Package com.yahoo.config.subscription
Class ConfigSubscriber
java.lang.Object
com.yahoo.config.subscription.ConfigSubscriber
- All Implemented Interfaces:
AutoCloseable
- Direct Known Subclasses:
GenericConfigSubscriber
Used for subscribing to one or more configs. Can optionally be given a
ConfigSource
for the configs
that will be used when subscribe(Class, String)
is called.
subscribe(Class, String)
on the configs needed, call nextConfig(boolean)
and get the config from the
ConfigHandle
which subscribe(Class, String)
returned.- Author:
- Vegard Havdal
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Nested Class Summary
Modifier and TypeClassDescriptionstatic interface
ConfigSubscriber.SingleSubscriber<T extends com.yahoo.config.ConfigInstance>
Convenience interface for clients who only subscribe to one config.protected static enum
The states of the subscriber. -
Field Summary
Modifier and TypeFieldDescriptionprotected final List<ConfigHandle<? extends com.yahoo.config.ConfigInstance>>
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Constructor Summary
ConstructorDescriptionConstructs a new subscriber.ConfigSubscriber
(ConfigSource source) Constructs a new subscriber with the given source. -
Method Summary
Modifier and TypeMethodDescriptionprotected void
void
close()
Closes all openConfigSubscription
sprotected void
finalize()
Finalizer to ensure that we do not leak resources on reconfig.long
The current generation of configs known by this subscriber.boolean
isClosed()
boolean
nextConfig
(boolean isInitializing) Use this for waiting for a new config that has changed.boolean
nextConfig
(long timeoutMillis, boolean isInitializing) Use this for waiting for a new config that has changed, with the given timeout.boolean
nextGeneration
(boolean isInitializing) Use this for waiting for a new config generation.boolean
nextGeneration
(long timeoutMillis, boolean isInitializing) Use this for waiting for a new config generation, with the given timeout Returns true if: It is the first time nextGeneration() is called on this subscriber, and the framework has fetched config for all subscriptions.void
reload
(long generation) Sets all subscriptions under this subscriber to have the given generation.startConfigThread
(Runnable runnable) Convenience method to start a daemon thread called "Vespa config thread" with the given runnable.protected ConfigSubscriber.State
state()
<T extends com.yahoo.config.ConfigInstance>
ConfigHandle<T>subscribe
(ConfigSubscriber.SingleSubscriber<T> singleSubscriber, Class<T> configClass, String configId) Convenience method that can be used if you only want to subscribe to one config, and want generic error handling.<T extends com.yahoo.config.ConfigInstance>
ConfigHandle<T>Subscribes on the given type ofConfigInstance
with the given config id.<T extends com.yahoo.config.ConfigInstance>
ConfigHandle<T>Subscribes on the given type ofConfigInstance
with the given config id and subscribe timeout.protected void
subscribeAndHandleErrors
(ConfigSubscription<?> sub, ConfigKey<?> configKey, ConfigHandle<?> handle, TimingValues timingValues) protected void
throwIfExceptionSet
(ConfigSubscription<? extends com.yahoo.config.ConfigInstance> sub) If aConfigSubscription
has its exception set, reset that field and throw ittoString()
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Field Details
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subscriptionHandles
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Constructor Details
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ConfigSubscriber
public ConfigSubscriber()Constructs a new subscriber. The default Vespa network config source will be used, which is the address of a config proxy running locally. It can also be changed by setting VESPA_CONFIG_SOURCES. -
ConfigSubscriber
Constructs a new subscriber with the given source.- Parameters:
source
- aConfigSource
that will be used whensubscribe(Class, String)
is called.
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Method Details
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subscribe
public <T extends com.yahoo.config.ConfigInstance> ConfigHandle<T> subscribe(Class<T> configClass, String configId) Subscribes on the given type ofConfigInstance
with the given config id. The method blocks until the first config is ready to be fetched withnextConfig(boolean)
.- Parameters:
configClass
- The class, typically generated from a def-file using config-class-pluginconfigId
- Identifies the service in vespa-services.xml, or null if you are using a localConfigSource
which does not use config id. Also supported: raw:, file:, dir: or jar: config id which addresses config locally in the same way.- Returns:
- a ConfigHandle
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subscribe
public <T extends com.yahoo.config.ConfigInstance> ConfigHandle<T> subscribe(Class<T> configClass, String configId, long timeoutMillis) Subscribes on the given type ofConfigInstance
with the given config id and subscribe timeout. The method blocks until the first config is ready to be fetched withnextConfig(boolean)
.- Parameters:
configClass
- The class, typically generated from a def-file using config-class-pluginconfigId
- Identifies the service in vespa-services.xml, or possibly raw:, file:, dir: or jar: type config which addresses config locally.timeoutMillis
- The time to wait for a config to become available, in milliseconds- Returns:
- a ConfigHandle
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checkStateBeforeSubscribe
protected void checkStateBeforeSubscribe() -
subscribeAndHandleErrors
protected void subscribeAndHandleErrors(ConfigSubscription<?> sub, ConfigKey<?> configKey, ConfigHandle<?> handle, TimingValues timingValues) -
nextConfig
public boolean nextConfig(boolean isInitializing) Use this for waiting for a new config that has changed. Returns true if: It is the first time nextConfig() is called on this subscriber, and the framework has fetched config for all subscriptions. (Typically a first time config.) or All configs for the subscriber have a new generation since the last time nextConfig() was called, AND they have the same generation AND there is a change in config for at least one of the configs. (Typically calls for a reconfig.) You can check which configs are changed by callingConfigHandle.isChanged()
on the handle you got fromsubscribe(Class, String)
. If the call times out (timeout 1000 ms), no handle will have the changed flag set. You should not configure anything then.- Parameters:
isInitializing
- true if this the config is needed to create the initial configuration for the caller, false if this is for reconfiguration- Returns:
