3 files changed, 33 insertions, 13 deletions
diff --git a/u/trace/metrics.ts b/u/trace/metrics.ts
index a26ee5d..4ddde06 100644
--- a/u/trace/metrics.ts
+++ b/u/trace/metrics.ts
@@ -4,6 +4,7 @@ import {
   type ITraceWith,
   type Mapper,
   type SideEffect,
+  type Supplier,
 } from "@emprespresso/pengueno";
 
 export enum Unit {
@@ -16,10 +17,13 @@ export interface IMetric {
   readonly time: IEmittableMetric;
   readonly failure: IMetric;
   readonly success: IMetric;
-  readonly _isIMetric: true;
+  readonly warn: IMetric;
+  readonly children: Supplier<Array<IMetric>>;
+
+  readonly _tag: "IMetric";
 }
 export const isIMetric = (t: unknown): t is IMetric =>
-  isObject(t) && "_isIMetric" in t;
+  isObject(t) && "_tag" in t && t._tag === "IMetric";
 
 export interface IEmittableMetric {
   readonly name: string;
@@ -35,9 +39,9 @@ export class EmittableMetric implements IEmittableMetric {
     return {
       name: this.name,
       unit: this.unit,
-      _isMetricValue: true as true,
       emissionTimestamp: Date.now(),
       value,
+      _tag: "MetricValue",
     };
   }
 }
@@ -48,15 +52,21 @@ export class Metric implements IMetric {
     public readonly time: IEmittableMetric,
     public readonly failure: Metric,
     public readonly success: Metric,
-    public readonly _isIMetric: true = true,
+    public readonly warn: Metric,
+    public readonly _tag: "IMetric" = "IMetric",
   ) {}
 
+  public children() {
+    return [this.failure, this.success, this.warn];
+  }
+
   static fromName(name: string): Metric {
     return new Metric(
       new EmittableMetric(`${name}.count`, Unit.COUNT),
       new EmittableMetric(`${name}.elapsed`, Unit.MILLISECONDS),
       Metric.fromName(`${name}.failure`),
       Metric.fromName(`${name}.success`),
+      Metric.fromName(`${name}.warn`),
     );
   }
 }
@@ -66,10 +76,10 @@ export interface MetricValue {
   readonly unit: Unit;
   readonly value: number;
   readonly emissionTimestamp: number;
-  readonly _isMetricValue: true;
+  readonly _tag: "MetricValue";
 }
 export const isMetricValue = (t: unknown): t is MetricValue =>
-  isObject(t) && "_isMetricValue" in t;
+  isObject(t) && "_tag" in t && t._tag === "MetricValue";
 
 export const isMetricsTraceSupplier = (t: unknown): t is MetricsTraceSupplier =>
   isMetricValue(t) || isIMetric(t);
@@ -98,7 +108,7 @@ export class MetricsTrace implements ITrace<MetricsTraceSupplier> {
     const foundMetricValues = this.tracing.flatMap((
       [tracing, startedTracing],
     ) =>
-      [tracing, tracing.success, tracing.failure]
+      [tracing, ...tracing.children()]
         .filter((_tracing) => metric === _tracing)
         .flatMap((metric) => [
           this.addMetric(metric, startedTracing),
diff --git a/u/trace/trace.ts b/u/trace/trace.ts
index 72d4eef..e942066 100644
--- a/u/trace/trace.ts
+++ b/u/trace/trace.ts
@@ -41,18 +41,18 @@ export type LogMetricTraceSupplier = ITraceWith<
 >;
 export class LogMetricTrace implements ITrace<LogMetricTraceSupplier> {
   constructor(
-    private readonly logTrace: ITrace<LogTraceSupplier>,
-    private readonly metricsTrace: ITrace<MetricsTraceSupplier>,
+    private logTrace: ITrace<LogTraceSupplier>,
+    private metricsTrace: ITrace<MetricsTraceSupplier>,
   ) {}
 
   public addTrace(
     trace: LogTraceSupplier | MetricsTraceSupplier,
   ): LogMetricTrace {
     if (isMetricsTraceSupplier(trace)) {
-      this.metricsTrace.addTrace(trace);
+      this.metricsTrace = this.metricsTrace.addTrace(trace);
       return this;
     }
-    this.logTrace.addTrace(trace);
+    this.logTrace = this.logTrace.addTrace(trace);
     return this;
   }
 
diff --git a/u/trace/util.ts b/u/trace/util.ts
index dd8fb0d..302c8e4 100644
--- a/u/trace/util.ts
+++ b/u/trace/util.ts
@@ -7,6 +7,16 @@ import type {
 } from "@emprespresso/pengueno";
 
 export class TraceUtil {
+  static withTrace<T, Trace>(
+    trace: string,
+  ): ITraceableMapper<
+    T,
+    ITraceableTuple<T, Trace | Array<Trace>>,
+    Trace
+  > {
+    return (t) => [t.get(), `[${trace}]`];
+  }
+
   static withMetricTrace<T, Trace extends MetricsTraceSupplier>(
     metric: IMetric,
   ): ITraceableMapper<
@@ -24,7 +34,7 @@ export class TraceUtil {
     ITraceableTuple<T, Trace | Array<Trace>>,
     Trace
   > {
-    return (t) => [t.get(), `[${f.name}]`];
+    return TraceUtil.withTrace(f.name);
   }
 
   static withClassTrace<C extends object, T, Trace>(
@@ -34,7 +44,7 @@ export class TraceUtil {
     ITraceableTuple<T, Trace | Array<Trace>>,
     Trace
   > {
-    return (t) => [t.get(), `[${c.constructor.name}]`];
+    return TraceUtil.withTrace(c.constructor.name);
   }
 
   static promiseify<T, U, Trace>(