digraph G
{
    rankdir = LR
    
    node
    [
        fontname    = "Inconsolata"
        fontsize    = 22
        shape       = record
        style       = rounded
    ]

    edge
    [
        fontname    = "Inconsolata"
        fontsize    = 20
        arrowhead   = vee
        arrowtail   = vee
    ]

    "user\nagents"      -> "web\nserver"    [label="HTTP",dir=both]
    "web\nserver"       -> "PSGI\nhandler"  [label="CGI, mod_perl,\nFastCGI, HTTP",dir=both]
    "PSGI\nhandler"     -> "web\nframework" [label="PSGI",dir=both,fontcolor=blue,fontsize=30]
    "web\nframework"    -> "your\napp"      [label="???",dir=both]

    "web\nframework" [style="rounded,filled",fillcolor="#FFFF88"]

    subgraph cluster_devops {
        fontname    = "Inconsolata"
        fontsize    = 30
        label       = "DevOps"

        "web\nserver"
        "PSGI\nhandler"
    }
}