log: error code generation support

error code and message are generated at compile time by reading a json
file which contains information of elements for each error code.  This
framework provides error handling and ability to do more cleaner log
messages to users.

error-codes.json file contains error description is below format

{
    "ERR_NAME": {"code": ERR_NUM,
                 "message": {"LOCALE": "ERR_MESSAGE"}}
}

At compile time autogen.sh calls gen-headers.py which produces C
header file libglusterfs/src/gf-error-codes.h.  This header has a
function

const char *_gf_get_message (int code);

which returns respective ERR_MESSAGE for given ERR_NUM.

Change-Id: Ieefbf4c470e19a0175c28942e56cec98a3c94ff0
BUG: 928648
Signed-off-by: Bala.FA <barumuga@redhat.com>
Reviewed-on: http://review.gluster.org/4977
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/gen-headers.py b/gen-headers.py
new file mode 100755
index 00000000000..ef9fa77117c
--- /dev/null
+++ b/gen-headers.py
@@ -0,0 +1,54 @@
+#!/usr/bin/python
+
+import sys
+try:
+    import json
+except ImportError:
+    import simplejson as json
+from string import Template
+
+
+def getLogBook(logFile='error-codes.json'):
+    fp = open(logFile)
+    return json.load(fp)
+
+
+def genCHeader(logBook,
+               infile='gf-error-codes.h.template',
+               outfile='gf-error-codes.h'):
+    fp = open('gf-error-codes.h.template')
+    s = fp.read()
+    fp.close()
+    template = Template(s)
+
+    defineLines = []
+    caseLines = []
+    for name, value in logBook.iteritems():
+        nameDef = "GF_%s" % (name.upper(),)
+        code = value['code']
+        msgNameDef = "%s_MSG" % (nameDef,)
+        msg = value['message']['en']
+
+        defineLines.append("#define %-20s %d" % (nameDef, code))
+        defineLines.append("#define %-20s %s" % (msgNameDef,
+                                                 json.dumps(msg)))
+        caseLines.append("        case %s: return _(%s);" % \
+                             (nameDef, msgNameDef))
+
+    d = {'DEFINES': "\n".join(defineLines),
+         'CASES': "\n".join(caseLines)}
+    #print template.substitute(d)
+
+    fp = open(outfile, 'w')
+    fp.write(template.substitute(d))
+    fp.close()
+
+
+if __name__ == "__main__":
+    try:
+        logBook = getLogBook()
+        genCHeader(logBook)
+        sys.exit(0)
+    except IOError, e:
+        print str(e)
+        sys.exit(-1)