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std/otlp

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Types

Resource

struct Resource {
  service: Str
  attributes: List[(Str, Str)] = []
  scope: Str = "std/trace"
  version: Str = ""
}

What an export says about the program that made the spans: the service.name resource attribute, more resource attributes, and the instrumentation scope name (and version) the spans are filed under.

Source: std/otlp.xo:12

ExportErr

enum ExportErr {
  Transport(msg: Str)
  Rejected(status: Int, body: Str)
  GaveUp(status: Int, tries: Int)
}

Why an export failed: the transport (no response), a status the collector will not take (400 and the like: a retry would send the same bytes), or retries that ran out with the last answer.

Source: std/otlp.xo:35

ExportErr.display

fn (e: ExportErr) display() -> Str

export: MSG, export rejected: STATUS BODY, export gave up after N tries: STATUS.

Source: std/otlp.xo:42

Exporter

struct Exporter {
  client: http.Client
  endpoint: Str
  resource: Resource
  headers: Map[Str, Str]
  backoff: backoff.Backoff
  clock: Clock
  rand: Rand
}

Sends OTLP/HTTP requests (POST {endpoint}/v1/traces and /v1/metrics, Content-Type: application/x-protobuf) to a collector. 429, 502, 503 and 504 are retried with the schedule of backoff, waiting at least the Retry-After the collector asks for (in seconds); any other non 2xx status is not retried, as the OTLP specification says.

Source: std/otlp.xo:48

Exporter.with_headers

fn (e: Exporter) with_headers(h: Map[Str, Str]) -> Exporter

The exporter sending these headers on every request (an API key, Authorization).

Source: std/otlp.xo:61

Exporter.with_backoff

fn (e: Exporter) with_backoff(b: backoff.Backoff) -> Exporter

The exporter retrying on schedule b (5 tries by default).

Source: std/otlp.xo:63

Exporter.send_traces

fn (e: Exporter) send_traces(spans: List[trace.Span]) -> () ! ExportErr uses net.dial, clock, rand

Exports spans (one request; an empty list sends nothing).

Source: std/otlp.xo:65

Exporter.send_metrics

fn (e: Exporter) send_metrics(reg: metrics.Registry, start_ms: Int) -> () ! ExportErr uses net.dial, clock, rand

Exports the registry’s metrics (one request), every point cumulative since start_ms, stamped now.

Source: std/otlp.xo:67

Functions

encode_traces

fn encode_traces(res: Resource, spans: List[trace.Span]) -> Bytes

The body of an ExportTraceServiceRequest for spans (one ResourceSpans, one ScopeSpans). A span’s trace id is its request id when that is 32 hex digits, else the first 16 bytes of the SHA-256 of the id; the request span of an id is a server span with the id as its trace, its other spans are internal spans whose parent is that request span; span ids are the first 8 bytes of a SHA-256 of the span’s request id, name and start, so an export repeated after a retry names the same spans. A request span’s HTTP status becomes the span status (500 and above is an error) and the attribute http.response.status_code.

Source: std/otlp.xo:25

encode_metrics

fn encode_metrics(res: Resource, reg: metrics.Registry, start_ms: Int, now_ms: Int) -> Bytes

The body of an ExportMetricsServiceRequest for the families of reg (one ResourceMetrics, one ScopeMetrics), every point cumulative since start_ms and stamped now_ms (Unix milliseconds): a counter is a monotonic Sum, a gauge a Gauge, a histogram a Histogram (bucket counts per bucket, not cumulative, as OTLP has them), a summary a Summary with its count and sum (no quantile values); a label becomes a string attribute of the point.

Source: std/otlp.xo:31

exporter

fn exporter(client: http.Client, endpoint: Str, res: Resource, clock: Clock, rand: Rand) -> Exporter

An exporter to the collector at endpoint (http://host:4318, no path), for the spans and metrics of res.

Source: std/otlp.xo:59

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