10.1 Read logs from a socket

Most of the main utilities are able to write their log files to a Unix Domain socket if configured that way. watchgnupg is a simple listener for such a socket. It ameliorates the output with a time stamp and makes sure that long lines are not interspersed with log output from other utilities. This tool is not available for Windows.

watchgnupg is commonly invoked as

watchgnupg

which is a shorthand for

watchgnupg --force $(gpgconf --list-dirs socketdir)/S.log

To watch GnuPG running with a different home directory, use

watchgnupg --homedir DIR

This starts it on the current terminal for listening on the standard logging socket (this is commonly /var/run/user/UID/gnupg/S.log or if no such user directory hierarchy exists ~/.gnupg/S.log).

watchgnupg understands these options:

--force

Delete an already existing socket file. This option is implicitly used if no socket name has been given on the command line.

--homedir DIR

If no socket name is given on the command line, pass DIR to gpgconf so that the socket for a GnuPG running with DIR has its home directory is used. Note that the environment variable GNUPGHOME is ignored by watchgnupg.

--tcp n

Instead of reading from a local socket, listen for connects on TCP port n. A Unix domain socket can optionally also be given as a second source. This option does not use a default socket name.

--time-only

Do not print the date part of the timestamp.

--verbose

Enable extra informational output.

--version

Print version of the program and exit.

--help

Display a brief help page and exit.

Examples

$ watchgnupg --time-only

This waits for connections on the local socket (e.g. /var/run/user/1234/gnupg/S.log) and shows all log entries. To make this work the option log-file needs to be used with all modules which logs are to be shown. The suggested entry for the configuration files is:

log-file socket://

If the default socket as given above and returned by "echo $(gpgconf –list-dirs socketdir)/S.log" is not desired an arbitrary socket name can be specified, for example socket:///home/foo/bar/mysocket. For debugging purposes it is also possible to do remote logging. Take care if you use this feature because the information is send in the clear over the network. Use this syntax in the conf files:

log-file tcp://192.168.1.1:4711

You may use any port and not just 4711 as shown above; only IP addresses are supported (v4 and v6) and no host names. You need to start watchgnupg with the tcp option. Note that under Windows the registry entry HKCU\Software\GNU\GnuPG:DefaultLogFile can be used to change the default log output from stderr to whatever is given by that entry. However the only useful entry is a TCP name for remote debugging.