Parsing a Postgres Startup Message

Help!
1

I am trying to parse the Postgres Startup message. According to the docs, the startup message is thus:

StartupMessage (F)

Int32

Length of message contents in bytes, including self.

Int32(196608)

The protocol version number. The most significant 16 bits are the major version number (3 for the protocol described here). The least significant 16 bits are the minor version number (0 for the protocol described here).

The protocol version number is followed by one or more pairs of parameter name and value strings. A zero byte is required as a terminator after the last name/value pair. Parameters can appear in any order. user is required, others are optional…

Accordingly the message looks like this:
user\0actualusername\0database\0actualdatabase\0\0
(see Selecting backend based on jdbc string connection - #4 by lukastribus)

Here’s is my attempt:

global
        log /dev/log    local0 
        #log /dev/log    local1 debug
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin expose-fd listeners
        stats timeout 30s
        user haproxy
        group haproxy
        daemon

        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private

        # See: https://ssl-config.mozilla.org/#server=haproxy&server-version=2.0.3&config=intermediate
        ssl-default-bind-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
        ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
        ssl-default-bind-options ssl-min-ver TLSv1.2 no-tls-tickets

defaults
        log     global
        mode    http
        mode    tcp
        option  httplog
        option  dontlognull
        timeout connect 5000
        timeout client  50000
        timeout server  50000
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 503 /etc/haproxy/errors/503.http
        errorfile 504 /etc/haproxy/errors/504.http

#---------------------------------------------------------------------
# statistics
#---------------------------------------------------------------------
# Host HA-Proxy's web stats on Port 7000.

listen HAProxy-Statistics 
        bind *:7000
        mode http
        option httplog
        stats enable
        stats uri /haproxy?stats
        stats refresh 20s
        stats realm PSQL Haproxy\ Statistics  # Title text for popup window
        stats show-node
        stats show-legends
        stats show-desc PSQL load balancer stats (master)
        stats auth pgadmin:pgsecret
  
listen  pg_ingress
        #mode   tcp
        bind    *:5000
        option tcplog           # enable addvanced logging
        # hex convert tsdbrw
        acl check-rw req.payload(0,0),hex -m sub 757365720074736462727700
        use_backend pg_readwrite if check-rw
        default_backend pg_readonly
       

backend pg_readwrite
        #mode http
        option httpchk
        http-check expect status 200
        default-server inter 3s fall 3 rise 3 on-marked-down shutdown-sessions
        server tstshd01 172.31.68.147:6432 check port 8008
        server tstshd02 172.31.69.227:6432 check port 8008

backend pg_readonly
        #mode http
        balance leastconn
        default-server inter 3s fall 3 rise 3 on-marked-down shutdown-sessions
        server tstshd01 172.31.68.147:6432
        server tstshd02 172.31.69.227:6432
# end

I simply cant get that acl to resolve to true! Any advice would be greatly appreciated.
Much Thanks,
phil

2

Here’s the dump of the message:

Jun  2 21:14:40 ip-172-31-77-193 haproxy[9031]: #0110x000000: 00 00 00 4c 00 03 00 00   75 73 65 72 00 74 73 64   |...L....user.tsd|
Jun  2 21:14:40 ip-172-31-77-193 haproxy[9031]: #0110x000010: 62 00 64 61 74 61 62 61   73 65 00 74 73 64 62 00   |b.database.tsdb.|
Jun  2 21:14:40 ip-172-31-77-193 haproxy[9031]: #0110x000020: 61 70 70 6c 69 63 61 74   69 6f 6e 5f 6e 61 6d 65   |application_name|
Jun  2 21:14:40 ip-172-31-77-193 haproxy[9031]: #0110x000030: 00 70 73 71 6c 00 63 6c   69 65 6e 74 5f 65 6e 63   |.psql.client_enc|
Jun  2 21:14:40 ip-172-31-77-193 haproxy[9031]: #0110x000040: 6f 64 69 6e 67 00 55 54   46 38 00 00               |oding.UTF8..|
3

This is pretty much what I’ve seen in all the examples. Anyone have an idea why this is not evaluating?