mod_log_config: json formatter: Updated manual and some fixes from re…

…view

changes-entries/mod_log_config.txt

@@ -0,0 +1 @@
+  *) mod_log_config: Add support for output log in JSON format [Thomas Meyer]

docs/manual/mod/mod_log_config.xml

@@ -454,6 +454,7 @@
 <description>Sets filename and format of log file</description>
 <syntax>CustomLog  <var>file</var>|<var>pipe</var>|<var>provider</var>
 <var>format</var>|<var>nickname</var>
+[formatter=json[,short]]
 [env=[!]<var>environment-variable</var>|
 expr=<var>expression</var>]</syntax>
 <contextlist><context>server config</context><context>virtual host</context>
@@ -525,7 +526,18 @@ CustomLog "logs/access_log" common
 CustomLog "logs/access_log" "%h %l %u %t \"%r\" %&gt;s %b"
     </highlight>
 
-    <p>The third argument is optional and controls whether or
+    <p>The third argument is optional and controls whether to use a special
+    formatter to create the log records. Currently only the formatter "json" is
+    supported which will create all log records according to RFC8259 and
+    each printed log record will be a JSON object.
+    The optional formatter option "short" make the json formatter output short
+    JSON key names. The JSON key names in short format are directly derived
+    from the format string, i.e. "%s" will result in a JSON of {"s":"304"}.
+    If the "short" option is not specified long JSON key names will be used for
+    better readability in JSON object, e.g. {"statusCode":"304"}
+    </p>
+
+    <p>The last argument is optional and controls whether or
     not to log a particular request. The condition can be the
     presence or absence (in the case of a '<code>env=!<var>name</var></code>'
     clause) of a particular variable in the server

modules/loggers/mod_log_config.c

@@ -1585,7 +1585,7 @@ static config_log_state *open_config_log(server_rec *s, apr_pool_t *p,
     if (cls->log_writer_data == NULL)
         return NULL;
 
-    /* sort log_format_items array, to help json formatter in gruppenwechsel */
+    /* sort log_format_items array, to help json formatter in control break */
     if (cls->log_formatter == ap_json_log_formatter /* sort_log_format_items */ ) {
         /* no valid cls->format given in format string,
            use default_format, if any valid */
@@ -1883,7 +1883,7 @@ static ap_log_formatted_data * ap_json_log_formatter( request_rec *r,
          *
          * as multiple same tags with different arguments can exist,
          * the log_format_item is sorted before, so we can easily check for
-         * gruppenwechsel
+         * control break (https://en.wikipedia.org/wiki/Control_break)
          */
         if(items[i].arg != NULL && strlen(items[i].arg) > 0) {
             /* start sub object */
@@ -1894,7 +1894,7 @@ static ap_log_formatted_data * ap_json_log_formatter( request_rec *r,
                     continue;
                 }
 
-                /* is gruppenwechsel */
+                /* is control break */
                 if(j > i && strcmp(items[j].tag, items[i].tag) != 0) {
                     break;
                 }
@@ -2025,7 +2025,7 @@ static ap_log_formatted_data * ap_json_log_formatter( request_rec *r,
          *
          * as multiple same tags with different arguments can exist,
          * the log_format_item is sorted before, so we can easily check for
-         * gruppenwechsel
+         * control break
          */
         if(items[i].arg != NULL && strlen(items[i].arg) > 0) {
             /* TODO: or allocate once at the begining and use apr_array_clear here? */
@@ -2041,7 +2041,7 @@ static ap_log_formatted_data * ap_json_log_formatter( request_rec *r,
                     continue;
                 }
 
-                /* is gruppenwechsel */
+                /* is control break */
                 if(j > i && strcmp(items[j].tag, items[i].tag) != 0) {
                     break;
                 }