminate(_,_) -> - erlang:monitor/2: for gen_server count
exit(HttpPid, kill). 3.


erlang:spawn_link/1


1. 2.
gen_server
[misultin]
. erlang:spawn/1
terminate(_,_) -> - erlang:monitor/2: for gen_server count
exit(HttpPid, kill). 3.


erlang:spawn_link/1

4.


Benchmarks | Foreword
‣ No such thing as generic benchmarks: speciﬁc case
[fast application times, loads of connections, small data]

‣ ‘Fast’ is only 1 of the ‘n’ features you want
[stability, features, ease of maintenance, low standard deviation, code usability, ...]

‣ This is no ‘pissing’ contest. *Not* what I wanted to see:

Benchmarks | Test
‣ Not only Erlang

‣ Chosen libraries are all lightweight & dynamic
[compare apple with apples: no Yaws, no Nginx]

‣ Periodically close down the TCP connection

‣ All tests run on a single CPU

‣ No RAM/CPU considerations

Benchmarks | Test
‣ ‘Dynamic’ tests: no “Hello world”

The test basically asks servers to:

• check if a GET variable is set

• if the variable is not set, reply with an XML stating the error:

<http_test><error>no value specified</error></http_test>

• if the variable is set, echo it inside an XML

<http_test><value>MYVALUE</value></http_test>

Benchmarks | Setup
‣ Patched HttPerf
[for higher ﬁle handling]

‣ Virtualized Up-to-date Ubuntu 10.04 LTS, 2CPU, 1.5G Ram
[tuning of /etc/sysctl.conf and /etc/security/limits.conf]

‣ Libraries:

• Misultin 0.7.1 (Erlang R14B02)
• Mochiweb 1.5.2 (Erlang R14B02)
• Cowboy master 420f5ba (Erlang R14B02)
• NodeJS 0.4.7
• Tornadoweb 1.2.1 (Python 2.6.5)

‣ All the libraries have been run with the standard settings. Erlang
was launched with Kernel Polling enabled, and with SMP
disabled so that a single CPU was used by all the libraries.

Comet | Practical issues
HTTP Logic

Http Process

spawn_link/1

HttpLoop

Application Logic

HTTP Logic

Http Process
1. Building Req: {active, once} | gen_tcp:recv/3
2. Spawn HttpLoop, enter socket_loop/3

spawn_link/1

HttpLoop

Application Logic

HTTP Logic

Http Process
Actual TCP
sending
spawn_link/1

Data to be Sent

HttpLoop

Application Logic

HTTP Logic

Http Process
Actual TCP
sending => monitor Socket while in socket_loop?
spawn_link/1

Data to be Sent

HttpLoop

Application Logic

HTTP Logic

Http Process
Actual TCP
spawn_link/1 => get data from Socket while in socket_loop?

Data to be Sent

HttpLoop

Application Logic

HTTP Logic

Http Process
Actual TCP

Data to be Sent CONFLICT:

• Catch Client’s Socket closed event
HttpLoop • Support HTTP pipelining

Application Logic

HTTP Logic

Http Process
Actual TCP

Data to be Sent CONFLICT:

• Catch Client’s Socket closed event
HttpLoop • Support HTTP pipelining
SOLUTION:
Application Logic
handle_http(Req) ->
Req:options([{comet, true}]),
...

Thank you
e: roberto@ostinelli.net
t: @ostinelli

>-|-|(°>

�ݺ�ߣ

Misultin 0.7.1 Presentation

More Related Content

Misultin 0.7.1 Presentation

Editor's Notes