++ed by:
CHENGANG KIO KANISHKA MARKSTOS

4 PAUSE user(s)
1 non-PAUSE user(s).

Alan Kasindorf
and 1 contributors

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.