view mod_limits/README.markdown @ 4249:64aa1d9d70ac

mod_rest: Catch and log errors in callback promise chain From the code it looks like it should be possible to reply to an error stanza, but it did not. Turns out I was saved by my local developer mode module which throws errors if an attempt is made to create an errror reply to an error stanza. However nothing collects this error from the promise, so all I got was confusion.
author Kim Alvefur <zash@zash.se>
date Sun, 15 Nov 2020 16:25:49 +0100
parents 8de50be756e5
children b935276ab1b4
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---
labels:
- 'Stage-Beta'
summary: 'Connection-level rate limiting'
...

Introduction
============

On some servers, especially public ones, it is desired to make sure that
everyone gets their fair share of system resources (and no more).

mod\_limits allows you to specify traffic bandwidth limits, preventing
any single connection hogging the server's CPU, RAM and bandwidth.

Details
=======

mod\_limits detects when a connection has exceeded its traffic allowance
and temporarily ignores a connection. Due to the way TCP and the OS's
network API works no data is lost, only slowed.

Configuration
=============

Currently mod\_limits is configured per connection type. The possible
connection types are:

-   c2s
-   s2sin
-   s2sout
-   component

The limits are specified like so in the **global** section of your
config (they cannot be per-host):

``` {.lua}
limits = {
  c2s = {
    rate = "3kb/s";
    burst = "2s";
  };
  s2sin = {
    rate = "10kb/s";
    burst = "5s";
  };
}
```

All units are in terms of *bytes*, not *bits*, so that "kb/s" is
interpreted as "kilobytes per second", where a kilobyte is 1000 bytes.

Compatibility
=============

  ----- -------------------
  0.9   Works
  0.8   Doesn't work(\*)
  ----- -------------------

(\*) This module can be made to work in 0.8 if you do two things:

1.  Install
    [util.throttle](http://hg.prosody.im/0.9/raw-file/d46948d3018a/util/throttle.lua)
    into your Prosody source's util/ directory.
2.  If you use libevent apply [this
    patch](http://prosody.im/patches/prosody08-mod-limits-fix.patch) to
    net/server\_event.lua.