spring boot opentelemetry
1.0.0
Spring Boot Actuator provides dependency management and autoconfiguration for Micrometer, which offers a convenient facade over many different monitoring systems. One of them is OpenTelemetry.
Spring Boot developers can enable their applications to export metrics via the OTLP protocol to an OpenTelemetry backend by adding Spring Boot Actuator and the dedicated OpenTelemetry dependency from Micrometer to their projects.
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-actuator'
runtimeOnly 'io.micrometer:micrometer-registry-otlp'
...
}The exporter provided by the Micrometer Registry OTLP is an HTTP exporter and can be configured via properties thanks to the autoconfiguration for OpenTelemetry.
management:
otlp:
metrics:
export:
url: http://localhost:4318/v1/metrics
step: 5sOpenTelemetry supports additional key/value pairs (called resource attributes) to be included in the telemetry data. Spring Boot Actuator provides
autoconfiguration for those
and makes it possible to add new resource attributes via properties.
management:
opentelemetry:
resource-attributes:
cluster: local
"service.name": ${spring.application.name}I made a demo application to showcase this setup.
The Micrometer Registry OTLP module uses an OTLP-compatible HTTP client to export metrics to an OpenTelemetry backend.
Internally, the OtlpMeterRegistry uses a private HttpSender object to configure the HTTP client. The benefit of this
approach is that the module is lightweight and doesn't need any dependency on the OpenTelemetry SDK. It only uses the
io.opentelemetry.proto library which provides the protobuf configuration for OpenTelemetry.
On the other hand, such an approach means that:
The new generic OpenTelemetryAutoConfiguration in Spring Boot 3.2 autoconfigures an OpenTelemetry bean and makes it possible
to configure an SdkMeterProvider bean. What if Micrometer could use that for setting up the OpenTelemetry metrics exporter?
Possible solutions:
MeterRegistry that accepts an OpenTelemetry object
for configuration (similar to the OpenTelemetryMeterRegistry
used by the OpenTelemetry Java Instrumentation library). If backward compatibility is necessary, the new implementation would
need to co-exist with the existing one (maybe a feature flag could switch between the two?);I have submitted an issue to the Micrometer project and shared these suggestions. Building (or updating) such a module would make it possible
to re-use the same OpenTelemetryAutoConfiguration introduced in Spring Boot 3.2 for both metrics and traces (and, in the future, for logs as well).
SdkMeterProvider
bean and, in general, for using metrics with OpenTelemetry. But we are missing Micrometer support before that is doable.OtlpHttpMetricExporter or OtlpGrpcMetricExporter).For more context about the current challenges, refer to this issue on the Spring Boot project.
Spring Boot Actuator provides dependency management and autoconfiguration for Micrometer Tracing, which offers a convenient facade over a few different distributed tracing backends. One of them is OpenTelemetry.
Spring Boot developers can enable their applications to export traces via the OTLP protocol to an OpenTelemetry backend by adding Spring Boot Actuator, Micrometer Tracing and the dedicated OpenTelemetry dependency from Micrometer to their projects.
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'io.micrometer:micrometer-tracing-bridge-otel'
implementation 'io.opentelemetry:opentelemetry-exporter-otlp'
...
}The exporter provided by the Spring Boot Actuator autoconfiguration is an HTTP exporter (an OtlpHttpSpanExporter bean) and can be configured via properties thanks to the tracing configuration in OtlpAutoConfiguration.
management:
otlp:
tracing:
endpoint: http://localhost:4318/v1/tracesOpenTelemetry supports additional key/value pairs (called resource attributes) to be included in the telemetry data. Spring Boot Actuator provides autoconfiguration for those and makes it possible to add new resource attributes via properties. The standard OpenTelemetry service.name resource attribute is configured automatically to the value of spring.application.name (if defined) or else to a default application value.
management:
opentelemetry:
resource-attributes:
cluster: localI made a demo application to showcase this setup.
In this issue on the Spring Boot project, autoconfiguration for an OtlpHttpSpanExporter bean has been added to export traces via HTTP.
A common requirement is to export traces via gRPC (the most used approach in OpenTelemetry). Currently, developers can configure an OtlpGrpcSpanExporter bean by themselves. It would be nice if Spring Boot Actuator would provide autoconfiguration for that, enhancing the existing OtlpAutoConfiguration.
There is already an issue on the Spring Boot project to add such autoconfiguration.
Overall, these are the issues and suggestions I've been describing so far.
Micrometer
MeterRegistry implementation built on top of OpenTelemetry and configurable via its standard approaches, so that it's possible to share configuration between metrics and traces.Spring Boot Actuator
OpenTelemetry and Resource beans can be reused from the existing OpenTelemetry configuration. Besides that, the autoconfiguration should define defaults for SdkMeterProvider, OtlpHttpMetricExporter and OtlpGrpcMetricExporter.OtlpGrpcSpanExporter bean.Spring Initializr
Spring Boot Actuator
OpenTelemetry and Resource beans can be reused from the existing OpenTelemetry configuration. Besides that, the autoconfiguration should define defaults for SdkLoggerProvider, OtlpHttpLogRecordExporter and OtlpGrpcLogRecordExporter.OpenTelemetryAutoConfiguration (this issue might be considered for the global OpenTelemetryAutoConfiguration once the tracing specific one gets deleted).
