offload event sending

src/server.c

@@ -7,6 +7,7 @@
 #include <signal.h>
 #include <time.h>
 #include <assert.h>
+#include <pthread.h>
 
 #include <json-c/json.h>
 
@@ -17,11 +18,17 @@
 #include "elasticsearch.h"
 
 
-#define BUFF_MAX 5
-
-/*defined here as they are used in conjunction with the shutdown signal handler*/
+/*setting running to 0 will break main loops, exiting the program*/
 int running = 1;
+/*socket listener for udp syslog messages*/
 int sock_fd;
+/*buffer flush thread*/
+pthread_t bufwatch;
+/*lock protecting the buffer*/
+pthread_mutex_t buflock;
+/*occasionally we lookup the time and cache it*/
+time_t cur_t = {0};
+struct tm cur_time = {0};
 
 
 void sig_handler(int signum) {
@@ -32,8 +39,79 @@ void sig_handler(int signum) {
 }
 
 
-time_t cur_t = {0};
-struct tm cur_time = {0};
+void clear_buffer() {
+    char header[72];
+    sprintf(header, "{\"index\": {\"_index\": \"firewall-%04d.%02d.%02d\", \"_type\": \"event\"}}\n",
+            cur_time.tm_year + 1900,
+            cur_time.tm_mon + 1,
+            cur_time.tm_mday);
+
+    // Calculate how large the payload will be
+    int header_size = strlen(header);
+    int num_messages = buff_count();
+    if(num_messages == 0) return;
+    char* messages[num_messages];
+    int message_size = 0;
+    for(int i=0; i<num_messages; i++) {
+        messages[i] = buff_pop();
+        message_size += strlen(messages[i]) + header_size + 1; // 1 newline
+    }
+
+    // Allocate and build the message
+    char* message = calloc(1, message_size + 1);
+    for(int i=0; i<num_messages; i++) {
+        strcat(message, header);
+        strcat(message, messages[i]);
+        strcat(message, "\n");
+        free(messages[i]);
+    }
+
+    // Send it
+    if(put_events(message, "http://192.168.1.120:8298") == 0) {
+        printf("Pushed %d messages\n", num_messages);
+    } else {
+        printf("Failed to post messages!\n");
+    }
+    free(message);
+}
+
+
+void* buffer_watch() {
+    /*flush the buffer when larger than 10 messages or older than 5 seconds*/
+    time_t last_flush = time(NULL);
+    time_t now = last_flush;
+
+    while(running) {
+        usleep(100 * 1000);
+        pthread_mutex_lock(&buflock);  // TODO lock only while clearing the buffer
+        now = time(NULL);
+        if(buff_count() >= 10 || now - last_flush > 5) {
+            printf("\n");
+            clear_buffer();
+            last_flush = now;
+        }
+        pthread_mutex_unlock(&buflock);
+    }
+    return NULL;
+}
+
+
+void start_bufwatch() {
+    if (pthread_mutex_init(&buflock, NULL) != 0) {
+        printf("\n mutex init failed\n");
+        exit(1);
+    }
+    if(pthread_create(&bufwatch, NULL, buffer_watch, NULL) != 0) {
+        printf("Could not create thread\n");
+        exit(1);
+    }
+}
+
+
+void bufwatch_cleanup() {
+    pthread_join(bufwatch, NULL);
+    pthread_mutex_destroy(&buflock);
+}
 
 
 int handle_message(char* msg) {
@@ -88,7 +166,11 @@ int handle_message(char* msg) {
             pfdata_to_json(&fwdata, jobj);
             const char* json_msg = json_object_to_json_string(jobj);
             // printf("%s\n", json_msg);
-            buff_push(strdup(json_msg));  // Copy message to heap and push to buffer
+            {
+                pthread_mutex_lock(&buflock);
+                buff_push(strdup(json_msg));  // Copy message to heap and push to buffer
+                pthread_mutex_unlock(&buflock);
+            }
             json_object_put(jobj);
         }
     }
@@ -96,42 +178,6 @@ int handle_message(char* msg) {
 }
 
 
-void clear_buffer() {
-    char header[72];
-    sprintf(header, "{\"index\": {\"_index\": \"firewall-%04d.%02d.%02d\", \"_type\": \"event\"}}\n",
-            cur_time.tm_year + 1900,
-            cur_time.tm_mon + 1,
-            cur_time.tm_mday);
-
-    // Calculate how large the payload will be
-    int header_size = strlen(header);
-    int num_messages = buff_count();
-    char* messages[num_messages];
-    int message_size = 0;
-    for(int i=0; i<num_messages; i++) {
-        messages[i] = buff_pop();
-        message_size += strlen(messages[i]) + header_size + 1; // 1 newline
-    }
-
-    // Allocate and build the message
-    char* message = calloc(1, message_size + 1);
-    for(int i=0; i<num_messages; i++) {
-        strcat(message, header);
-        strcat(message, messages[i]);
-        strcat(message, "\n");
-        free(messages[i]);
-    }
-
-    // Send it
-    if(put_events(message, "http://192.168.1.120:8298") == 0) {
-        printf("Pushed %d messages\n", num_messages);
-    } else {
-        printf("Failed to post messages!\n");
-    }
-    free(message);
-}
-
-
 /*UDP server bits mostly lifted from https://cs.nyu.edu/~mwalfish/classes/16sp/classnotes/handout01.pdf*/
 int run_server(int port) {
     geo_init();
@@ -155,6 +201,8 @@ int run_server(int port) {
     if (bind(sock_fd, (struct sockaddr*)&my_addr, sizeof(struct sockaddr_in)) < 0)
         panic("bind failed");
 
+    start_bufwatch();
+
     socklen_t addrlen = sizeof(struct sockaddr_in);
     char msg[4096];
     while (running) {
@@ -181,12 +229,9 @@ int run_server(int port) {
 
         printf(".");
         fflush(stdout);
-        if(buff_count() >= BUFF_MAX) {
-            printf("\n");
-            clear_buffer();
-        }
     }
 
+    bufwatch_cleanup();
     buff_freeall();
     geo_close();
     return 1;