Perlbal::Manual::Debugging - Debugging Perlbal
Perlbal 1.78.
Perlbal has two ways of debugging.
One of them is through a management console; the other is through debugging messages.
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.
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
PERLBAL_DEBUG = 0 # no debug PERLBAL_DEBUG = 4 # debug everything
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...
Backend $self is done; closing...
When a connection to a backend is killed, Perlbal::ClientProxy prints Client ($self) closing backend ($backend)
Client ($self) closing backend ($backend)
When an HTTP request fails to be parsed, Perlbal::HTTPHeaders prints HTTP parse failure: $reason
HTTP parse failure: $reason
When the connection is promoted to SSL, Perlbal::TCPListener prints .. socket upgraded to SSL!
.. socket upgraded to SSL!
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!
Backend $self is writeable!
When a response is about to be handled, Perlbal::BackendHTTP prints BackendHTTP: handle_response
BackendHTTP: handle_response
When a backend is ready to be read from, Perlbal::BackendHTTP prints Backend $self is readable!
Backend $self is readable!
When there's an error with the connection to the backend, Perlbal::BackendHTTP prints BACKEND event_err
BACKEND event_err
Whenever we're determining if we should be sending keep-alive header information back to the client, Perlbal::ClientHTTPBase prints ClientHTTPBase::setup_keepalive($self)
ClientHTTPBase::setup_keepalive($self)
Whenever the client is ready for more of its file, Perlbal::ClientHTTPBase prints REPROXY SSL done
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
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
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
Perlbal::ClientProxy closed
again
saying $reason
When a client has disconnected, Perlbal::ClientProxy prints ClientProxy::client_disconnected
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
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}.>
Backend requesting client, got PRIORITY = $cp-
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}.>
Backend requesting client, got low priority = $cp-
When header are being read, Perlbal::Socket prints Perlbal::Socket::read_headers($self) is_res=$is_res
Perlbal::Socket::read_headers($self) is_res=$is_res
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
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
content_length=VALUE
remain=VALUE
undef
If we're done writing to the client, Perlbal::BackendHTTP prints done. detaching.
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
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
content-length
doing keep-alive to client
If we're not sending keep-alive header information back ot the client, Perlbal::ClientHTTPBase prints doing connection: close
doing connection: close
Right after we've finished sending all of the results to the user, Perlbal::ClientProxy prints ClientProxy::backend_finished
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
ClientProxy::http_response_sent -- resetting state
When we're writing a response to a client, Perlbal::ClientProxy prints ClientProxy::event_write
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
unstalling backend
When reading a request, Perlbal::ClientProxy prints ClientProxy::event_read
ClientProxy::event_read
When reading a request and just before we read the headers, Perlbal::ClientProxy prints no headers. reading.
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.
disabling reads.
As we're reading, Perlbal::ClientProxy prints reading $read_size bytes (VALUE bytes remain), where VALUE bytes remain can be <undef>
reading $read_size bytes (VALUE bytes remain)
VALUE bytes remain
After each read, Perlbal::ClientProxy prints read $len bytes
read $len bytes
After we finished reading the request, Perlbal::ClientProxy prints done_reading = $done_reading, backend = BACKEND, where BACKEND can be undef
done_reading = $done_reading, backend = BACKEND
BACKEND
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
already responded.
already responded [2].
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.
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}.>
no backend. read_ahead = $self-
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}>
bureason = $self-
If a backend wasn't available and we're about to request one, Perlbal::ClientProxy prints finally requesting a backend
finally requesting a backend
When we're trying to read headers and the client has disconnected, Perlbal::Socket prints client disconnected
client disconnected
If we need to remove a trailing \r\n from the headers, Perlbal::Socket prints throwing away leading \r\n
\r\n
throwing away leading \r\n
If we've read a packet with headers and by the end of it we can't find the end of them, Perlbal::Socket prints can't find end of headers
can't find end of headers
Once we've read some headers, Perlbal::Socket prints pre-parsed headers: [$hstr]
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
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
bogus headers
If we got valid headers, Perlbal::Socket prints got valid headers
got valid headers
If we're reading buffered data from a client, Perlbal::Socket prints draining readbuf from $self to $dest: [$$bref]
draining readbuf from $self to $dest: [$$bref]
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, $line).
write
write($self, <$clen>"$content") from ($pkg, $filename, $line)
PERLBAL_DEBUG = 4
Perlbal::Manual::Configuration, Perlbal::Manual::Management.
To install Perlbal, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Perlbal
CPAN shell
perl -MCPAN -e shell install Perlbal
For more information on module installation, please visit the detailed CPAN module installation guide.