THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Move membership code to a separate gradle sub-project
To be Reviewed By: 9/6/2019
Authors: Dan Smith, Bruce Schuchardt
Status: Discussion Development
Superseded by: N/A
Related: N/A
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| PlantUML |
|---|
@startuml "geode-core" --> geode-membership "geode-core" --> geode-serialization "geode-core" --> geode-tcp-server "geode-membership" --> geode-serialization "geode-membership" --> geode-tcp-server "geode-tcp-server" --> geode-serialization @enduml |
Breaking circular dependencies
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- Move the dependencies to a separate subproject - serialization is and tcp-server (Locator infrastructure) are moving to separate subproject subprojects so that membership can depend directly on thatthem
- Inject dependencies at runtime - dependencies such as gemfire stats can be injected into the membership system by providing interfaces such as MembershipStatistics (see below) that geode core must provide when creating the membership system.
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| PlantUML |
|---|
@startuml
interface MembershipBuilder {
+ static newMembershipBuilder()
----
+ set...()
}
interface Membership {
Core class of a running membership system.
+ getMembershipView(): MembershipView
}
interface Messenger {
+ send(Message)
}
interface MembershipView {
+ getMembers(): List<MemberID>List<MemberIdentifier>
}
interface MemberIDMemberIdentifier {
A single member of the system
}
interface MembershipListener {
}
interface MessageHandler {
}
interface Authenticator {
}
interface MembershipStatistics {
}
interface Config {
}
interface MembershipView {
}
MembershipBuilder --> Membership : creates
MembershipBuilder *-- Authenticator
MembershipBuilder *-- MembershipStatistics
MembershipBuilder *-- MessageHandler
MembershipBuilder *-- Config
MembershipBuilder *-- MembershipListener
Membership *-- Messenger
Membership *-- MembershipView
MembershipView *-- MemberIDMemberIdentifier
@enduml
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| Code Block | ||
|---|---|---|
| ||
/**
* Creates the membership system, given the provided configuration
*/
interface MembershipBuilder {
static MembershipBuilder newMembershipBuilder()
MembershipBuilder setConfig(Config)
MembershipBuilder setAuthenticator(Authenticator)
MembershipBuilder setMembershipListener(MembershipListener)
MembershipBuilder setMessageHandler(MessageHandler)
MembershipBuilder setMembershipStatistics(MembershipStatistics)
MembershipBuilder setMemberFactorysetMemberIDFactory(MemberIDFactoryMemberIdentifierFactory)
create() : Membership
}
/**
* Core class of a running membership system.
*/
interface Membership {
getMembershipView(): MembershipView
getMessenger(): Messenger
getLocalMember(): MemberIDMemberIdentifier
contactedBy(MemberIDMemberIdentifier)
isShunned(MemberIDMemberIdentifier)
close()
isClosed()
}
/**
* API for sending messages to other members, using memberships messaging system
* Membership currently allows geode-core to send messages over it's UDP messaging system.
* This interface provides that functionality.
*/
interface Messenger {
send(Message)
/** Get an object the represents what messages have been sent to to the given
* memberIDMemberIdentifier. This is used in waitForMessengerState to wait for these messages
* to arrive on the remote side
*/
getMessengerState(MemberIDMemberIdentifer): MessengerState
waitForMessengerState(MessengerState)
}
/**
* A Message that will be sent to the returned recipients.
*/
interface Message {
Set<MemberID>List<MemberIdentifier> getRecipients()
}
/**
* An object which represents the state of the sending side of a communication
* channel at a point in time. This object can be passed to the waitForMessengerState
* method on the receiving side to ensure all messages have been received on
* the receiving side
*/
interface MessengerState extends DataSerializableFixedID {
}/**
* Interface used to create a MemberIDMemberIdentifier from a set of properties
* This API is provided solely to allow geode-core to add additional
* properties to the MemberIDMemberIdentifier that are not relevant to membership
* For example DurableClientAttributes. Membership will provide
* A default MemberIDMemberIdentifier which just has the membership relevant attributes
*/
interface MemberIDFactoryMemberIdentifierFactory {
MemberIDMemberIdentifier create(host, port, uuid, ...memberData)
}
/**
* A single member of the system. In practice, this will
* be implemented by InternalDistributedMember
*/
interface MemberIDMemberIdentifier {
}
/**
* Provides the current members of the system
*/
interface MembershipView {
List<MemberID>List<MemberIdentifier> getMembers()
}
/**
* Receives notifications about changes to membership
*/
interface MembershipListener {
memberJoined(MemberIDMemberIdentifier)
memberDeparted(MemberIDMemberIdentifier)
memberCrashed(MemberIDMemberIdentifier)
forceDisconnected(String reason)
}
/**
* Receives all messages sent from other members
*/
interface MessageHandler {
processMessage(Message)
}
/**
* Interface used by membership to authenticate other members
*/
interface Authenticator {
/**
* Authenticate peer member
*
* @return null if authentication succeed (including no authenticator case), otherwise, return
* failure message
*/
String authenticate(MemberIDMemberIdentifier member, Properties credentials);
/**
* Get credential object for the given GemFire distributed member.
