MEDIUM: promex: switch to using stat_cols_info for global metrics

Now the stat_cols_info array contains all info that prometheus requires,
stop using the promex_global_metrics array that contains redundant infos.

Initial goal was to completely drop the promex_global_metrics array.
However it was deemed no longer relevant as prometheus stats rely on a
custom name that cannot be derived from stat_cols_info[], unless we add
a specific ".promex_name" field or similar to name the stats for
prometheus. This is what was carried over on a first attempt but it proved
to burden stat_cols_info[] array (not only memory wise, it is quite
confusing to see promex in the main codebase, given that prometheus is
shipped as an optional add-on).

The new strategy consists in revamping the promex_global_metrics array
from promex_metric (with all redundant fields for metrics) to a simple
ID<==>IST mapping. If the metric is mapped, then it means promex addon
should advertise it (using the name provided in the mapping). Now for
all the metric retrieval, no longer rely on built-in hardcoded values
but instead leverage the new stat cols API.

The tricky part is the .type association because the general rule doesn't
apply for all metrics as it seems that we stated that some non-counters
oriented metrics (at least from haproxy point of view) had to be presented
as counter metrics. So in this patch we add some special treatment for
those metrics to emulate the old behavior. If that's not relevant in the
future, it may be removed. But this requires to ensure that promex users
will properly cope with that change. At least for now, no change of
behavior should be expected.

diff --git a/addons/promex/service-prometheus.c b/addons/promex/service-prometheus.c
index 0df71a6b0ccb0d76c3c12860f0fdf4c63db29704..376ea39d8288db42bda5c69c104eac6ebd90ffb7 100644 (file)
--- a/addons/promex/service-prometheus.c
+++ b/addons/promex/service-prometheus.c
@@ -97,81 +97,109 @@ struct promex_ctx {
  */
 #define PROMEX_MAX_METRIC_LENGTH 512
 
