cmetrics: add cmt_expire for expiring metrics.

include/cmetrics/cmetrics.h

@@ -78,5 +78,6 @@ struct cmt *cmt_create();
 void cmt_destroy(struct cmt *cmt);
 int cmt_label_add(struct cmt *cmt, char *key, char *val);
 char *cmt_version();
+void cmt_expire(struct cmt *cmt, uint64_t expiration);
 
 #endif

include/cmetrics/cmt_map.h

@@ -57,6 +57,9 @@ int cmt_map_metric_get_val(struct cmt_opts *opts, struct cmt_map *map,
                            double *out_val);
 void cmt_map_metric_destroy(struct cmt_metric *metric);
 
+int cmt_map_metrics_expire(struct cmt_map *, uint64_t);
+
 void destroy_label_list(struct cfl_list *label_list);
 
+
 #endif

src/cmetrics.c

@@ -29,6 +29,7 @@
 #include <cmetrics/cmt_atomic.h>
 #include <cmetrics/cmt_compat.h>
 #include <cmetrics/cmt_label.h>
+#include <cmetrics/cmt_map.h>
 #include <cmetrics/cmt_version.h>
 
 #include <cfl/cfl_kvlist.h>
@@ -136,6 +137,42 @@ void cmt_destroy(struct cmt *cmt)
     free(cmt);
 }
 
+void cmt_expire(struct cmt *cmt, uint64_t expiration)
+{
+    struct cfl_list *tmp;
+    struct cfl_list *head;
+    struct cmt_counter *c;
+    struct cmt_gauge *g;
+    struct cmt_summary *s;
+    struct cmt_histogram *h;
+    struct cmt_untyped *u;
+
+    cfl_list_foreach_safe(head, tmp, &cmt->counters) {
+        c = cfl_list_entry(head, struct cmt_counter, _head);
+        cmt_map_metrics_expire(c->map, expiration);
+    }
+
+    cfl_list_foreach_safe(head, tmp, &cmt->gauges) {
+        g = cfl_list_entry(head, struct cmt_gauge, _head);
+        cmt_map_metrics_expire(g->map, expiration);
+    }
+
+    cfl_list_foreach_safe(head, tmp, &cmt->summaries) {
+        s = cfl_list_entry(head, struct cmt_summary, _head);
+        cmt_map_metrics_expire(s->map, expiration);
+    }
+
+    cfl_list_foreach_safe(head, tmp, &cmt->histograms) {
+        h = cfl_list_entry(head, struct cmt_histogram, _head);
+        cmt_map_metrics_expire(s->map, expiration);
+    }
+
+    cfl_list_foreach_safe(head, tmp, &cmt->untypeds) {
+        u = cfl_list_entry(head, struct cmt_untyped, _head);
+        cmt_map_metrics_expire(u->map, expiration);
+    }
+}
+
 int cmt_label_add(struct cmt *cmt, char *key, char *val)
 {
     return cmt_labels_add_kv(cmt->static_labels, key, val);

src/cmt_map.c

@@ -316,3 +316,19 @@ void destroy_label_list(struct cfl_list *label_list)
     }
 }
 
+/* This function can be used to expire untouched metrics.
+ */
+int cmt_map_metrics_expire(struct cmt_map *map, uint64_t expiration)
+{
+    struct cfl_list *tmp;
+    struct cfl_list *head;
+    struct cmt_metric *metric;
+
+    cfl_list_foreach_safe(head, tmp, &map->metrics) {
+        metric = cfl_list_entry(head, struct cmt_metric, _head);
+        if (metric->timestamp <= expiration) {
+            cmt_map_metric_destroy(metric);
+        }
+    }
+    return 0;
+}