Re: Rsyslog stdout and stderr

[Howard Chu <hyc@symas.com>]

Abdelkader Chelouah wrote:
> Hi,
> 
> slapd 2.4.44
> 
> OpenLDAP instance configure as a proxy (back-ldap)
> 
> 
> From time to time, bind operations can take more than 5 sec. These latencies do not seem to come from a CPU or memory problem. I'm trying to see if the network
> can be the root cause of the issue. To debug the fonction ldap_sasl_bind (libraries/libldap/sasl.c), I activated trace loglevel (logs are manage by rsyslog). In
> the definition of ldap_sasl_bind, there is
> 
> Debug( LDAP_DEBUG_TRACE, "ldap_sasl_bind\n", 0, 0, 0 );
> 
> A least the message "ldap_sasl_bind" should appear in logs, which is not the case. Actually, Debug (which is first defined in include/ldap_log.h) is redefined
> in libraries/libldap/ldap-int.h
> 
> ...
> 
> #include "ldap_log.h"
> 
> #undef Debug
> 
> #ifdef LDAP_DEBUG
> 
> #define DebugTest( level ) \
>         ( ldap_debug & level )
> 
> #define Debug( level, fmt, arg1, arg2, arg3 ) \
>         do { if ( ldap_debug & level ) \
>         ldap_log_printf( NULL, (level), (fmt), (arg1), (arg2), (arg3) ); \
>         } while ( 0 )
> 
> #define LDAP_Debug( subsystem, level, fmt, arg1, arg2, arg3 )\
>         ldap_log_printf( NULL, (level), (fmt), (arg1), (arg2), (arg3) )
> configure
> #else
> 
> #define DebugTest( level )                                    (0 == 1)
> #define Debug( level, fmt, arg1, arg2, arg3 )                 ((void)0)
> #define LDAP_Debug( subsystem, level, fmt, arg1, arg2, arg3 ) ((void)0)
> 
> #endif /* LDAP_DEBUG */
> 
> ...
> 
> A a result, the message is send to standard output. By using rsyslog, it is not possible to catch any message inside ldap_sasl_bind.
> 
> 
> How to get stdout and stderr messages and still use rsyslog to manage openldap logs ?

syslog is not fast enough to handle the debug traffic.

You could use ber_set_option() to override the log output functions, and have them write
messages both to rsyslog and stderr. But using syslog on every debug message will slow
things down more than 10x.

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/