-/* Global metrics  */
-const struct promex_metric promex_global_metrics[ST_I_INF_MAX] = {
-       //[ST_I_INF_NAME]                           ignored
-       //[ST_I_INF_VERSION],                       ignored
-       //[ST_I_INF_RELEASE_DATE]                   ignored
-       [ST_I_INF_NBTHREAD]                       = { .n = IST("nbthread"),                      .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_NBPROC]                         = { .n = IST("nbproc"),                        .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_PROCESS_NUM]                    = { .n = IST("relative_process_id"),           .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       //[ST_I_INF_PID]                            ignored
-       //[ST_I_INF_UPTIME]                         ignored
-       [ST_I_INF_UPTIME_SEC]                     = { .n = IST("uptime_seconds"),                .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_START_TIME_SEC]                 = { .n = IST("start_time_seconds"),            .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       //[ST_I_INF_MEMMAX_MB]                      ignored
-       [ST_I_INF_MEMMAX_BYTES]                   = { .n = IST("max_memory_bytes"),              .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       //[ST_I_INF_POOL_ALLOC_MB]                  ignored
-       [ST_I_INF_POOL_ALLOC_BYTES]               = { .n = IST("pool_allocated_bytes"),          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       //[ST_I_INF_POOL_USED_MB]                   ignored
-       [ST_I_INF_POOL_USED_BYTES]                = { .n = IST("pool_used_bytes"),               .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_POOL_FAILED]                    = { .n = IST("pool_failures_total"),           .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_ULIMIT_N]                       = { .n = IST("max_fds"),                       .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAXSOCK]                        = { .n = IST("max_sockets"),                   .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAXCONN]                        = { .n = IST("max_connections"),               .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_HARD_MAXCONN]                   = { .n = IST("hard_max_connections"),          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CURR_CONN]                      = { .n = IST("current_connections"),           .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CUM_CONN]                       = { .n = IST("connections_total"),             .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CUM_REQ]                        = { .n = IST("requests_total"),                .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAX_SSL_CONNS]                  = { .n = IST("max_ssl_connections"),           .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CURR_SSL_CONNS]                 = { .n = IST("current_ssl_connections"),       .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CUM_SSL_CONNS]                  = { .n = IST("ssl_connections_total"),         .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAXPIPES]                       = { .n = IST("max_pipes"),                     .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_PIPES_USED]                     = { .n = IST("pipes_used_total"),              .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_PIPES_FREE]                     = { .n = IST("pipes_free_total"),              .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CONN_RATE]                      = { .n = IST("current_connection_rate"),       .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CONN_RATE_LIMIT]                = { .n = IST("limit_connection_rate"),         .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAX_CONN_RATE]                  = { .n = IST("max_connection_rate"),           .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SESS_RATE]                      = { .n = IST("current_session_rate"),          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SESS_RATE_LIMIT]                = { .n = IST("limit_session_rate"),            .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAX_SESS_RATE]                  = { .n = IST("max_session_rate"),              .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_RATE]                       = { .n = IST("current_ssl_rate"),              .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_RATE_LIMIT]                 = { .n = IST("limit_ssl_rate"),                .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAX_SSL_RATE]                   = { .n = IST("max_ssl_rate"),                  .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_FRONTEND_KEY_RATE]          = { .n = IST("current_frontend_ssl_key_rate"), .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_FRONTEND_MAX_KEY_RATE]      = { .n = IST("max_frontend_ssl_key_rate"),     .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_FRONTEND_SESSION_REUSE_PCT] = { .n = IST("frontend_ssl_reuse"),            .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_BACKEND_KEY_RATE]           = { .n = IST("current_backend_ssl_key_rate"),  .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_BACKEND_MAX_KEY_RATE]       = { .n = IST("max_backend_ssl_key_rate"),      .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_CACHE_LOOKUPS]              = { .n = IST("ssl_cache_lookups_total"),       .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_SSL_CACHE_MISSES]               = { .n = IST("ssl_cache_misses_total"),        .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_COMPRESS_BPS_IN]                = { .n = IST("http_comp_bytes_in_total"),      .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_COMPRESS_BPS_OUT]               = { .n = IST("http_comp_bytes_out_total"),     .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_COMPRESS_BPS_RATE_LIM]          = { .n = IST("limit_http_comp"),               .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_ZLIB_MEM_USAGE]                 = { .n = IST("current_zlib_memory"),           .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_MAX_ZLIB_MEM_USAGE]             = { .n = IST("max_zlib_memory"),               .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_TASKS]                          = { .n = IST("current_tasks"),                 .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_RUN_QUEUE]                      = { .n = IST("current_run_queue"),             .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_IDLE_PCT]                       = { .n = IST("idle_time_percent"),             .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_NODE]                           = { .n = IST("node"),                          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_DESCRIPTION]                    = { .n = IST("description"),                   .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_STOPPING]                       = { .n = IST("stopping"),                      .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_JOBS]                           = { .n = IST("jobs"),                          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_UNSTOPPABLE_JOBS]               = { .n = IST("unstoppable_jobs"),              .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_LISTENERS]                      = { .n = IST("listeners"),                     .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_ACTIVE_PEERS]                   = { .n = IST("active_peers"),                  .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_CONNECTED_PEERS]                = { .n = IST("connected_peers"),               .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_DROPPED_LOGS]                   = { .n = IST("dropped_logs_total"),            .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_BUSY_POLLING]                   = { .n = IST("busy_polling_enabled"),          .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_FAILED_RESOLUTIONS]             = { .n = IST("failed_resolutions"),            .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_TOTAL_BYTES_OUT]                = { .n = IST("bytes_out_total"),               .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_TOTAL_SPLICED_BYTES_OUT]        = { .n = IST("spliced_bytes_out_total"),       .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_BYTES_OUT_RATE]                 = { .n = IST("bytes_out_rate"),                .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
-       //[ST_I_INF_DEBUG_COMMANDS_ISSUED]          ignored
-       [ST_I_INF_CUM_LOG_MSGS]                   = { .n = IST("recv_logs_total"),               .type = PROMEX_MT_COUNTER, .flags = PROMEX_FL_INFO_METRIC },
-       [ST_I_INF_BUILD_INFO]                     = { .n = IST("build_info"),                    .type = PROMEX_MT_GAUGE,   .flags = PROMEX_FL_INFO_METRIC },
+/* Global metrics names, only exposed if explicitly set  */
+const struct ist promex_global_metrics[ST_I_INF_MAX] = {
+       [ST_I_INF_NBTHREAD]                       = IST("nbthread"),
+       [ST_I_INF_NBPROC]                         = IST("nbproc"),
+       [ST_I_INF_PROCESS_NUM]                    = IST("relative_process_id"),
+       [ST_I_INF_UPTIME_SEC]                     = IST("uptime_seconds"),
+       [ST_I_INF_START_TIME_SEC]                 = IST("start_time_seconds"),
+       [ST_I_INF_MEMMAX_BYTES]                   = IST("max_memory_bytes"),
+       [ST_I_INF_POOL_ALLOC_BYTES]               = IST("pool_allocated_bytes"),
+       [ST_I_INF_POOL_USED_BYTES]                = IST("pool_used_bytes"),
+       [ST_I_INF_POOL_FAILED]                    = IST("pool_failures_total"),
+       [ST_I_INF_ULIMIT_N]                       = IST("max_fds"),
+       [ST_I_INF_MAXSOCK]                        = IST("max_sockets"),
+       [ST_I_INF_MAXCONN]                        = IST("max_connections"),
+       [ST_I_INF_HARD_MAXCONN]                   = IST("hard_max_connections"),
+       [ST_I_INF_CURR_CONN]                      = IST("current_connections"),
+       [ST_I_INF_CUM_CONN]                       = IST("connections_total"),
+       [ST_I_INF_CUM_REQ]                        = IST("requests_total"),
+       [ST_I_INF_MAX_SSL_CONNS]                  = IST("max_ssl_connections"),
+       [ST_I_INF_CURR_SSL_CONNS]                 = IST("current_ssl_connections"),
+       [ST_I_INF_CUM_SSL_CONNS]                  = IST("ssl_connections_total"),
+       [ST_I_INF_MAXPIPES]                       = IST("max_pipes"),
+       [ST_I_INF_PIPES_USED]                     = IST("pipes_used_total"),
+       [ST_I_INF_PIPES_FREE]                     = IST("pipes_free_total"),
+       [ST_I_INF_CONN_RATE]                      = IST("current_connection_rate"),
+       [ST_I_INF_CONN_RATE_LIMIT]                = IST("limit_connection_rate"),
+       [ST_I_INF_MAX_CONN_RATE]                  = IST("max_connection_rate"),
+       [ST_I_INF_SESS_RATE]                      = IST("current_session_rate"),
+       [ST_I_INF_SESS_RATE_LIMIT]                = IST("limit_session_rate"),
+       [ST_I_INF_MAX_SESS_RATE]                  = IST("max_session_rate"),
+       [ST_I_INF_SSL_RATE]                       = IST("current_ssl_rate"),
+       [ST_I_INF_SSL_RATE_LIMIT]                 = IST("limit_ssl_rate"),
+       [ST_I_INF_MAX_SSL_RATE]                   = IST("max_ssl_rate"),
+       [ST_I_INF_SSL_FRONTEND_KEY_RATE]          = IST("current_frontend_ssl_key_rate"),
+       [ST_I_INF_SSL_FRONTEND_MAX_KEY_RATE]      = IST("max_frontend_ssl_key_rate"),
+       [ST_I_INF_SSL_FRONTEND_SESSION_REUSE_PCT] = IST("frontend_ssl_reuse"),
+       [ST_I_INF_SSL_BACKEND_KEY_RATE]           = IST("current_backend_ssl_key_rate"),
+       [ST_I_INF_SSL_BACKEND_MAX_KEY_RATE]       = IST("max_backend_ssl_key_rate"),
+       [ST_I_INF_SSL_CACHE_LOOKUPS]              = IST("ssl_cache_lookups_total"),
+       [ST_I_INF_SSL_CACHE_MISSES]               = IST("ssl_cache_misses_total"),
+       [ST_I_INF_COMPRESS_BPS_IN]                = IST("http_comp_bytes_in_total"),
+       [ST_I_INF_COMPRESS_BPS_OUT]               = IST("http_comp_bytes_out_total"),
+       [ST_I_INF_COMPRESS_BPS_RATE_LIM]          = IST("limit_http_comp"),
+       [ST_I_INF_ZLIB_MEM_USAGE]                 = IST("current_zlib_memory"),
+       [ST_I_INF_MAX_ZLIB_MEM_USAGE]             = IST("max_zlib_memory"),
+       [ST_I_INF_TASKS]                          = IST("current_tasks"),
+       [ST_I_INF_RUN_QUEUE]                      = IST("current_run_queue"),
+       [ST_I_INF_IDLE_PCT]                       = IST("idle_time_percent"),
+       [ST_I_INF_NODE]                           = IST("node"),
+       [ST_I_INF_DESCRIPTION]                    = IST("description"),
+       [ST_I_INF_STOPPING]                       = IST("stopping"),
+       [ST_I_INF_JOBS]                           = IST("jobs"),
+       [ST_I_INF_UNSTOPPABLE_JOBS]               = IST("unstoppable_jobs"),
+       [ST_I_INF_LISTENERS]                      = IST("listeners"),
+       [ST_I_INF_ACTIVE_PEERS]                   = IST("active_peers"),
+       [ST_I_INF_CONNECTED_PEERS]                = IST("connected_peers"),
+       [ST_I_INF_DROPPED_LOGS]                   = IST("dropped_logs_total"),
+       [ST_I_INF_BUSY_POLLING]                   = IST("busy_polling_enabled"),
+       [ST_I_INF_FAILED_RESOLUTIONS]             = IST("failed_resolutions"),
+       [ST_I_INF_TOTAL_BYTES_OUT]                = IST("bytes_out_total"),
+       [ST_I_INF_TOTAL_SPLICED_BYTES_OUT]        = IST("spliced_bytes_out_total"),
+       [ST_I_INF_BYTES_OUT_RATE]                 = IST("bytes_out_rate"),
+       [ST_I_INF_CUM_LOG_MSGS]                   = IST("recv_logs_total"),
+       [ST_I_INF_BUILD_INFO]                     = IST("build_info"),
 };
 
