|
|
@@ -4,7 +4,38 @@ Internals
|
|
|
Architecture
|
|
|
------------
|
|
|
|
|
|
-@todo Describe.
|
|
|
+Cowboy is a lightweight HTTP server.
|
|
|
+
|
|
|
+It is built on top of Ranch. Please see the Ranch guide for more
|
|
|
+informations.
|
|
|
+
|
|
|
+It uses only one process per connection. The process where your
|
|
|
+code runs is the process controlling the socket. Using one process
|
|
|
+instead of two allows for lower memory usage.
|
|
|
+
|
|
|
+It uses binaries. Binaries are more efficient than lists for
|
|
|
+representing strings because they take less memory space. Processing
|
|
|
+performance can vary depending on the operation. Binaries are known
|
|
|
+for generally getting a great boost if the code is compiled natively.
|
|
|
+Please see the HiPE documentation for more details.
|
|
|
+
|
|
|
+Because querying for the current date and time can be expensive,
|
|
|
+Cowboy generates one `Date` header value every second, shares it
|
|
|
+to all other processes, which then simply copy it in the response.
|
|
|
+This allows compliance with HTTP/1.1 with no actual performance loss.
|
|
|
+
|
|
|
+One process for many requests
|
|
|
+-----------------------------
|
|
|
+
|
|
|
+As previously mentioned, Cowboy only use one process per connection.
|
|
|
+Because there can be more than one request per connection with the
|
|
|
+keepalive feature of HTTP/1.1, that means the same process will be
|
|
|
+used to handle many requests.
|
|
|
+
|
|
|
+Because of this, you are expected to make sure your process cleans
|
|
|
+up before terminating the handling of the current request. This may
|
|
|
+include cleaning up the process dictionary, timers, monitoring and
|
|
|
+more.
|
|
|
|
|
|
Lowercase header names
|
|
|
----------------------
|
|
|
@@ -30,8 +61,19 @@ capitalize_hook(Status, Headers, Body, Req) ->
|
|
|
Req2.
|
|
|
```
|
|
|
|
|
|
-Efficiency considerations
|
|
|
--------------------------
|
|
|
+Improving performance
|
|
|
+---------------------
|
|
|
+
|
|
|
+By default the maximum number of active connections is set to a
|
|
|
+generally accepted big enough number. This is meant to prevent having
|
|
|
+too many processes performing potentially heavy work and slowing
|
|
|
+everything else down, or taking up all the memory.
|
|
|
+
|
|
|
+Disabling this feature, by setting the `{max_connections, infinity}`
|
|
|
+protocol option, would give you greater performance when you are
|
|
|
+only processing short-lived requests.
|
|
|
+
|
|
|
+Another option is to define platform-specific socket options that
|
|
|
+are known to improve their efficiency.
|
|
|
|
|
|
-@todo Mention that you need to cleanup in terminate especially if you
|
|
|
-used the process dictionary, started timers, started monitoring...
|
|
|
+Please see the Ranch guide for more information.
|
Loïc Hoguin