Browser SOA Debugger
Depending on the view of things this is just an enhanced HTTP output formatter for tcpdump streams, or the ultimate debugger for complex HTTP oriented SOA architectures which visualizes the full HTTP interactions in a readable, reproducible way so that you can see what is actually going on in your backend.
To use this thingy on localhost, do something like:
tcpdump -l -i lo -s0 'tcp and (port 80 or port 8983)' -w - | bsoad | bsoad-bdog
This will dump all HTTP and Solr interactions using their respective default ports.
Important is the -w - flag for TCPDump so that the raw binary output is written to stdout.
You can always let TCPDump write into some file and pipe that into bsoad later, of course.
If some errors are happening record the stream originating from tcpdump and store it. This enables you / me to debug bsoad with the same input data. You may use tee for that, like:
tcpdump -l -i lo -s0 'tcp and port 80' -w - | tee /tmp/dump.pcap | bsoad | bsoad-bdog
You can then replay the dump using:
cat /tmp/dump.pcap | bsoad | bsoad-bdog
This project depends on bdog -- to install it execute these commands:
composer.phar install cd src/library/qafoo/bdog npm install git submodule init git submodule update
TCPDump returns the raw TCP packets, which are then parsed and processed by BSOAD.
I first tried to use tools like TShark (Wireshark CLI), but they mess up the HTTP traffic, omit important processing information and do not manage to process all HTTP interactions. So I went this "hard" way.
BSOAD then parses the Ethernet frames, which contain IP headers (IPv4 and IPv6 are supported), which then contain the TCP headers, which contain the actual data.
On top of that BSOAD implements TCP stream handling, which takes care of TCP packet sorting, duplicate detection and so on. The sorted packet data is then passed on to a parser for the data.
The parser is constructed by a parser factory. Currently only a HTTP parser is available together with a parser factory which always only will construct HTTP parsers. But you could add support for other protocols here, together with some magic to detect the current protocol, like Wireshark does, for example.
The HTTP parser the processes the data stream and extracts HTTP interactions (request response tuples) from it. In HTTP 1.1 Connection Keep-Alive scenarios there might be a bunch of them in one connection. BSOAD the converts those in JSON which is echo'd by BSOAD -- by default on STDOUT.
BSOAD additionally returns a simplified log of all interaction on STDERR.
The returned JSON is then piped into bdog using a custom profile for BSOAD. BDog opens a node.js server, connects a browser to it, which then displays the HTTP interactions in a very convenient way.
We release this tool under AGPL v3. Yes, we know what this means.
- There is no proper handling of ongoing TCP interactions. If tcpdump returns packets of an already running TCP interaction, where bsoad does not receive the initial SYN packet it will abort with an error.
- There might still be errors left in TCP stream handling, if you happen to find one, please provide me with a stream dump. They might proove interesting to reproduce, though.
- There might also be problems in the HTTP parser. I am not sure about some of the assumptions in there. Be kind.