Jaeger components implement various APIs for saving or retrieving trace data.

The following labels are used to describe API compatibility guarantees.

• stable - the API guarantees backwards compatibility. If breaking changes are going to be made in the future, they will result in a new API version, e.g. /api/v2 URL prefix or a different namespace in the IDL.
• internal - the APIs are intended for internal communications between Jaeger components and are not recommended for use by external components.
• deprecated - the APIs that are only maintained for legacy reasons and will be phased out in the future.

Since Jaeger v1.32, jaeger-collector and jaeger-query Service ports that serve gRPC endpoints enable gRPC reflection  . Unfortunately, the internally used gogo/protobuf has a compatibility issue  with the official golang/protobuf, and as a result only the list reflection command is currently working properly.

Span reporting APIs

jaeger-agent and jaeger-collector are the two components of the Jaeger backend that can receive spans. At this time they support two sets of non-overlapping APIs.

OpenTelemetry Protocol (stable)

Since v1.35, the Jaeger backend can receive trace data from the OpenTelemetry SDKs in their native OpenTelemetry Protocol (OTLP)  . It is no longer necessary to configure the OpenTelemetry SDKs with Jaeger exporters, nor deploy the OpenTelemetry Collector between the OpenTelemetry SDKs and the Jaeger backend.

The OTLP data is accepted in these formats: (1) binary gRPC, (2) Protobuf over HTTP, (3) JSON over HTTP. For more details on the OTLP receiver see the official documentation  . Note that not all configuration options are supported in jaeger-collector (see --collector.otlp.* CLI Flags ), and only tracing data is accepted, since Jaeger does not store other telemetry types.

Thrift over UDP (stable)

jaeger-agent can only receive spans over UDP in Thrift format. The primary API is a UDP packet that contains a Thrift-encoded Batch struct defined in the jaeger.thrift  IDL file, located in the jaeger-idl  repository. Most Jaeger Clients use Thrift’s compact encoding, however some client libraries do not support it (notably, Node.js) and use Thrift’s binary encoding (sent to a different UDP port). jaeger-agent’s API is defined by the agent.thrift  IDL file.

For legacy reasons, jaeger-agent also accepts spans over UDP in Zipkin format, however, only very old versions of Jaeger clients can send data in that format and it is officially deprecated.

Protobuf via gRPC (stable)

In a typical Jaeger deployment, jaeger-agents receive spans from Clients and forward them to jaeger-collectors. Since Jaeger v1.11, the official and recommended protocol between jaeger-agents and jaeger-collectors is jaeger.api_v2.CollectorService gRPC endpoint defined in collector.proto  IDL file. The same endpoint can be used to submit trace data from SDKs directly to jaeger-collector.

Thrift over HTTP (stable)

In some cases it is not feasible to deploy jaeger-agent next to the application, for example, when the application code is running as a serverless function. In these scenarios the SDKs can be configured to submit spans directly to jaeger-collectors over HTTP/HTTPS.

The same jaeger.thrift  payload can be submitted in an HTTP POST request to the /api/traces endpoint, for example, https://jaeger-collector:14268/api/traces. The Batch struct needs to be encoded using Thrift’s binary encoding, and the HTTP request should specify the content type header:

Content-Type: application/vnd.apache.thrift.binary

JSON over HTTP (n/a)

There is no official Jaeger JSON format that can be accepted by jaeger-collector. Jaeger does accept the OpenTelemetry protocol via JSON (see above ).

Zipkin Formats (stable)

jaeger-collector can also accept spans in several Zipkin data formats, namely JSON v1/v2 and Thrift. jaeger-collector needs to be configured to enable Zipkin HTTP server, e.g. on port 9411 used by Zipkin collectors. The server enables two endpoints that expect POST requests:

• /api/v1/spans for submitting spans in Zipkin JSON v1 or Zipkin Thrift format.
• /api/v2/spans for submitting spans in Zipkin JSON v2.

Trace retrieval APIs

Traces saved in the storage can be retrieved by calling jaeger-query Service.

gRPC/Protobuf (stable)

The recommended way for programmatically retrieving traces and other data is via the jaeger.api_v2.QueryService gRPC endpoint defined in query.proto  IDL file. In the default configuration this endpoint is accessible from jaeger-query:16685.

HTTP JSON (internal)

Jaeger UI communicates with jaeger-query Service via JSON API. For example, a trace can be retrieved via a GET request to https://jaeger-query:16686/api/traces/{trace-id-hex-string}. This JSON API is intentionally undocumented and subject to change.

Remote Storage API (stable)

When using the grpc storage type (a.k.a. remote storage ), Jaeger components can use custom storage backends as long as those backends implement the gRPC Remote Storage API  .

Remote Sampling Configuration (stable)

This API supports Jaeger’s Remote Sampling protocol, defined in the sampling.proto  IDL file.

Both jaeger-agent and jaeger-collector implement the API. See Remote Sampling for details on how to configure the Collector with sampling strategies. jaeger-agent is merely acting as a proxy to jaeger-collector.

The following table lists different endpoints and formats that can be used to query for sampling strategies. The official HTTP/JSON endpoints use standard Protobuf-to-JSON mapping  .

Examples

Run all-in-one in one terminal:

$ go run ./cmd/all-in-one \
  --sampling.strategies-file=cmd/all-in-one/sampling_strategies.json

Query different endpoints in another terminal:

# Collector
$ curl "http://localhost:14268/api/sampling?service=foo"
{"strategyType":"PROBABILISTIC","probabilisticSampling":{"samplingRate":1}}

# Agent
$ curl "http://localhost:5778/sampling?service=foo"
{"strategyType":"PROBABILISTIC","probabilisticSampling":{"samplingRate":1}}

# Agent, legacy endpoint / (not recommended)
$ curl "http://localhost:5778/?service=foo"
{"strategyType":0,"probabilisticSampling":{"samplingRate":1}}

Service dependencies graph (internal)

Can be retrieved fromjaeger-query Service at /api/dependencies endpoint. The GET request expects two parameters:

• endTs (number of milliseconds since epoch) - the end of the time interval
• lookback (in milliseconds) - the length the time interval (i.e. start-time + lookback = end-time).

The returned JSON is a list of edges represented as tuples (caller, callee, count).

For programmatic access to the service graph, the recommended API is gRPC/Protobuf described above.

Service Performance Monitoring (internal)

Please refer to the SPM Documentation