[WIP] feat(proxy-wasm/metrics) histograms support

src/common/ngx_wa_metrics.h

@@ -13,12 +13,14 @@ typedef struct ngx_wa_metrics_s  ngx_wa_metrics_t;
 typedef enum {
     NGX_WA_METRIC_COUNTER,
     NGX_WA_METRIC_GAUGE,
+    NGX_WA_METRIC_HISTOGRAM,
 } ngx_wa_metric_type_e;
 
 
 typedef struct {
-    size_t      slab_size;
-    size_t      max_metric_name_length;
+    size_t                  slab_size;
+    size_t                  max_metric_name_length;
+    size_t                  max_histogram_bins;
 } ngx_wa_metrics_conf_t;
 
 

src/common/proxy_wasm/ngx_proxy_wasm_host.c

@@ -1608,6 +1608,10 @@ ngx_proxy_wasm_hfuncs_define_metric(ngx_wavm_instance_t *instance,
             type = NGX_WA_METRIC_GAUGE;
             break;
 
+        case NGX_PROXY_WASM_METRIC_HISTOGRAM:
+            type = NGX_WA_METRIC_HISTOGRAM;
+            break;
+
         default:
             return ngx_proxy_wasm_result_trap(pwexec, "unknown metric type",
                                               rets,

t/03-proxy_wasm/hfuncs/metrics/400-record_histogram.t

@@ -0,0 +1,193 @@
+# vim:set ft= ts=4 sts=4 sw=4 et fdm=marker:
+
+use strict;
+use lib '.';
+use t::TestWasmX;
+
+skip_hup();
+
+our $workers = 2;
+
+workers($workers);
+if ($workers > 1) {
+    master_on();
+}
+
+plan_tests(6);
+run_tests();
+
+__DATA__
+
+=== TEST 1: proxy_wasm metrics shm - record_metric, histogram - sanity
+--- skip_no_debug
+--- valgrind
+--- load_nginx_modules: ngx_http_echo_module
+--- wasm_modules: hostcalls
+--- config
+    location /t {
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=1';
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=2';
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=3';
+
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=10';
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=20';
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=30';
+        echo ok;
+    }
+--- grep_error_log eval: qr/histogram "\d+":( \d+: \d+;)+/
+--- grep_error_log_out eval
+qr/histogram "\d+": 1: 1; 2: 1; 4: 1; 16: 1; 32: 2; 4294967295: 0;/
+--- no_error_log
+[error]
+[crit]
+[emerg]
+[alert]
+
+
+
+=== TEST 2: proxy_wasm metrics shm - record_metric, histogram - on_configure
+--- skip_no_debug
+--- workers: 2
+--- valgrind
+--- load_nginx_modules: ngx_http_echo_module
+--- wasm_modules: hostcalls
+--- config
+    location /t {
+        proxy_wasm hostcalls 'on_configure=define_and_record_histograms \
+                              test=/t/metrics/record_histograms \
+                              metrics=h1 \
+                              value=10';
+        echo ok;
+    }
+--- grep_error_log eval: qr/histogram "\d+":( \d+: \d+;)+/
+--- grep_error_log_out eval
+qr/histogram "\d+": 16: 3; 4294967295: 0;/
+--- no_error_log
+[error]
+[crit]
+[emerg]
+[alert]
+
+
+
+=== TEST 3: proxy_wasm metrics - record_metric(), histogram - on_tick
+--- skip_no_debug
+--- wasm_modules: hostcalls
+--- load_nginx_modules: ngx_http_echo_module
+--- config eval
+my $filters;
+
+foreach my $wid (0 .. $::workers - 1) {
+    $filters .= "
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              on_tick=record_histograms \
+                              tick_period=100 \
+                              n_sync_calls=1 \
+                              on_worker=$wid \
+                              value=$wid \
+                              metrics=h2';";
+}
+qq{
+    location /t {
+        $filters
+
+        echo ok;
+    }
+}
+--- grep_error_log eval: qr/histogram "\d+":( \d+: \d+;)+/
+--- grep_error_log_out eval
+qr/histogram "\d+": 1: 2; 4294967295: 0;/
+--- no_error_log
+[error]
+[crit]
+[emerg]
+[alert]
+
+
+
+=== TEST 4: proxy_wasm metrics - record_metric(), histogram - on: request_headers, request_body, response_headers, response_body
+--- skip_no_debug
+--- load_nginx_modules: ngx_http_echo_module
+--- wasm_modules: hostcalls
+--- config eval
+my $phases = CORE::join(',', qw(
+    request_headers
+    request_body
+    response_headers
+    response_body
+));
+
+qq{
+    location /t {
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              on=$phases \
+                              test=/t/metrics/record_histograms \
+                              value=100 \
+                              metrics=h1';
+        echo ok;
+    }
+}
+--- request
+POST /t
+hello
+--- grep_error_log eval: qr/histogram "\d+":( \d+: \d+;)+/
+--- grep_error_log_out eval
+qr/histogram "\d+": 128: 4; 4294967295: 0;/
+--- no_error_log
+[error]
+[crit]
+[emerg]
+[alert]
+
+
+
+=== TEST 5: proxy_wasm metrics - record_metric(), histogram - on_http_call_response
+--- skip_no_debug
+--- wasm_modules: hostcalls
+--- load_nginx_modules: ngx_http_echo_module
+--- http_config eval
+--- config eval
+qq{
+    listen unix:$ENV{TEST_NGINX_UNIX_SOCKET};
+
+    location /dispatched {
+        return 200 "Hello back";
+    }
+
+    location /t {
+        proxy_wasm hostcalls 'on_configure=define_metrics \
+                              test=/t/dispatch_http_call \
+                              host=unix:$ENV{TEST_NGINX_UNIX_SOCKET} \
+                              path=/dispatched \
+                              on_http_call_response=record_histograms \
+                              value=1000 \
+                              metrics=h2';
+        echo ok;
+    }
+}
+--- grep_error_log eval: qr/histogram "\d+":( \d+: \d+;)+/
+--- grep_error_log_out eval
+qr/histogram "\d+": 1024: 1; 4294967295: 0;/
+--- no_error_log
+[error]
+[crit]
+[emerg]
+[alert]