com.stuartsierra.component — com.stuartsierra/component 1.1.0

dependencies clj/s

(dependencies component)

Returns the map of other components on which this component depends.

dependency-graph clj/s

(dependency-graph system component-keys)

Returns a dependency graph, using the data structures defined in com.stuartsierra.dependency, for the components found by (select-keys system component-keys)

ex-component? clj/s

(ex-component? error)

True if the error has ex-data indicating it was thrown by something in the com.stuartsierra.component namespace.

ex-without-components clj/s

(ex-without-components error)

If the error has ex-data provided by the com.stuartsierra.component namespace, returns a new exception instance with the :component and :system removed from its ex-data. Preserves the other details of the original error. If the error was not created by this namespace, returns it unchanged. Use this when you want to catch and rethrow exceptions without including the full component or system.

Lifecycle clj/s protocol

start clj/s

(start component)

Begins operation of this component. Synchronous, does not return until the component is started. Returns an updated version of this component.

stop clj/s

(stop component)

Ceases operation of this component. Synchronous, does not return until the component is stopped. Returns an updated version of this component.

start-system clj/s

(start-system system)

(start-system system component-keys)

Recursively starts all components in the system, in dependency order, assoc'ing in their dependencies along the way.

The 2-argument arity selects which components to start, but this is a historical implementation detail. Use subsystem instead.

stop-system clj/s

(stop-system system)

(stop-system system component-keys)

Recursively stops all components in the system, in reverse dependency order.

The 2-argument arity selects which components to start, but this is a historical implementation detail. Use subsystem instead.

subsystem clj/s

(subsystem system subsystem-keys)

Returns a system containing only components associated with the keys in subsystem-keys, along with all of their transitive dependencies.

system-map clj/s

(system-map & keyvals)

Returns a system constructed of key/value pairs. The system has default implementations of the Lifecycle 'start' and 'stop' methods which recursively start/stop all components in the system.

System maps print as #<SystemMap> to avoid overwhelming the printer with large objects. As a consequence, printed system maps cannot be 'read'. To disable this behavior and print system maps like normal records, call (remove-method clojure.core/print-method com.stuartsierra.component.SystemMap)

system-using clj/s

(system-using system dependency-map)

Associates dependency metadata with multiple components in the system. dependency-map is a map of keys in the system to maps or vectors specifying the dependencies of the component at that key in the system, as per 'using'.

SystemMap clj/s

update-system clj/s

(update-system system component-keys f & args)

Invokes (apply f component args) on each of the components at component-keys in the system, in dependency order. Before invoking f, assoc's updated dependencies of the component.

update-system-reverse clj/s

(update-system-reverse system component-keys f & args)

Like update-system but operates in reverse dependency order.

using clj/s

(using component dependencies)

Associates metadata with component describing the other components on which it depends. Component dependencies are specified as a map. Keys in the map correspond to keys in this component which must be provided by its containing system. Values in the map are the keys in the system at which those components may be found. Alternatively, if the keys are the same in both the component and its enclosing system, they may be specified as a vector of keys.