CAS - OpenTelemetry Distributed Tracing
OpenTelemetry (Otel) is a collection of standardized vendor-agnostic tools, APIs, and SDKs. It allows us to instrument, generate, and collect telemetry data, which helps in analyzing application behavior or performance. Telemetry data can include logs, metrics, and traces. We can either automatically or manually instrument the code for HTTP, DB calls, and more.
Support is enabled by including the following dependency in the WAR overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-tracing-otel</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-tracing-otel:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-tracing-otel"
}
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dependencies {
/*
The following platform references are included automatically and are listed for reference only.
implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
*/
implementation "org.apereo.cas:cas-server-support-tracing-otel"
}
The following settings and properties are available from the CAS configuration catalog:
management.opentelemetry.enabledWhether OpenTelemetry should be enabled.
trueWhether OpenTelemetry should be enabled. If OpenTelemetry is disabled, only propagators are configured. Metrics, traces, and logging will use no-op implementations.
management.opentelemetry.logging.export.max-batch-sizeMaximum batch size for each export.
512Maximum batch size for each export. This must be less than or equal to 'maxQueueSize'.
management.opentelemetry.logging.export.max-queue-sizeMaximum number of logs that are kept in the queue before they will be dropped.
2048Maximum number of logs that are kept in the queue before they will be dropped.
management.opentelemetry.logging.export.otlp.compressionMethod used to compress the payload.
noneMethod used to compress the payload.
management.opentelemetry.logging.export.otlp.connect-timeoutConnect timeout for the OTel collector connection.
10sConnect timeout for the OTel collector connection.
management.opentelemetry.logging.export.otlp.endpointURL to the OTel collector's HTTP API.
URL to the OTel collector's HTTP API.
management.opentelemetry.logging.export.otlp.headersCustom HTTP headers you want to pass to the collector, for example auth headers.
Custom HTTP headers you want to pass to the collector, for example auth headers.
management.opentelemetry.logging.export.otlp.ssl.bundleSSL bundle name.
SSL bundle name.
management.opentelemetry.logging.export.otlp.timeoutCall timeout for the OTel Collector to process an exported batch of data.
10sCall timeout for the OTel Collector to process an exported batch of data. This timeout spans the entire call: resolving DNS, connecting, writing the request body, server processing, and reading the response body. If the call requires redirects or retries all must complete within one timeout period.
management.opentelemetry.logging.export.otlp.transportTransport used to send the logs.
httpTransport used to send the logs.
management.opentelemetry.logging.export.schedule-delayThe delay interval between two consecutive exports.
1sThe delay interval between two consecutive exports.
management.opentelemetry.logging.export.timeoutMaximum time an export will be allowed to run before being cancelled.
30sMaximum time an export will be allowed to run before being cancelled.
management.opentelemetry.logging.limits.max-attribute-value-lengthMaximum number of characters for string attribute values.
Maximum number of characters for string attribute values.
management.opentelemetry.logging.limits.max-attributesMaximum number of attributes per log record.
128Maximum number of attributes per log record.
management.opentelemetry.map-environment-variablesWhether to map OpenTelemetry SDK environment variables to Spring Boot configuration properties.
trueWhether to map OpenTelemetry SDK environment variables to Spring Boot configuration properties.
management.opentelemetry.otlp.compressionMethod used to compress the payload.
Method used to compress the payload.
management.opentelemetry.otlp.endpointOTLP endpoint to connect to.
OTLP endpoint to connect to.
management.opentelemetry.otlp.headersAdditional headers to be passed with every request.
Additional headers to be passed with every request.
management.opentelemetry.resource-attributesResource attributes.
Resource attributes.
management.opentelemetry.tracing.export.include-unsampledWhether unsampled spans should be exported.
falseWhether unsampled spans should be exported.
management.opentelemetry.tracing.export.max-batch-sizeMaximum batch size for each export.
512Maximum batch size for each export. This must be less than or equal to 'maxQueueSize'.
management.opentelemetry.tracing.export.max-queue-sizeMaximum number of spans that are kept in the queue before they will be dropped.
2048Maximum number of spans that are kept in the queue before they will be dropped.
management.opentelemetry.tracing.export.otlp.compressionMethod used to compress the payload.
noneMethod used to compress the payload.
management.opentelemetry.tracing.export.otlp.connect-timeoutConnect timeout for the OTel collector connection.
10sConnect timeout for the OTel collector connection.
management.opentelemetry.tracing.export.otlp.endpointURL to the OTel collector's HTTP API.
URL to the OTel collector's HTTP API.
management.opentelemetry.tracing.export.otlp.headersCustom HTTP headers you want to pass to the collector, for example auth headers.
Custom HTTP headers you want to pass to the collector, for example auth headers.
management.opentelemetry.tracing.export.otlp.ssl.bundleSSL bundle name.
SSL bundle name.
management.opentelemetry.tracing.export.otlp.timeoutCall timeout for the OTel Collector to process an exported batch of data.
10sCall timeout for the OTel Collector to process an exported batch of data. This timeout spans the entire call: resolving DNS, connecting, writing the request body, server processing, and reading the response body. If the call requires redirects or retries all must complete within one timeout period.
management.opentelemetry.tracing.export.otlp.transportTransport used to send the spans.
httpTransport used to send the spans.
management.opentelemetry.tracing.export.schedule-delayThe delay interval between two consecutive exports.
5sThe delay interval between two consecutive exports.
management.opentelemetry.tracing.export.timeoutMaximum time an export will be allowed to run before being cancelled.
30sMaximum time an export will be allowed to run before being cancelled.
management.opentelemetry.tracing.limits.max-attribute-value-lengthMaximum number of characters for string attribute values.
Maximum number of characters for string attribute values.
management.opentelemetry.tracing.limits.max-attributesMaximum number of attributes per span.
128Maximum number of attributes per span.
management.opentelemetry.tracing.limits.max-attributes-per-eventMaximum number of attributes per event.
128Maximum number of attributes per event.
management.opentelemetry.tracing.limits.max-attributes-per-linkMaximum number of attributes per link.
128Maximum number of attributes per link.
management.opentelemetry.tracing.limits.max-eventsMaximum number of events per span.
128Maximum number of events per span.
management.opentelemetry.tracing.limits.max-linksMaximum number of links per span.
128Maximum number of links per span.
management.opentelemetry.tracing.samplerSampler to use.
parent-based-trace-id-ratioSampler to use.
Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.
Notes on configuration
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
Note
When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value.
The only possible exception to this rule is when naming actuator endpoints; The name of the
actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, especially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.