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App::Foca::Server - Foca server
Foca is an application (a HTTP server using HTTP::Daemon) that allows
the execution of pre-defined commands via, obviously, HTTP.
Well, lets suppose you have a log parser on all your servers and you are
in need to parse all of them, the common way would be to ssh to each
host (can be as simple as ssh'ing to each host or using a multiplex
tool) and execute your parser, but what if your SSH keys or the keys of
a user are not there? It will be a heck of pain to enter your password
hundred of times or lets imagine you want to parse your logs via some
automation (like doing it from an IRC bot or tied to your monitoring
solution).. then the problem comes more complex with SSH and private
keys. With Foca you don't need to worry about those things, the command
will get executed and the output will be returned as a HTTP response.
All commands that Foca knows about it are listed in a YAML file. Foca
uses a default timeout value for all commands but with this YAML file
you can give a specific timeout to a specific command. All commands are
executed with IPC (open3).
Now the question is.. is Foca secure? Well it depends on you. Depends if
you run it as non-root user and the commands you define. Foca will try
to do things to protect, for example it will reject all requests that
have pipes (|), I/O redirection (>, <, <<, >>), additionally the HTTP
request will be validated before it gets executed via the call of
"validate_request()" (App::Foca returns true all the time so if you want
to add extra functionality please create a subclass and re-define the
my $server = App::Foca::Server->new(
port => $port,
commands_file => $commands,
commands_timeout => $timeout,
debug => $debug);
- /some/path/over/there/bin
cmd: '/bin/df {%foca_args%} | tail -n1'
cmd: '/usr/bin/uptime'
cmd: '/bin/true'
The way the example commands file work is: First it will look if there
is a *commands_dir* key, this key should have a list of directories
(that means it should be an array reference), Foca will look for all
executables inside the given directories and add them into memory.
Second, it will look for the *commands* key, this one should be a hash
where each key is the name of the command and it should have at least a
*cmd* key which value should be the *real* command to execute.
Please note that when you use the *commands_dir*, Foca will use the
basename of each executable as the name of the command so if you have
/usr/local/foo, the foca command will be *foo* while the command it will
execute will be */usr/local/foo*.
Also, you can override commands found in *commands_dir* via *commands*,
so going back to our /usr/local/foo example, you can have this
executable in your /usr/local directory but also have a *foo* command
defined in *commands*, the one that is defined in *commands* will be the
one that will be used by Foca.
There are two ways to update the list of commands once the server
started: One is by obviously restarting it and the other one is via
localhost send a HTTP request to localhost:yourport/reload.
YAML file with the supported commands.
Hash reference with a list of supported commands. Basically the
content of "commands_file".
Where to listen for requests?
Global timeout for all commands. Default to 1min (60 seconds).
Temporary directory, for cache.
Debug/verbose mode, turned off by default.
App::Foca::Server::HTTP object.
For mmap cache (so we can share cache across processes).
Runs the HTTP::Daemon server. it forks on each request.
Prepares a response (HTTP::Response) for the /status request. /status
requests returns some stats about Foca server, such as: number of active
connections, number of closed/zombie connections (user connected and
left the connection open with a process that is no longer needed).
prepare_foca_response($connection, $request)
Prepares a response (HTTP::Response) for a given foca request
build_response($code, $body)
Builds a HTTP response ("HTTP::Response") based on the given HTTP status
code and optionally adds a body.
Returns a "HTTP::Response" so it can be send via the opened connection.
validate_request($command, $request)
re-define this method if you want to add some extra security. By default
all requests are valid at this point.
run_cmd($connection, $name, $cmd, $params)
Runs whatever the command is and sets a timeout to it. If it takes too
long then it will try to kill the process.
Depending on the settings given to the command it will return the STDOUT
or STDERR or even both. The rules are:
1. On success it will look for STDOUT, if nothing is there then it looks
in STDERR. If nothing is foudn in STDERR and STDOUT then an empty string
is returned.
2. On error it will look for STDERR first, if nothing is there then it
looks in STDOUT. If nothing is there then it returns an empty string.
Both STDOUT and STDERR can be returned if the command is defined as
cmd: '/usr/bin/uptime'
capture_all: 'y'
Load the commands YAML file and stores it in memory with Cache::FastMnap
Copyright (c) 2010-2012 Yahoo! Inc. All rights reserved.
This program is free software. You may copy or redistribute it under the
same terms as Perl itself. Please see the LICENSE file included with
this project for the terms of the Artistic License under which this
project is licensed.
Pablo Fischer (