VCL state diagram

gistfile1.txt

                                  .-----------------.
                       .----------| receive request |
                       v          '-----------------'
               .--------------.
               |   vcl_recv   |                     Varnish 3.0 state diagram
   .-----------|--------------|-------------.       Not entierly complete.   
   |           | req          |             |       Misses error/restart and 
   v           '--------------'             v       some internals           
 pass                lookup               pipe 
   |                    |                   |
   |                    v                   v          ____________________
   |           .----------------.    .-------------.   \                   \
   |           |    vcl_hash    |    |  vcl_pipe   |    \  Shuffle data     \
   |           |----------------|    |-------------|---->) between client    )
   |           | req            |    | req | bereq |    /  and server       /
   |           '----------------'    '-------------'   /___________________/
   |                   .-hash
   |                   v                 .-------------.
   |              .---------.            |  vcl_miss   |
   |             ( In cache? )--->No --->|-------------|-------.
   |              '---------'            | req | bereq |       |
   |                .-Yes                '-------------'       |
   |                v                                          |
   |           .--------.                .-------------.       |
   |  .--No <-( HitPass? )               |  vcl_pass   |       |
   |  |        '--------'                |-------------|-------.
   |  |            .-Yes                 | req | bereq |       |
   |  |            v                     '-------------'       |
   |  |   .----------------.                    ^              |
   |  |   | Make anonymous |                    |              v
   '--|-->|     object     |--------------------'   .--------------------.
      |   '----------------'      .-----------------| Fetch from backend |
      |                           v                 '--------------------'
      |               .----------------------.
      |               |      vcl_fetch       |
      v               |----------------------|-----------.
.-----------.         | req | bereq | beresp |           v
|  vcl_hit  |         '----------------------'     hit_for_pass
|-----------|                     *                      *
| req | obj |             .----deliver          .----------------.
'-----------'             |---------------------| hitpass = true |
      |                   v                     '----------------'
      |       .-----------------------.             .-----------.
      |       |      vcl_deliver      |             | vcl_error |
      '------>|-----------------------|<------------|-----------|
              | req | resp | obj.hits |             | obj | req |
              '-----------------------'             '-----------'
                          |          .---------------.
                          '--------->| send response |
                                     '---------------'