Files
element-call/src/analytics/RageshakeSpanProcessor.ts

115 lines
3.1 KiB
TypeScript

import { Attributes } from "@opentelemetry/api";
import { hrTimeToMicroseconds } from "@opentelemetry/core";
import {
SpanProcessor,
ReadableSpan,
Span,
} from "@opentelemetry/sdk-trace-base";
const dumpAttributes = (attr: Attributes) =>
Object.entries(attr).map(([key, value]) => ({
key,
type: typeof value,
value,
}));
/**
* Exports spans on demand to the Jaeger JSON format, which can be attached to
* rageshakes and loaded into analysis tools like Jaeger and Stalk.
*/
export class RageshakeSpanProcessor implements SpanProcessor {
private readonly spans: ReadableSpan[] = [];
async forceFlush(): Promise<void> {}
onStart(span: Span): void {
this.spans.push(span);
}
onEnd(): void {}
/**
* Dumps the spans collected so far as Jaeger-compatible JSON.
*/
public dump(): string {
const now = Date.now() * 1000; // Jaeger works in microseconds
const traces = new Map<string, ReadableSpan[]>();
// Organize spans by their trace IDs
for (const span of this.spans) {
const traceId = span.spanContext().traceId;
let trace = traces.get(traceId);
if (trace === undefined) {
trace = [];
traces.set(traceId, trace);
}
trace.push(span);
}
const processId = "p1";
const processes = {
[processId]: {
serviceName: "element-call",
tags: [],
},
warnings: null,
};
return JSON.stringify({
// Honestly not sure what some of these fields mean, I just know that
// they're present in Jaeger JSON exports
total: 0,
limit: 0,
offset: 0,
errors: null,
data: [...traces.entries()].map(([traceId, spans]) => ({
traceID: traceId,
warnings: null,
processes,
spans: spans.map((span) => {
const ctx = span.spanContext();
const startTime = hrTimeToMicroseconds(span.startTime);
// If the span has not yet ended, pretend that it ends now
const duration =
span.duration[0] === -1
? now - startTime
: hrTimeToMicroseconds(span.duration);
return {
traceID: traceId,
spanID: ctx.spanId,
operationName: span.name,
processID: processId,
warnings: null,
startTime,
duration,
references:
span.parentSpanId === undefined
? []
: [
{
refType: "CHILD_OF",
traceID: traceId,
spanID: span.parentSpanId,
},
],
tags: dumpAttributes(span.attributes),
logs: span.events.map((event) => ({
timestamp: hrTimeToMicroseconds(event.time),
// The name of the event is in the "event" field, aparently.
fields: [
...dumpAttributes(event.attributes ?? {}),
{ key: "event", type: "string", value: event.name },
],
})),
};
}),
})),
});
}
async shutdown(): Promise<void> {}
}