--- name: "Perlbal::Manual::Debugging" section: "3pm" platform: "linux" package: "libperlbal-perl" version: "1.80-4" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/Perlbal::Manual::Debugging" --- # Perlbal::Manual::Debugging(3pm) Debugging Perlbal ## 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 \ - • 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.