log: send current gf_log to syslog conditionally

When compile time option GF_USE_SYSLOG is enabled (which is default),
generated logs are sent to syslog with error code ERR_DEV.

User can opt to use traditional log at run time by creating
/var/log/glusterd/logger.conf file and restarting respective gluster
services.

Change-Id: I9837d0f99da1afc2189d7ecd214c4293ec53715a
BUG: 928648
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://review.gluster.org/5002
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/doc/logging.txt b/doc/logging.txt
new file mode 100644
index 00000000000..d1e568a31ab
--- /dev/null
+++ b/doc/logging.txt
@@ -0,0 +1,65 @@
+
+New logging framework in glusterfs is targeted for end users like
+customers, community members, testers etc.  This aims to bring clear,
+understandable logs called user logs whereas the current logging are
+considered as developer logs.  The new framework brings with following
+features
+
+* Each message is logged with proper well defined error code and each
+  error code has well known error message.
+* A logbook has defined error code and error messages.  It helps to
+  keep track of possible causes and remedies
+* Log are sent to syslog.  The syslog application can be configured to
+  pass them to centralized logging system
+* It brings
+  - Remove repeated log messages
+  - Send alerts to users on certain events
+  - Run a program on events
+  - Call home service on events
+
+
+Log book:
+=========
+A log book is a JSON formatted file error-codes.json located in top
+level of glusterfs source repository.  At compile time, gen-headers.py
+generates libglusterfs/src/gf-error-codes.h using the log book and
+gf-error-codes.h.template file.  libglusterfs/src/gf-error-codes.h
+consists of header definitions and helper functions to get message by
+code for given locale. Currently it has _gf_get_message() function
+returns message for locale 'en'.
+
+New entry to log book is added like
+
+{
+    "IO_ERROR": {"code": 2233,
+                 "message": {"en": "I/O error occurred"}},
+    "SETUP_ERROR": {"code": 2240,
+                 "message": {"en": "Setup error"}},
+}
+
+
+Logging:
+========
+The framework provides two functions
+
+void gf_openlog (const char *ident, int option, int facility);
+void gf_syslog (int error_code, int facility_priority, char *format, ...);
+
+Consumers need to call gf_openlog() prior to gf_syslog() like the way
+traditional syslog function calls.  error_code is mandatory when using
+gf_syslog().  For example,
+
+gf_openlog (NULL, -1, -1);
+gf_syslog (GF_ERR_DEV, LOG_ERR, "error reading configuration file");
+
+The logs are sent in CEE format (http://cee.mitre.org/) to syslog.
+Its targeted to rsyslog syslog server.
+
+This log framework can be disabled either at compile time or run time
+
+- for compile time by passing '--disable-syslog' to ./configure or
+   '--without syslog' to rpmbuild (or)
+- for run time by having a file /var/log/glusterd/logger.conf and
+  restarting gluster services
+
+Currently all gluster logs are sent with error code GF_ERR_DEV.