chore: cleaned up span format

Author: aryanjassal

src/tracer/Tracer.ts

@@ -1,48 +1,46 @@
-import type { SpanEvent } from './types.js';
-import { IdSortable, utils as idUtils } from '@matrixai/id';
+import type { SpanEvent, SpanId } from './types.js';
+import { IdSortable } from '@matrixai/id';
 
 class Tracer {
-  protected activeSpans: Map<string, string> = new Map();
+  protected activeSpans: Map<SpanId, string> = new Map();
   protected queue: Array<SpanEvent> = [];
   protected resolveWaitChunksP: (() => void) | undefined;
   protected ended: boolean = false;
   protected idGen = new IdSortable();
 
-  protected nextId(): string {
+  protected nextId(): SpanId {
     const result = this.idGen.next();
     if (result.done || result.value == null) {
       throw new Error('Unexpected end of id generator');
     }
-    return idUtils.toMultibase(result.value, 'base64');
+    return result.value.toMultibase('base32hex');
   }
 
   protected queueSpanEvent(evt: SpanEvent) {
     this.queue.push(evt);
     if (this.resolveWaitChunksP != null) this.resolveWaitChunksP();
   }
 
-  public startSpan(name: string, parentSpanId?: string): string {
+  public startSpan(name: string, parentSpanId?: SpanId): SpanId {
     const spanId = this.nextId();
     this.activeSpans.set(spanId, name);
     this.queueSpanEvent({
       type: 'start',
-      id: this.nextId(),
-      spanId: spanId,
-      parentSpanId: parentSpanId,
+      id: spanId,
+      parentId: parentSpanId,
       name: name,
     });
     return spanId;
   }
 
-  public endSpan(spanId: string): void {
+  public endSpan(spanId: SpanId): void {
     const name = this.activeSpans.get(spanId);
     if (!name) return;
     this.activeSpans.delete(spanId);
     this.queueSpanEvent({
-      type: 'end',
+      type: 'stop',
       id: this.nextId(),
-      spanId: spanId,
-      name: name,
+      startId: spanId,
     });
   }
 

src/tracer/types.ts

@@ -1,12 +1,26 @@
-type Span = {
-  spanId: string;
-  name: string;
-  parentSpanId?: string;
+type SpanId = string;
+
+/**
+ * A span is a virtual concept, not an actual object. A span is made up of
+ * multiple events. Each event gets its own ID. Each start event must be
+ * associated with a stop event, otherwise the span is considered to be
+ * ongoing.
+ */
+
+type SpanStart = {
+  type: 'start';
+  id: SpanId;
+  parentId?: SpanId;
+  name?: string;
 };
 
-type SpanEvent = Span & {
-  type: 'start' | 'end';
-  id: string;
+type SpanStop = {
+  type: 'stop';
+  id: SpanId;
+  startId: SpanId;
+  parentId?: SpanId;
 };
 
-export type { Span, SpanEvent };
+type SpanEvent = SpanStart | SpanStop;
+
+export type { SpanId, SpanEvent };