WIP: add QH command to access the query handler via livestatus

this PR adds access to the query handler via livestatus. Since livestatus is
commonly used it would be nice to subscribe to events via livestatus too.
So we simply pass through query handler commands and therefor allow things like:

  echo "QH help" | nc -U tmp/run/live

or

  echo "QH @nerd subscribe servicechecks" | nc -U tmp/run/live

TODO:
  - It is not yet interactive, so you send a command once and will get the results.
  - implement proper shutdown

Signed-off-by: Sven Nierlein <sven@nierlein.de>

Author: sni

src/Store.cc

@@ -113,7 +113,7 @@ void Store::registerDowntime(nebstruct_downtime_data *d)
     _table_downtimes.addDowntime(d);
 }
 
-bool Store::answerRequest(InputBuffer *input, OutputBuffer *output)
+bool Store::answerRequest(InputBuffer *input, OutputBuffer *output, int fd)
 {
     output->reset();
     int r = input->readRequest();
@@ -135,6 +135,10 @@ bool Store::answerRequest(InputBuffer *input, OutputBuffer *output)
         answerCommandRequest(lstrip((char *)line + 8), output);
         output->setDoKeepalive(true);
     }
+    else if (!strncmp(line, "QH ", 3)) {
+        output->setDoKeepalive(true);
+        answerQueryHandlerRequest(lstrip((char *)line + 3), output, fd);
+    }
     else if (!strncmp(line, "LOGROTATE", 9)) {
         logger(LG_INFO, "Forcing logfile rotation");
         rotate_log_file(time(0));
@@ -171,6 +175,33 @@ void Store::answerCommandRequest(const char *command, OutputBuffer *output)
     return;
 }
 
+void Store::answerQueryHandlerRequest(const char *command, OutputBuffer *output, int fd)
+{
+    int ret, sd;
+    char buf[4096];
+    sd = nsock_unix(qh_socket_path, NSOCK_TCP | NSOCK_CONNECT);
+    if (sd < 0) {
+        logger(LG_INFO, "Failed to connect to query socket '%s': %s: %s", qh_socket_path, nsock_strerror(sd), strerror(errno));
+        return;
+    }
+    ret = nsock_printf_nul(sd, "%s", command);
+    if (ret < 0) {
+        logger(LG_INFO, "failed to submit command by query handler");
+    }
+    output->reset();
+    while(TRUE) {
+        ret = read(sd, buf, 4095);
+        if(ret <= 0)
+            break;
+        buf[ret] = 0;
+        dprintf(fd, "%s", buf);
+    }
+    close(sd);
+    return;
+}
+
+
+
 
 void Store::answerGetRequest(InputBuffer *input, OutputBuffer *output, const char *tablename)
 {

src/Store.h

@@ -69,12 +69,13 @@ class Store
     void registerHostgroup(hostgroup *);
     void registerComment(nebstruct_comment_data *);
     void registerDowntime(nebstruct_downtime_data *);
-    bool answerRequest(InputBuffer *, OutputBuffer *);
+    bool answerRequest(InputBuffer *, OutputBuffer *, int);
 
 private:
     Table *findTable(string name);
     void answerGetRequest(InputBuffer *, OutputBuffer *, const char *);
     void answerCommandRequest(const char *, OutputBuffer *);
+    void answerQueryHandlerRequest(const char *, OutputBuffer *, int);
 };
 
 #endif // Store_h

src/module.c

@@ -192,7 +192,7 @@ void *client_thread(void *data)
         while (keepalive && !g_should_terminate) {
             if (g_debug_level >= 2 && requestnr > 1)
                 logger(LG_INFO, "Handling request %d on same connection", requestnr);
-            keepalive = store_answer_request(input_buffer, output_buffer);
+            keepalive = store_answer_request(input_buffer, output_buffer, cc);
             flush_output_buffer(output_buffer, cc);
             g_counters[COUNTER_REQUESTS]++;
             requestnr ++;

src/store.cc

@@ -75,9 +75,9 @@ void store_register_downtime(nebstruct_downtime_data *d)
     g_store->registerDowntime(d);
 }
 
-int store_answer_request(void *ib, void *ob)
+int store_answer_request(void *ib, void *ob, int fd)
 {
-    return g_store->answerRequest((InputBuffer *)ib, (OutputBuffer *)ob);
+    return g_store->answerRequest((InputBuffer *)ib, (OutputBuffer *)ob, fd);
 }
 
 void *create_outputbuffer(int *termination_flag)

src/store.h

@@ -36,7 +36,7 @@ extern "C"
     void store_deinit();
     void store_register_comment(nebstruct_comment_data *);
     void store_register_downtime(nebstruct_downtime_data *);
-    int  store_answer_request(void *input_buffer, void *output_buffer);
+    int  store_answer_request(void *input_buffer, void *output_buffer, int fd);
     void *create_outputbuffer(int *termination_flag);
     void flush_output_buffer(void *ob, int fd);
     void delete_outputbuffer(void *);