+static inline enum promex_mt_type promex_global_gettype(int index, enum field_nature nature)
+{
+       enum promex_mt_type type;
+
+       /* general rule that fits most types
+        */
+       type = (nature == FN_COUNTER) ? PROMEX_MT_COUNTER : PROMEX_MT_GAUGE;
+
+       /* historically we used to consider some metrics as counters while haproxy
+        * doesn't consider them as such
+        * FIXME: maybe this is no longer needed
+        */
+       switch (index) {
+               case ST_I_INF_POOL_FAILED:
+               case ST_I_INF_CUM_CONN:
+               case ST_I_INF_CUM_REQ:
+               case ST_I_INF_CUM_SSL_CONNS:
+               case ST_I_INF_PIPES_USED:
+               case ST_I_INF_PIPES_FREE:
+               case ST_I_INF_SSL_CACHE_LOOKUPS:
+               case ST_I_INF_SSL_CACHE_MISSES:
+               case ST_I_INF_COMPRESS_BPS_IN:
+               case ST_I_INF_COMPRESS_BPS_OUT:
+               case ST_I_INF_DROPPED_LOGS:
+               case ST_I_INF_FAILED_RESOLUTIONS:
+               case ST_I_INF_TOTAL_BYTES_OUT:
+               case ST_I_INF_TOTAL_SPLICED_BYTES_OUT:
+               case ST_I_INF_CUM_LOG_MSGS:
+                       type = PROMEX_MT_COUNTER;
+                       break;
+               default:
+                       break;
+       }
+
+       return type;
+}
+
 /* frontend/backend/server fields */
 const struct promex_metric promex_st_metrics[ST_I_PX_MAX] = {
        //[ST_I_PX_PXNAME]               ignored
@@ -569,17 +597,21 @@ static int promex_dump_global_metrics(struct appctx *appctx, struct htx *htx)
 
