Export host statistics in prometheus text format on /metrics.

diff --git a/hosts_db.c b/hosts_db.c
index 710a0e0..c1dab21 100644 (file)
--- a/hosts_db.c
+++ b/hosts_db.c
@@ -911,19 +911,18 @@ html_hosts(const char *uri, const char *query)
 }
 
 /* ---------------------------------------------------------------------------
- * Format hashtable into HTML.
+ * Get an array of pointers to all the buckets in the hashtable,
+ * or NULL if the hashtable is NULL or empty.
+ * The returned pointer should be free'd by the caller.
  */
-static void
-format_table(struct str *buf, struct hashtable *ht, unsigned int start,
-   const enum sort_dir sort, const int full)
+const struct bucket **
+hashtable_list_buckets(struct hashtable *ht)
 {
    const struct bucket **table;
-   unsigned int i, pos, end;
-   int alt = 0;
+   unsigned int i, pos;
 
    if ((ht == NULL) || (ht->count == 0)) {
-      str_append(buf, "<p>The table is empty.</p>\n");
-      return;
+      return NULL;
    }
 
    /* Fill table with pointers to buckets in hashtable. */
@@ -936,6 +935,51 @@ format_table(struct str *buf, struct hashtable *ht, unsigned int start,
       }
    }
    assert(pos == ht->count);
+   return table;
+}
+
+typedef void (hashtable_foreach_func_t)(const struct bucket *, const void *);
+
+/* ---------------------------------------------------------------------------
+ * Loop over all buckets in the given hashtable, calling the supplied function
+ * with each bucket and the supplied user_data.
+ */
+static void
+hashtable_foreach(struct hashtable *ht,
+   hashtable_foreach_func_t *hashtable_foreach_func,
+   const void *user_data)
+{
+   const struct bucket **table;
+   unsigned int i;
+
+   table = hashtable_list_buckets(ht);
+   if (table == NULL)
+      return;
+
+   for (i = 0; i<ht->count; i++) {
+      const struct bucket *b = table[i];
+      (*hashtable_foreach_func)(b, user_data);
+   }
+   free(table);
+}
+
+/* ---------------------------------------------------------------------------
+ * Format hashtable into HTML.
+ */
+static void
+format_table(struct str *buf, struct hashtable *ht, unsigned int start,
+   const enum sort_dir sort, const int full)
+{
+   const struct bucket **table;
+   unsigned int i, end;
+   int alt = 0;
+
+   table = hashtable_list_buckets(ht);
+
+   if (table == NULL) {
+      str_append(buf, "<p>The table is empty.</p>\n");
+      return;
+   }
 
    if (full) {
       /* full report overrides start and end */
@@ -1171,6 +1215,67 @@ static const unsigned char
    export_tag_host_ver3[] = {'H', 'S', 'T', 0x03},
    export_tag_host_ver4[] = {'H', 'S', 'T', 0x04};
 
+static void text_metrics_counter(struct str *buf, const char *metric, const char *type, const char *help);
+static void text_metrics_format_host(const struct bucket *b, const void *user_data);
+
+/* ---------------------------------------------------------------------------
+ * Web interface: export stats in Prometheus text format on /metrics
+ */
+struct str *
+text_metrics()
+{
+   struct str *buf = str_make();
+
+   text_metrics_counter(buf,
+      "host_bytes_total",
+      "counter",
+      "Total number of network bytes by host and direction.");
+   hashtable_foreach(hosts_db, &text_metrics_format_host, (void *)buf);
+
+   return buf;
+}
+
+static void
+text_metrics_counter(struct str *buf,
+   const char *metric,
+   const char *type,
+   const char *help)
+{
+   str_appendf(buf, "# HELP %s %s\n", metric, help);
+   str_appendf(buf, "# TYPE %s %s\n", metric, type);
+}
+
+static void
+text_metrics_format_host_key(struct str *buf, const struct bucket *b) {
+   const char *ip = addr_to_str(&(b->u.host.addr));
+
+   str_appendf(buf,
+      "host_bytes_total{interface=\"%s\",ip=\"%s\"",
+      title_interfaces, ip);
+
+   if (hosts_db_show_macs)
+      str_appendf(buf, ",mac=\"%x:%x:%x:%x:%x:%x\"",
+         b->u.host.mac_addr[0],
+         b->u.host.mac_addr[1],
+         b->u.host.mac_addr[2],
+         b->u.host.mac_addr[3],
+         b->u.host.mac_addr[4],
+         b->u.host.mac_addr[5]);
+}
+
+static void
+text_metrics_format_host(const struct bucket *b,
+   const void *user_data)
+{
+   struct str *buf = (struct str *)user_data;
+
+   text_metrics_format_host_key(buf, b);
+   str_appendf(buf, ",dir=\"in\"} %qu\n", (qu)b->in);
+
+   text_metrics_format_host_key(buf, b);
+   str_appendf(buf, ",dir=\"out\"} %qu\n", (qu)b->out);
+}
+
 /* ---------------------------------------------------------------------------
  * Load a host's ip_proto table from a file.
  * Returns 0 on failure, 1 on success.

diff --git a/hosts_db.h b/hosts_db.h
index 6abb777..ffb6a03 100644 (file)
--- a/hosts_db.h
+++ b/hosts_db.h
@@ -77,6 +77,7 @@ struct bucket *host_get_ip_proto(struct bucket *host, const uint8_t proto);
 
 /* Web pages. */
 struct str *html_hosts(const char *uri, const char *query);
+struct str *text_metrics();
 
 /* From hosts_sort */
 void qsort_buckets(const struct bucket **a, size_t n,

diff --git a/http.c b/http.c
index a03fdf7..7ba7e47 100644 (file)
--- a/http.c
+++ b/http.c
@@ -42,6 +42,7 @@ static int http_base_len = 0;
 
 static const char mime_type_xml[] = "text/xml";
 static const char mime_type_html[] = "text/html; charset=us-ascii";
+static const char mime_type_text_prometheus[] = "text/plain; version=0.0.4";
 static const char mime_type_css[] = "text/css";
 static const char mime_type_js[] = "text/javascript";
 static const char mime_type_png[] = "image/png";
@@ -688,6 +689,11 @@ static void process_get(struct connection *conn)
         /* hack around Opera caching the XML */
         conn->header_extra = "Pragma: no-cache\r\n";
     }
+    else if (str_starts_with(safe_url, "/metrics")) {
+        struct str *buf = text_metrics();
+        str_extract(buf, &(conn->reply_length), &(conn->reply));
+        conn->mime_type = mime_type_text_prometheus;
+    }
     else if (strcmp(safe_url, "/style.css") == 0)
         static_style_css(conn);
     else if (strcmp(safe_url, "/graph.js") == 0)