Backend API. Server-side code: this runs in a Codename One backend, not in the app on the device.
public final class OtlpTracer
- Object
- OtlpTracer
ImplementsTracer
OpenTelemetry tracing over OTLP/HTTP, with no OpenTelemetry library behind it.
The OpenTelemetry Java SDK cannot run here: the server is translated to C against a Java subset with no reflection and no service loading, and a binary that linked the SDK would be carrying it whether or not anyone traced. This is the part of it a server actually needs – W3C trace context, the standard samplers, a bounded batch exporter, and the OTLP wire format in both its encodings – and it is only in the binary when the project enables it.
Configured the way every OpenTelemetry SDK is, so operations tooling works
unchanged. Each setting has a cn1.otel.* key, readable from
application.properties like any other, and the standard OTEL_*
environment variable is honoured for it too:
| key | variable | default |
|---|---|---|
| cn1.otel.endpoint | OTEL_EXPORTER_OTLP_ENDPOINT | http://localhost:4318; /v1/traces is appended |
| cn1.otel.traces.endpoint | OTEL_EXPORTER_OTLP_TRACES_ENDPOINT | used as it is, and wins over the one above |
| cn1.otel.headers | OTEL_EXPORTER_OTLP_HEADERS | none; name=value,name=value |
| cn1.otel.protocol | OTEL_EXPORTER_OTLP_PROTOCOL | http/protobuf, or http/json |
| cn1.otel.service.name | OTEL_SERVICE_NAME | what the build named it, else unknown_service |
| cn1.otel.resource.attributes | OTEL_RESOURCE_ATTRIBUTES | none |
| cn1.otel.sampler | OTEL_TRACES_SAMPLER | parentbased_always_on |
| cn1.otel.sampler.arg | OTEL_TRACES_SAMPLER_ARG | the ratio, 1 |
| cn1.otel.disabled | OTEL_SDK_DISABLED | false |
cn1.otel.attributes.exclude names attributes never to record, as a
comma separated list (db.query.text,user_agent.original), and
cn1.otel.relay=true opens the endpoint the app’s own spans are relayed
through; see OtlpRelay.
Fields
Constructors
public OtlpTracer() | A tracer whose service name comes from configuration alone. |
public OtlpTracer(String defaultServiceName) |
Methods
public static OtlpTracer open(Config config, String defaultServiceName)
throws IOException | A tracer opened against config, or null when the configuration turns tracing off. |
public boolean open(Config config)
throws IOException | Reads the settings and starts whatever exports spans. |
public Span startSpan(String name, int kind, Span parent, String traceparent, String tracestate) | A new span. |
public void flush(int timeoutMillis) | Blocks until what has ended so far is exported, or the time runs out. |
public void shutdown(int timeoutMillis) | Flushes, then stops the exporter. |
public HttpServer.Handler relay() | The handler that relays client spans to the collector, or null when this deployment does not offer one. |
public void metrics(Map out) | Adds this tracer’s counters to a metrics snapshot. |
Inherited methods
Field details
DISABLED
public static final String DISABLED = "cn1.otel.disabled"ENDPOINT
public static final String ENDPOINT = "cn1.otel.endpoint"TRACES_ENDPOINT
public static final String TRACES_ENDPOINT = "cn1.otel.traces.endpoint"HEADERS
public static final String HEADERS = "cn1.otel.headers"TRACES_HEADERS
public static final String TRACES_HEADERS = "cn1.otel.traces.headers"PROTOCOL
public static final String PROTOCOL = "cn1.otel.protocol"TRACES_PROTOCOL
public static final String TRACES_PROTOCOL = "cn1.otel.traces.protocol"SERVICE_NAME
public static final String SERVICE_NAME = "cn1.otel.service.name"RESOURCE_ATTRIBUTES
public static final String RESOURCE_ATTRIBUTES = "cn1.otel.resource.attributes"SAMPLER
public static final String SAMPLER = "cn1.otel.sampler"SAMPLER_ARG
public static final String SAMPLER_ARG = "cn1.otel.sampler.arg"ATTRIBUTES_EXCLUDE
public static final String ATTRIBUTES_EXCLUDE = "cn1.otel.attributes.exclude"QUEUE_SIZE
public static final String QUEUE_SIZE = "cn1.otel.queue.size"BATCH_SIZE
public static final String BATCH_SIZE = "cn1.otel.batch.size"EXPORT_DELAY
public static final String EXPORT_DELAY = "cn1.otel.export.delayMillis"RELAY
public static final String RELAY = "cn1.otel.relay"RELAY_PATH
public static final String RELAY_PATH = "cn1.otel.relay.path"RELAY_TOKEN
public static final String RELAY_TOKEN = "cn1.otel.relay.token"RELAY_MAX_BYTES
public static final String RELAY_MAX_BYTES = "cn1.otel.relay.maxBytes"RELAY_MAX_SPANS
public static final String RELAY_MAX_SPANS = "cn1.otel.relay.maxSpans"RELAY_CORS_ORIGIN
public static final String RELAY_CORS_ORIGIN = "cn1.otel.relay.corsOrigin"Constructor details
OtlpTracer
public OtlpTracer()A tracer whose service name comes from configuration alone.
OtlpTracer
public OtlpTracer(String defaultServiceName)Parameters
defaultServiceNameString- used when neither
cn1.otel.service.namenorOTEL_SERVICE_NAMEis set; the build passes the name@OpenTelemetrygave
Method details
open
public static OtlpTracer open(Config config, String defaultServiceName)
throws IOExceptionA tracer opened against config, or null when the configuration
turns tracing off. For a program that starts HttpServer or the
Lambda loop itself:
Tracing.install(OtlpTracer.open(Config.load(), "orders"));
Throws
open
public boolean open(Config config)
throws IOExceptionReads the settings and starts whatever exports spans. Called once, by
Backend.Builder.start or by the application before
Tracing.install.Returns
false when the configuration turned tracing off, in which case the
tracer is not installed and nothing was started
Throws
startSpan
public Span startSpan(String name, int kind, Span parent, String traceparent, String tracestate)A new span. Never null: a span the sampler declines is a non-recording one
that still carries its trace context.
Parameters
nameString- Not documented.
kindint- Not documented.
parentSpan- the local parent, or null
traceparentString- a remote parent’s
traceparentheader, used whenparentis null; null or malformed starts a new trace tracestateString- the remote parent’s
tracestate, or null
flush
public void flush(int timeoutMillis)Blocks until what has ended so far is exported, or the time runs out. A
Lambda host freezes the process between invocations, so a background
exporter there only runs when something waits for it.
shutdown
public void shutdown(int timeoutMillis)Flushes, then stops the exporter.
relay
public HttpServer.Handler relay()The handler that relays client spans to the collector, or null when this
deployment does not offer one. The builder puts it ahead of the routers.
metrics
public void metrics(Map out)Adds this tracer’s counters to a metrics snapshot.