Provided by: libperlbal-perl_1.80-3_all 
NAME
Perlbal::Manual::Debugging - Debugging Perlbal
VERSION
Perlbal 1.78.
DESCRIPTION
Perlbal has two ways of debugging.
One of them is through a management console; the other is through debugging messages.
Debugging in a console
You'll need to set up a management service and use it to dump all the information you
require.
The comprehensive documentation on this process can be found at
Perlbal::Manual::Management.
Debugging messages
You can control the ammount of debugging messages Perlbal dumps by setting the environment
variable "PERLBAL_DEBUG" to a value between 0 and 4:
PERLBAL_DEBUG = 0 # no debug
PERLBAL_DEBUG = 4 # debug everything
Debug level 1
You can activate basic debug by setting "PERLBAL_DEBUG" to 1:
PERLBAL_DEBUG = 1
The following debugging messages are turned on:
• When a connection to a backend is closed, Perlbal::BackendHTTP prints "Backend $self
is done; closing..."
• When a connection to a backend is killed, Perlbal::ClientProxy prints "Client ($self)
closing backend ($backend)"
• When an HTTP request fails to be parsed, Perlbal::HTTPHeaders prints "HTTP parse
failure: $reason"
• When the connection is promoted to SSL, Perlbal::TCPListener prints " .. socket
upgraded to SSL!"
Debug level 2
By setting the debug level to 2 you'll get all the messages from level 1.
PERLBAL_DEBUG = 2
You will also get a few others:
• When a connection to a backend is opened and ready to be written to,
Perlbal::BackendHTTP prints "Backend $self is writeable!"
• When a response is about to be handled, Perlbal::BackendHTTP prints "BackendHTTP:
handle_response"
• When a backend is ready to be read from, Perlbal::BackendHTTP prints "Backend $self is
readable!"
• When there's an error with the connection to the backend, Perlbal::BackendHTTP prints
"BACKEND event_err"
• Whenever we're determining if we should be sending keep-alive header information back
to the client, Perlbal::ClientHTTPBase prints "ClientHTTPBase::setup_keepalive($self)"
• Whenever the client is ready for more of its file, Perlbal::ClientHTTPBase prints
"REPROXY SSL done"
• Right after we've read a chunk of a file and when a reproxy request is about to be
sent, Perlbal::ClientHTTPBase prints "REPROXY Sent: $sent"
• When we've written all data in the queue (and are about to stop waiting for write
notifications), Perlbal::ClientHTTPBase prints "All writing done to $self"
• Whenever a client proxy is about to be closed, Perlbal::ClientProxy prints
"Perlbal::ClientProxy closed", followed by a possible "again" and a possible "saying
$reason"
• When a client has disconnected, Perlbal::ClientProxy prints
"ClientProxy::client_disconnected"
• When a backend requests a client of a high priority request and the client is
available, "Service" in Perlbal prints "Got from fast queue, in front of $backlog
others"
• When a backend requests a client of a normal priority request and the client is
available, "Service" in Perlbal prints "Backend requesting client, got PRIORITY =
$cp-"{fd}.>
• When a backend requests a client of a low priority request and the client is
available, "Service" in Perlbal prints "Backend requesting client, got low priority =
$cp-"{fd}.>
• When header are being read, Perlbal::Socket prints
"Perlbal::Socket::read_headers($self) is_res=$is_res"
Debug level 3
PERLBAL_DEBUG = 3
By setting the debug level to 3 you'll get all the messages from level 1 and 2 plus the
following:
• Right before response headers are written to the client, Perlbal::BackendHTTP prints "
writing response headers to client"
• As we're writing to the client, Perlbal::BackendHTTP prints " content_length=VALUE"
and " remain=VALUE", where the values are "undef" if they are not defined
• If we're done writing to the client, Perlbal::BackendHTTP prints " done. detaching."
• Whenever we're determining if we should be sending keep-alive header information back
to the client, Perlbal::ClientHTTPBase prints " service's persist_client =
$persist_client"
• While determining if we should be sending keep-alive header information back to the
client, if we were sent "content-length" or it's a head request, as we're doing a keep
alive Perlbal::ClientHTTPBase prints " doing keep-alive to client"
• If we're not sending keep-alive header information back ot the client,
Perlbal::ClientHTTPBase prints " doing connection: close"
• Right after we've finished sending all of the results to the user,
Perlbal::ClientProxy prints "ClientProxy::backend_finished"
• When we've sent a response to a user fully and we need to reset state,
Perlbal::ClientProxy prints "ClientProxy::http_response_sent -- resetting state"
• When we're writing a response to a client, Perlbal::ClientProxy prints
"ClientProxy::event_write"
• After writing a response to a client, if it is still connected and we're triggering
trigger our backend to keep reading, Perlbal::ClientProxy prints " unstalling
backend"
• When reading a request, Perlbal::ClientProxy prints "ClientProxy::event_read"
• When reading a request and just before we read the headers, Perlbal::ClientProxy
prints " no headers. reading."
• When reading a request, if we're not buffering to disk or we're no longer reading, as
we disable reads, Perlbal::ClientProxy prints " disabling reads."
• As we're reading, Perlbal::ClientProxy prints " reading $read_size bytes (VALUE bytes
remain)", where "VALUE bytes remain" can be <undef>
• After each read, Perlbal::ClientProxy prints " read $len bytes"
• After we finished reading the request, Perlbal::ClientProxy prints " done_reading =
$done_reading, backend = BACKEND", where "BACKEND" can be "undef"
• When we send the headers to the backend and it responds before we're done reading from
the client, further reads from the client are discarded; in this situation
Perlbal::ClientProxy prints " already responded.". If the client continues to send
data, Perlbal::ClientProxy prints " already responded [2]." and then gives up on
reading
• After reading, and having a backend available where we can write to, just before we
do, Perlbal::ClientProxy prints " got a backend. sending write to it."
• After reading, if there's no backend available, Perlbal::ClientProxy prints " no
backend. read_ahead = $self-"{read_ahead}.>
• If we know we've already started spooling a file to disk and we're about to continue
doing so, Perlbal::ClientProxy prints " bureason = $self-"{bureason}>
• If a backend wasn't available and we're about to request one, Perlbal::ClientProxy
prints " finally requesting a backend"
• When we're trying to read headers and the client has disconnected, Perlbal::Socket
prints " client disconnected"
• If we need to remove a trailing "\r\n" from the headers, Perlbal::Socket prints "
throwing away leading \r\n"
• If we've read a packet with headers and by the end of it we can't find the end of
them, Perlbal::Socket prints " can't find end of headers"
• Once we've read some headers, Perlbal::Socket prints " pre-parsed headers: [$hstr]"
• After reading headers, if there's additional content that we've read, we push it back;
when we do so, Perlbal::Socket prints " pushing back $len bytes after header"
• If we got bogus headers, and right before we close the connection due to a parsing
failure, Perlbal::Socket prints " bogus headers"
• If we got valid headers, Perlbal::Socket prints " got valid headers"
• If we're reading buffered data from a client, Perlbal::Socket prints "draining readbuf
from $self to $dest: [$$bref]"
Debug level 4
By setting the debug level to 4 you get all the messages from levels 1 to 3.
Plus, "write" is redefined so that whenever "write" is called it first prints
"write($self, <$clen>"$content") from ($pkg, $filename, $line)".
PERLBAL_DEBUG = 4
SEE ALSO
Perlbal::Manual::Configuration, Perlbal::Manual::Management.