        for (; ctx->field_num < ST_I_INF_MAX; ctx->field_num++) {
                struct promex_label labels[PROMEX_MAX_LABELS-1] = {};
+               enum promex_mt_type type;
                int lb_idx = 0;
 
-               if (!(promex_global_metrics[ctx->field_num].flags & ctx->flags))
+               if (!isttest(promex_global_metrics[ctx->field_num]))
                        continue;
 
-               name = promex_global_metrics[ctx->field_num].n;
+               name = promex_global_metrics[ctx->field_num];
                desc = ist(stat_cols_info[ctx->field_num].desc);
 
                if (promex_filter_metric(appctx, prefix, name))
                        continue;
 
+               val = stat_line_info[ctx->field_num];
+               type = promex_global_gettype(ctx->field_num, (val.type & FN_MASK));
+
                switch (ctx->field_num) {
                        case ST_I_INF_NODE:
                                labels[lb_idx].name  = ist("node");
@@ -602,7 +634,7 @@ static int promex_dump_global_metrics(struct appctx *appctx, struct htx *htx)
                                break;
 
                        default:
-                               val = stat_line_info[ctx->field_num];
+                               break;
                }
 
                if (global.desc && ((ctx->field_num == ST_I_INF_DESCRIPTION) || (ctx->flags & PROMEX_FL_DESC_LABELS))) {
@@ -612,7 +644,7 @@ static int promex_dump_global_metrics(struct appctx *appctx, struct htx *htx)
                }
 
                if (!promex_dump_ts(appctx, prefix, name, desc,
-                                   promex_global_metrics[ctx->field_num].type,
+                                   type,
                                    &val, labels, &out, max))
                        goto full;