Version 1.9.0

Note that due to an issue in publishing of Java artifacts, the 1.8.0 version has been skipped. The version before this one is 1.7.1.

General

• IMPORTANT: The deprecated io.opentelemetry:opentelemetry-proto module was removed. Java bindings for OTLP protobufs are now published via opentelemetry-proto-java, and available at maven coordinates io.opentelemetry.proto:opentelemetry-proto.

API

• New AttributesBuilder#remove(String) and AttributeBuilder#removeIf(Predicate<AttributeKey<?>>) methods improve ergonomics of modifying attributes.
• W3CBaggagePropagator now encodes baggage values in URL encoded UTF-8 format, per the W3C Baggage Specification.

SDK

• DelegatingSpanData has been promoted from incubation and is now available in the Trace SDK. The DelegatingSpanData class in the io.opentelemetry:opentelemetry-sdk-extension-tracing-incubator module is now deprecated.

Exporters

• The prometheus metric exporter now includes the time_unix_nano representing the epoch timestamp when collection occurred.
• The OTLP grpc exporters (OtlpGrpcSpanExporter, OtlpGrpcLogExporter, and OtlpGrpcMetricExporter) now include a default client implementation (okhttp). If a grpc implementation is detected on the classpath it will be used, but the exporters now work "out of the box" with no additional dependencies.

SDK Extensions

• IMPORTANT: The deprecated io.opentelemetry:opentelemetry-sdk-extension-async-processor module was removed. This module is now published via opentelemetry-java-contrib, and available at maven coordinates io.opentelemetry.contrib:opentelemetry-disruptor-processor.
• The ExecutorServiceSpanProcessor from the io.opentelemetry:opentelemetry-sdk-extension-tracing-incubator module is now deprecated.

Logging (alpha)

• This release includes a rework of the Log SDK to implement OTEP-0150 and to have more symmetry to the Trace SDK. LogSink is now LogEmitter. LogEmitter instances are obtained from SdkLogEmitterProvider. Other additions include MultiLogProcessor (accessed via LogProcessor#composite(...)), SimpleLogProcessor, InMemoryLogExporter, OtlpJsonLoggingLogExporter, and SystemOutLogExporter.
• The Log SDK maven coordinates have changed from io.opentelemetry:opentelemetry-sdk-extension-logging to io.opentelemetry:opentelemetry-sdk-logs.

Metrics (alpha)

• The new InMemoryMetricReader() constructor has been deprecated. Use InMemoryMetricReader.create() instead.
• A typo in Aggregation.explictBucketHistogram() has been fixed, and is now accessible at Aggregation.explicitBucketHistogram().
• The PeriodicMetricReader#builder(MetricExporter) builder replaces PeriodicMetricReader#newMetricReaderFactory(MetricExporter, Duration).
• Aggregation temporality is now influenced by metric exporters, and the ability to configure aggregation temporality via the view API has been removed. For example, the OTLP metric exporters support both DELTA and CUMULATIVE temporality. CUMULATIVE is the default preferred, but this can be changed either via programmatic configuration or
  via OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY if using autoconfigure.
• The MeterProvider#get(String instrumentationName, String instrumentationVersion, String schemaUrl) method is deprecated. Use MeterProvider#meterBuilder(String instrumentationName) with corresponding builder setters instead.
• Metric cardinality defenses have been added. Each instrument view now can have at most 2000 distinct metric streams per collection cycle. Recordings for additional streams are dropped with a diagnostic log message. Additionally, cumulative metric streams (both for synchronous and asynchronous instruments) are aggressively forgotten each time a metric export occurs that does not include recordings for a particular stream. The net effect is that there is now a cap on metric memory consumption.

Auto-configuration (alpha)

• BREAKING CHANGE: Remove deprecated otel.experimental.exporter.otlp.protocol, otel.experimental.exporter.otlp.{signal}.protocol properties. Please use otel.exporter.otlp.protocol, otel.exporter.otlp.{signal}.protocol instead.
• The autoconfigure module has introduced a powerful new AutoConfiguredOpenTelemetrySdkBuilder, and SPI for programmatically configuring the builder with AutoConfigurationCustomizerProvider. This provides improved ergonomics and control around autoconfigure customization.
• Added experimental support for enabling OTLP retry support for the grpc exporters. If enabled via otel.experimental.exporter.otlp.retry.enabled, a default retry policy will be used.
• The metric export interval of PeriodicMetricReader is now configured via otel.metric.export.interval. The existing otel.imr.export.interval property has been deprecated.
• The SPI classloader can now be specified when using the autoconfigure module programmatically.