aiohttp.blockdiag

blockdiag {
    orientation = portrait;

    begin[shape=beginpoint, description="on_request_start"];
    redirect[description="on_request_redirect"];
    end[shape=endpoint, description="on_request_end"];
    exception[shape=flowchart.terminator, description="on_request_exception"];

    //acquire_connection[description="Connection acquiring"];

    group header_timeout {
        label = "8. header_timeout";
        color = "#FFFF00";
        shape = line;
        style = dashed;

        headers_received;
        headers_sent;
        chunk_sent[description="on_request_chunk_sent"];
    }

    chunk_received[description="on_response_chunk_received"];

    begin -> begin_acquire_con;
    end_acquire_con -> headers_sent;
    headers_sent -> headers_received;
    headers_sent -> chunk_sent;
    chunk_sent -> chunk_sent [thick];
    chunk_sent -> headers_received;
    headers_received -> chunk_received;
    chunk_received -> chunk_received;
    chunk_received -> end [thick];
    headers_received -> redirect;
    headers_received -> end [thick];
    redirect -> headers_sent;
    chunk_received -> exception;
    chunk_sent -> exception;
    headers_sent -> exception;

    group acquire_con {
        label = "acquire_con (6. timeout)";
        color = "#77FF77";

        begin_acquire_con[shape=beginpoint];
        end_acquire_con[shape=endpoint];
        exception_acquire_con[shape=flowchart.terminator, description="Exception raised"];

        group queued_timeout {
            label = "2. queued_timeout";
            color = "#FF0000";
            shape = line;
            style = dashed;

            queued_start[description="on_connection_queued_start"];
            queued_end[description="on_connection_queued_end"];
        }


        group con_create_timeout {
            label = "3. con_create_timeout";
            color = "#FF0000";
            shape = line;
            style = dashed;
        
            create_start[description="on_connection_create_start"];
            create_end[description="on_connection_create_end"];
            
            //resolve_dns[description="DNS resolving"];

            group sock_connect_timeout {
                label = "5. sock_connect_timeout";
                color = "#FFFF00";
                shape = line;
                style = dashed;

                sock_connect[description="Connection establishment"];
            }

            group resolve_dns {
                label = "resolve_dns (4. timeout)";
                color = "#7777FF";

                begin_resolve_dns[shape=beginpoint];
                end_resolve_dns[shape=endpoint];
                exception_resolve_dns[shape=flowchart.terminator, description="Exception raised"];

                resolve_start[description="on_dns_resolvehost_start"];
                resolve_end[description="on_dns_resolvehost_end"];
                cache_hit[description="on_dns_cache_hit"];
                cache_miss[description="on_dns_cache_miss"];

                begin_resolve_dns -> cache_hit -> end_resolve_dns;
                begin_resolve_dns -> cache_miss -> resolve_start;
                resolve_start -> resolve_end -> end_resolve_dns;
                resolve_start -> exception_resolve_dns;
            }
        }

        reuseconn[description="on_connection_reuseconn"];


        begin_acquire_con -> reuseconn;
        begin_acquire_con -> create_start [thick];
        create_start -> begin_resolve_dns;
        end_resolve_dns -> exception_acquire_con;
        end_resolve_dns -> sock_connect;
        sock_connect -> exception_acquire_con;
        sock_connect -> create_end -> end_acquire_con;
        begin_acquire_con -> queued_start;
        queued_start -> queued_end;
        queued_end -> reuseconn;
        queued_end -> create_start;
        reuseconn -> end_acquire_con;

    }
}