mirror of
http://git.haproxy.org/git/haproxy.git/
synced 2024-12-30 00:22:06 +00:00
126 lines
3.8 KiB
Plaintext
126 lines
3.8 KiB
Plaintext
|
There has been a lot of confusion during the development because of the
|
||
|
|
backends and frontends.
|
||
|
|
|
||
|
|
What we want :
|
||
|
|
|
||
|
|
- being able to still use a listener as it has always been working
|
||
|
|
|
||
|
|
- being able to write a rule stating that we will *change* the backend when we
|
||
|
|
match some pattern. Only one jump is allowed.
|
||
|
|
|
||
|
|
- being able to write a "use_filters_from XXX" line stating that we will ignore
|
||
|
|
any filter in the current listener, and that those from XXX will be borrowed
|
||
|
|
instead. A warning would be welcome for options which will silently get
|
||
|
|
masked. This is used to factor configuration.
|
||
|
|
|
||
|
|
- being able to write a "use_backend_from XXX" line stating that we will ignore
|
||
|
|
any server and timeout config in the current listener, and that those from
|
||
|
|
XXX will be borrowed instead. A warning would be welcome for options which
|
||
|
|
will silently get masked. This is used to factor configuration.
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Example :
|
||
|
|
---------
|
||
|
|
|
||
|
|
| # frontend HTTP/80
|
||
|
|
| listen fe_http 1.1.1.1:80
|
||
|
|
| use_filters_from default_http
|
||
|
|
| use_backend_from appli1
|
||
|
|
|
|
||
|
|
| # frontend HTTPS/443
|
||
|
|
| listen fe_https 1.1.1.1:443
|
||
|
|
| use_filters_from default_https
|
||
|
|
| use_backend_from appli1
|
||
|
|
|
|
||
|
|
| # frontend HTTP/8080
|
||
|
|
| listen fe_http-dev 1.1.1.1:8080
|
||
|
|
| reqadd "X-proto: http"
|
||
|
|
| reqisetbe "^Host: www1" appli1
|
||
|
|
| reqisetbe "^Host: www2" appli2
|
||
|
|
| reqisetbe "^Host: www3" appli-dev
|
||
|
|
| use_backend_from appli1
|
||
|
|
|
|
||
|
|
|
|
||
|
|
| # filters default_http
|
||
|
|
| listen default_http
|
||
|
|
| reqadd "X-proto: http"
|
||
|
|
| reqisetbe "^Host: www1" appli1
|
||
|
|
| reqisetbe "^Host: www2" appli2
|
||
|
|
|
|
||
|
|
| # filters default_https
|
||
|
|
| listen default_https
|
||
|
|
| reqadd "X-proto: https"
|
||
|
|
| reqisetbe "^Host: www1" appli1
|
||
|
|
| reqisetbe "^Host: www2" appli2
|
||
|
|
|
|
||
|
|
|
|
||
|
|
| # backend appli1
|
||
|
|
| listen appli1
|
||
|
|
| reqidel "^X-appli1:.*"
|
||
|
|
| reqadd "Via: appli1"
|
||
|
|
| balance roundrobin
|
||
|
|
| cookie app1
|
||
|
|
| server srv1
|
||
|
|
| server srv2
|
||
|
|
|
|
||
|
|
| # backend appli2
|
||
|
|
| listen appli2
|
||
|
|
| reqidel "^X-appli2:.*"
|
||
|
|
| reqadd "Via: appli2"
|
||
|
|
| balance roundrobin
|
||
|
|
| cookie app2
|
||
|
|
| server srv1
|
||
|
|
| server srv2
|
||
|
|
|
|
||
|
|
| # backend appli-dev
|
||
|
|
| listen appli-dev
|
||
|
|
| reqadd "Via: appli-dev"
|
||
|
|
| use_backend_from appli2
|
||
|
|
|
|
||
|
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Now we clearly see multiple things :
|
||
|
|
------------------------------------
|
||
|
|
|
||
|
|
- a frontend can EITHER have filters OR reference a use_filter
|
||
|
|
|
||
|
|
- a backend can EITHER have servers OR reference a use_backend
|
||
|
|
|
||
|
|
- we want the evaluation to cross TWO levels per request. When a request is
|
||
|
|
being processed, it keeps track of its "frontend" side (where it came
|
||
|
|
from), and of its "backend" side (where the server-side parameters have
|
||
|
|
been found).
|
||
|
|
|
||
|
|
- the use_{filters|backend} have nothing to do with how the request is
|
||
|
|
decomposed.
|
||
|
|
|
||
|
|
|
||
|
|
Conclusion :
|
||
|
|
------------
|
||
|
|
|
||
|
|
- a proxy is always its own frontend. It also has 2 parameters :
|
||
|
|
- "fi_prm" : pointer to the proxy holding the filters (itself by default)
|
||
|
|
- "be_prm" : pointer to the proxy holding the servers (itself by default)
|
||
|
|
|
||
|
|
- a request has a frontend (fe) and a backend (be). By default, the backend
|
||
|
|
is initialized to the frontend. Everything related to the client side is
|
||
|
|
accessed through ->fe. Everything related to the server side is accessed
|
||
|
|
through ->be.
|
||
|
|
|
||
|
|
- request filters are first called from ->fe then ->be. Since only the
|
||
|
|
filters can change ->be, it is possible to iterate the filters on ->be
|
||
|
|
only and stop when ->be does not change anymore.
|
||
|
|
|
||
|
|
- response filters are first called from ->be then ->fe IF (fe != be).
|
||
|
|
|
||
|
|
|
||
|
|
When we parse the configuration, we immediately configure ->fi and ->be for
|
||
|
|
all proxies.
|
||
|
|
|
||
|
|
Upon session creation, s->fe and s->be are initialized to the proxy. Filters
|
||
|
|
are executed via s->fe->fi_prm and s->be->fi_prm. Servers are found in
|
||
|
|
s->be->be_prm.
|
||
|
|
|