Configuration
Pedestal primarily is configured via the service map; however, there are sub-systems within Pedestal that can operate outside a service, or before a service map is used to create and start a server.
These sub-systems are:
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Tracing
For all but Developer Mode[1], Pedestal operates in terms of a configuration function: The configuration function is specified in one of several ways, and this is resolved to a particular var in a namespace, which is invoked to return a needed value.
Configuration Order
Pedestal uses late binding to configure these values, so that it is possible to customize Pedestal’s behavior to the operating environment: anything from local developer to final production.
Pedestal will search a series of sources for a value that identifies the var; these are in a specific order, with an eye towards making it possible to override the value at runtime for testing or production, as that is often a need for these subsystems.
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JVM system property name
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Environment Variable
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Entry in the
pedestal-test-config.ednresource -
Entry in the
pedestal-config.ednresource -
A hard-coded default, or nil
The intent is that a Pedestal application will typically include a pedestal-config.edn on the classpath (packaged with
the application’s sources or compiled classes, typically stored in resources); the pedestal-test-config.edn will
only be on the classpath during local testing (typically, stored in test-resources).
When necessary, these values can be overrridden when deployed to a staging or production deployment using environment variables or JVM system properties.
EDN Configuration Files
The contents of pedestal-config.edn (and pedestal-test-config.edn) are EDN maps.
The keys are the JVM property converted to a keyword (for example, :io.pedestal.log.overrideLogger).
For values that are function types, the config value can be either a qualified symbol, or a string that is converted to a qualified symbol.
For values that are boolean, the config value may be a boolean or a string.
Configuration Keys
Once a symbol is obtained from a configuration source, it is resolved to a Clojure Var. Each use of configuration has its own interpretation of the Var.
The following section list the current configuration values; each heading identifies the JVM system property, then the equivalent environment variable.
io.pedestal.log.overrideLogger / PEDESTAL_LOGGER
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type: function
Used to create an LoggerSource instance from a logger name;
If not specified, then org.slf4j.LoggerFactory.getLogger(java.lang.String) is used.
io.pedestal.log.formatter / PEDESTAL_LOG_FORMATTER
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type: function
A function used to format a logged event map to a string prior to being passed to the LoggerSource.
When not specified, pr-str is used.
io.pedestal.interceptor.disable-default-handler-names / PEDESTAL_DISABLE_DEFAULT_HANDLER_NAMES
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type: boolean
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default: false
If true, then Pedestal will not automatically convert handler function class names to an interceptor name (the interceptor will be anonymous instead).
io.pedestal.telemetry.metric-source / PEDESTAL_METRICS_SOURCE
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type: function
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default:
metric-source
A function that returns an instance of MetricSource used to create metrics used by
Pedestal or applications.
The default is to get the value from
io.opentelemetry.api.GlobalOpenTelemetry.getMeter(java.lang.String).
io.pedestal.telemetry.metric-value-type / PEDESTAL_METRICS_VALUE_TYPE
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type: keyword (:long or :double)
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default: :long
The kind of values provided to the MetricSource.
io.pedestal.telemetry.tracing-source/ PEDESTAL_TRACING_SOURCE
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type: function
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default:
tracing-source
A function that returns an instance of
TracingSource, used to emit tracing events.
The default, gets its value
from io.opentelemetry.api.GlobalOpenTelemetry.getTracer(java.lang.String).