- true if a config/reconfig of your system should happen
- Throws:
ConfigInterruptedException
- if thread performing this call interrupted.SubscriberClosedException
- if subscriber is closed
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nextConfig
public boolean nextConfig(long timeoutMillis, boolean isInitializing) Use this for waiting for a new config that has changed, with the given timeout. Returns true if: It is the first time nextConfig() is called on this subscriber, and the framework has fetched config for all subscriptions. (Typically a first time config.) or All configs for the subscriber have a new generation since the last time nextConfig() was called, AND they have the same generation AND there is a change in config for at least one of the configs. (Typically calls for a reconfig.) You can check which configs are changed by callingConfigHandle.isChanged()
on the handle you got fromsubscribe(Class, String)
. If the call times out, no handle will have the changed flag set. You should not configure anything then.- Parameters:
timeoutMillis
- timeout in millisecondsisInitializing
- true if this the config is needed to create the initial configuration for the caller, false if this is for reconfiguration- Returns:
- true if a config/reconfig of your system should happen
- Throws:
ConfigInterruptedException
- if thread performing this call interrupted.SubscriberClosedException
- if subscriber is closed
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nextGeneration
public boolean nextGeneration(boolean isInitializing) Use this for waiting for a new config generation. Returns true if: It is the first time nextGeneration() is called on this subscriber, and the framework has fetched config for all subscriptions. (Typically a first time config.) or All configs for the subscriber have a new generation since the last time nextGeneration() was called, AND they have the same generation. Note that none of the configs have to be changed, but they might be. You can check which configs are changed by callingConfigHandle.isChanged()
on the handle you got fromsubscribe(Class, String)
. If the call times out (timeout 1000 ms), no handle will have the changed flag set. You should not configure anything then.- Parameters:
isInitializing
- true if this the next generation is needed to create the initial configuration for the caller, false if this is for reconfiguration- Returns:
- true if generations for all configs have been updated.
- Throws:
ConfigInterruptedException
- if thread performing this call interrupted.SubscriberClosedException
- if subscriber is closed
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nextGeneration
public boolean nextGeneration(long timeoutMillis, boolean isInitializing) Use this for waiting for a new config generation, with the given timeout Returns true if: It is the first time nextGeneration() is called on this subscriber, and the framework has fetched config for all subscriptions. (Typically a first time config.) or All configs for the subscriber have a new generation since the last time nextGeneration() was called, AND they have the same generation. Note that none of the configs have to be changed, but they might be. You can check which configs are changed by callingConfigHandle.isChanged()
on the handle you got fromsubscribe(Class, String)
. If the call times out (timeout 1000 ms), no handle will have the changed flag set. You should not configure anything then.- Parameters:
timeoutMillis
- timeout in millisecondsisInitializing
- true if this the next generation is needed to create the initial configuration for the caller, false if this is for reconfiguration- Returns:
- true if generations for all configs have been updated.
- Throws:
ConfigInterruptedException
- if thread performing this call interrupted.SubscriberClosedException
- if subscriber is closed
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throwIfExceptionSet
protected void throwIfExceptionSet(ConfigSubscription<? extends com.yahoo.config.ConfigInstance> sub) If aConfigSubscription
has its exception set, reset that field and throw it- Parameters:
sub
-ConfigSubscription
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close
public void close()Closes all openConfigSubscription
s- Specified by:
close
in interfaceAutoCloseable
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toString
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startConfigThread
Convenience method to start a daemon thread called "Vespa config thread" with the given runnable. If you want the runnable to handle aConfigSubscriber
orConfigHandle
you have declared locally outside, declare them as final to make it work.- Parameters:
runnable
- a class implementingRunnable
- Returns:
- the newly started thread
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state
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reload
public void reload(long generation) Sets all subscriptions under this subscriber to have the given generation. This is intended for testing, to emulate a reload-config operation.- Parameters:
generation
- a generation number
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isClosed
public boolean isClosed() -
subscribe
public <T extends com.yahoo.config.ConfigInstance> ConfigHandle<T> subscribe(ConfigSubscriber.SingleSubscriber<T> singleSubscriber, Class<T> configClass, String configId) Convenience method that can be used if you only want to subscribe to one config, and want generic error handling. ImplementConfigSubscriber.SingleSubscriber
and pass it to this method. You will get initial config, and a config thread will be started. The method will throw in your thread if initial configuration fails, and the config thread will print a generic error message (but continue) if it fails thereafter. The config thread will stop if youclose()
thisConfigSubscriber
.- Type Parameters:
T
- ConfigInstance type- Parameters:
singleSubscriber
- The object to receive configconfigClass
- The class, typically generated from a def-file using config-class-pluginconfigId
- Identifies the service in vespa-services.xml- Returns:
- The handle of the config
- See Also:
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getGeneration
public long getGeneration()The current generation of configs known by this subscriber.- Returns:
- the current generation of configs known by this subscriber
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finalize
Finalizer to ensure that we do not leak resources on reconfig. Though finalizers are bad, this is not a performance critical object as it will be deconstructed typically container reconfig.
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