Merge branch '510-prometheus-and-graphite-metrics-are-missing-some-cache-stats' into 'master'

cache: add number of entries to cache.stats()

Closes #510

See merge request !1028

NEWS

@@ -5,6 +5,7 @@ Improvements
 ------------
 - capabilities are no longer constrained when running as root (!1012)
 - cache: add percentage usage to cache.stats() (!1025)
+- cache: add number of cache entries to cache.stats() (!1028)
 - aarch64 support again, as some systems still didn't work (!1033)
 
 Bugfixes

daemon/bindings/cache.c

@@ -81,6 +81,8 @@ static int cache_stats(lua_State *L)
 	add_stat(open);
 	add_stat(close);
 	add_stat(count);
+	cache->stats.count_entries = cache->api->count(cache->db, &cache->stats);
+	add_stat(count_entries);
 	add_stat(clear);
 	add_stat(commit);
 	add_stat(read);

daemon/bindings/cache.rst

@@ -186,7 +186,7 @@ Configuration reference
 
 .. function:: cache.stats()
 
-   Return table with low-level statistics for each internal cache operation.
+   Return table with low-level statistics for internal cache operation and storage.
    This counts each access to cache and does not directly map to individual
    DNS queries or resource records.
    For query-level statistics see :ref:`stats module <mod-stats>`.
@@ -196,23 +196,27 @@ Configuration reference
    .. code-block:: lua
 
        > cache.stats()
-       [read_leq_miss] => 4
-       [write] => 189
-       [read_leq] => 9
-       [read] => 4313
-       [read_miss] => 1143
-       [open] => 0
+       [clear] => 0
        [close] => 0
-       [remove_miss] => 0
        [commit] => 117
-       [match_miss] => 2
-       [match] => 21
        [count] => 2
-       [clear] => 0
+       [count_entries] => 6187
+       [match] => 21
+       [match_miss] => 2
+       [open] => 0
+       [read] => 4313
+       [read_leq] => 9
+       [read_leq_miss] => 4
+       [read_miss] => 1143
        [remove] => 17
+       [remove_miss] => 0
+       [usage_percent] => 15.625
+       [write] => 189
+
 
    Cache operation `read_leq` (*read less or equal*, i.e. range search) was requested 9 times,
    and 4 out of 9 operations were finished with *cache miss*.
+   Cache contains 6187 internal entries which occupy 15.625 % cache size.
 
 
 .. function:: cache.max_ttl([ttl])

daemon/lua/kres-gen.lua

@@ -199,6 +199,7 @@ struct kr_cdb_stats {
 	uint64_t open;
 	uint64_t close;
 	uint64_t count;
+	uint64_t count_entries;
 	uint64_t clear;
 	uint64_t commit;
 	uint64_t read;

lib/cache/cdb_api.h

@@ -18,6 +18,7 @@ struct kr_cdb_stats {
 	uint64_t open;
 	uint64_t close;
 	uint64_t count;
+	uint64_t count_entries;
 	uint64_t clear;
 	uint64_t commit;
 	uint64_t read;