add nim-metrics -> logos openmetrics serializer

Makefile

@@ -152,7 +152,7 @@ testIntegration: | build deps
 		$(ENV_SCRIPT) nim testIntegration $(TEST_PARAMS) $(NIM_PARAMS) build.nims
 
 # Builds a C example that uses the libstorage C library and runs it
-testLibstorage: | build deps
+testLibstorageC: | build deps
 	$(MAKE) $(if $(ncpu),-j$(ncpu),) libstorage
 	cd tests/cbindings && \
 	if [ "$(detected_OS)" = "Windows" ]; then \
@@ -163,6 +163,10 @@ testLibstorage: | build deps
 		LD_LIBRARY_PATH=../../build ./storage; \
 	fi
 
+testLibstorage: | testLibstorageC
+	echo -e $(BUILD_MSG) "build/$@" && \
+		$(ENV_SCRIPT) nim testLibstorage $(TEST_PARAMS) $(NIM_PARAMS) build.nims
+
 # Builds and runs all tests
 testAll: | build deps
 	echo -e $(BUILD_MSG) "build/$@" && \

build.nims

@@ -69,18 +69,17 @@ task storage, "build logos storage binary":
 task mixTools, "build mix tools (mix_pool, mix_relay_dht)":
   let (desc, ec) = gorgeEx("git describe --always --dirty")
   let mixVersion =
-    if ec == 0 and desc.strip().len > 0: desc.strip() else: "unknown"
+    if ec == 0 and desc.strip().len > 0:
+      desc.strip()
+    else:
+      "unknown"
   let mixParams =
-    "-d:chronicles_runtime_filtering -d:chronicles_log_level=TRACE " &
-    "-d:mixVersion:" & mixVersion
+    "-d:chronicles_runtime_filtering -d:chronicles_log_level=TRACE " & "-d:mixVersion:" &
+    mixVersion
   buildBinary "mix_pool",
-    outName = "mix_pool",
-    srcDir = "tools/mix/",
-    params = mixParams
+    outName = "mix_pool", srcDir = "tools/mix/", params = mixParams
   buildBinary "mix_relay_dht",
-    outName = "mix_relay_dht",
-    srcDir = "tools/mix/",
-    params = mixParams
+    outName = "mix_relay_dht", srcDir = "tools/mix/", params = mixParams
 
 task testStorage, "Build & run Logos Storage tests":
   test "testStorage", outName = "testStorage"
@@ -94,6 +93,9 @@ task testIntegration, "Run integration tests":
   # test "testIntegration", params = "-d:chronicles_sinks=textlines[notimestamps,stdout],textlines[dynamic] " &
   #   "-d:chronicles_enabled_topics:integration:TRACE"
 
+task testLibstorage, "Run libstorage Nim tests":
+  test "testLibstorage", outName = "testLibstorage"
+
 task build, "build Logos Storage binary":
   storageTask()
 

library/logosmetrics.nim

@@ -0,0 +1,38 @@
+import std/[json, locks, times, sets]
+
+import pkg/metrics
+
+proc toJson(collector: Collector, metrics: var seq[JsonNode] = @[]) =
+  # We know the closure won't outlive `metrics` so this is
+  # an acceptable hack.
+  let metricsPtr = addr metrics
+
+  proc serializeMetric(
+      name: string,
+      value: float64,
+      labels: openArray[string] = [],
+      labelValues: openArray[string] = [],
+      timestamp: Time,
+  ) {.raises: [].} =
+    # The logos openmetrics format (https://github.com/logos-co/openmetrics-module)
+    # does not include the timestamp, so we don't include it either.
+    var labelMap = newJObject()
+    for i in 0 ..< labels.len:
+      labelMap[labels[i]] = %labelValues[i]
+
+    metricsPtr[].add(%*{"name": name, "value": value, "labels": labelMap})
+
+  collector.collect(serializeMetric)
+
+# Serializes all collectors in a given registry to a Logos openmetrics-compatible
+# format. Allows including only specific collectors by name.
+proc toJson*(registry: Registry, includeOnly: openArray[string] = []): JsonNode =
+  var metrics = newSeq[JsonNode]()
+  withLock registry.lock:
+    for collector in registry.collectors:
+      if includeOnly.len > 0:
+        if collector.name notin includeOnly:
+          continue
+      collector.toJson(metrics)
+
+  result = %*{"metrics": metrics}

tests/libstorage/logosmetrics.nim

@@ -0,0 +1,47 @@
+import std/json
+
+import pkg/unittest2
+import pkg/metrics
+
+import ../../library/logosmetrics
+
+declareCounter myCounter, "Parts Counter", ["part_type"]
+declareGauge myGauge, "My gauge"
+declareHistogram myHistogram, "My histogram", buckets = [0.0, 1.0, 2.0]
+
+suite "Metrics":
+  test "should serialize Nim metrics to Logos Metrics format":
+    myCounter.inc(labelValues = ["screws"])
+    myCounter.inc(labelValues = ["washers"])
+
+    myGauge.set(42.0)
+
+    myHistogram.observe(1)
+    myHistogram.observe(2)
+    myHistogram.observe(3)
+    myHistogram.observe(4)
+    myHistogram.observe(5)
+
+    let metrics = defaultRegistry.toJson(@["myCounter", "myGauge", "myHistogram"])
+
+    # Remove "created" metrics as we can't pin those down.
+    var filteredMetrics = %*{"metrics": @[]}
+    for metric in metrics["metrics"]:
+      if metric["name"].getStr() != "myCounter_created" and
+          metric["name"].getStr() != "myHistogram_created":
+        filteredMetrics["metrics"].add(metric)
+
+    check filteredMetrics ==
+      %*{
+        "metrics": [
+          {"name": "myCounter_total", "value": 1.0, "labels": {"part_type": "screws"}},
+          {"name": "myCounter_total", "value": 1.0, "labels": {"part_type": "washers"}},
+          {"name": "myGauge", "value": 42.0, "labels": {}},
+          {"name": "myHistogram_sum", "value": 15.0, "labels": {}},
+          {"name": "myHistogram_count", "value": 5.0, "labels": {}},
+          {"name": "myHistogram_bucket", "value": 0.0, "labels": {"le": "0.0"}},
+          {"name": "myHistogram_bucket", "value": 1.0, "labels": {"le": "1.0"}},
+          {"name": "myHistogram_bucket", "value": 2.0, "labels": {"le": "2.0"}},
+          {"name": "myHistogram_bucket", "value": 5.0, "labels": {"le": "+Inf"}},
+        ]
+      }

tests/testLibstorage.nim

@@ -0,0 +1,2 @@
+# Tests the Nim side of libstorage.
+import ./libstorage/logosmetrics