*/
Properties getCredentials(MemberIDMemberIdentifier member);
}
/**
* Interface to notify statistics systems about membership changes
*/
interface MembershipStatistics {
memberJoined()
memberDeparted()
...
}
/**
* Primitive configuration options for membership
* - timeouts, etc.
*/
interface Config {
getJoinTimeout()
...
}
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| Code Block | ||
|---|---|---|
| ||
/** Use DSFIDSerializerFactory to create a serializer */
class DSFIDSerializerFactory {
/** set an ObjectSerializer that should be used when invoking
* toData/fromData methods on objects. This will typically
* defer serialization of DataSerializableFixedID objects to
* the DSFIDSerializer
*/
DSFIDSerializerFactory setObjectSerializer(ObjectSerializer serializer);
DSFIDSerializerFactory setObjectDeserializer(ObjectDeserializer deserializer);
DSFIDSerializer create();
}
/** writes and reads DataSerializableFixedID instances. Supports reading/writing of nulls */
interface DSFIDSerializer {
/** retrieve the ObjectSerializer. If none was given to the factory this will be
* a default serializer that can only handle DataSerializableFixedID objects */
ObjectSerializer getObjectSerializer();
ObjectDeserializer getObjectDeserializer();
/** register a class with the serializer. It must have a no-arg constructor */
void registerDSFID(int dsfid, Class dsfidClass);
SerializationContext createSerializationContext(DataOutput dataOutput);
DeserializationContext createDeserializationContext(DataInput dataInput);
void writeDSFID(DataSerializableFixedID o, int dsfid, DataOutput out) throws IOException;
void writeDSFID(DataSerializableFixedID dsfid, DataOutput out) throws IOException;
/** write a DataSerializableFixedID to the given DataOutput. This method should be used
* by extensions to DSFIDSerializer, like InternalDataSerializer, that want to handle
* more types in ObjectSerializer but defer DSFID serialization to the
* default implementation */
void writeDSFID(DataSerializableFixedID o, int dsfid, DataOutput out) throws IOException;
/** read a DataSerializableFixedID from the given DataInput. This method uses constructors
* registered via registerDSFID() and should be used by extensions to DSFIDSerializer,
* like InternalDataSerializer, that want to handle more types in ObjectDeserializer but
* defer DSFID serialization to the default implementation */
Object create(int dsfid, DataInput in) throws IOException, ClassNotFoundException;
void invokeToData(Object ds, DataOutput out) throws IOException;
void invokeFromData(Object ds, DataInput in) throws IOException, ClassNotFoundException;
int readDSFIDHeader(DataInput dis) throws IOException;
void writeDSFIDHeader(int dsfid, DataOutput out) throws IOException;
}
/** provides context for toData serialization methods */
interface SerializationContext {
ObjectSerializer getSerializer();
Version getSerializationVersion();
}
/** provides context for toData serialization methods */
interface DeserializationContext {
ObjectDeserializer getDeserializer();
Version getSerializationVersion();
}
interface ObjectSerializer {
public void writeObject(Object obj, DataOutput output) throws IOException;
void invokeToData(Object ds, DataOutput out) throws IOException;
...
}
interface ObjectDeserializer {
public Object readObject(DataInput input) throws IOException, ClassNotFoundException;
void invokeFromData(Object ds, DataInput in) throws IOException, ClassNotFoundException;
...
}
/** a new superclass of HeapDataOutputStream that separates the methods used with Buffers from
a bunch of other methods concerning other functionality such as Streamables, PDX, etc. */
class BufferDataOutputStream implements DataOutputStream {
// methods moved from HeapDataOutputStream unchanged
}
/** DataSerializableFixedID is modified to have more parameters in toData/fromData methods */
interface DataSerializableFixedID {
public Version[] getSerializationVersions();
public int getDSFID();
public void toData(DataOutput output, SerializationContext context) throws IOException;
public void fromData(DataInput input, DeserializationContext context) throws ClassNotFoundException, IOException;
}
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While serialization of primitives and Strings can be performed using DataInput and DataOutput there are a number of static serialization methods currently in geode-core that will have to be shifted into the DSFIDSerializer (writeString/readString, writeHashmap/readHashmap, etc) to maintain compatibility with past releases. Those methods shifted from DataSerializer will remain available in that class since it is a public API. The intent is to shift these methods further into the ObjectSerializer/ObjectDeserializer APIs and stop using static serialization methods.
Since Version is being repackaged any rolling-upgrade test code that refers to it will no longer work when running with an older version of Geode. We will provide methods in the distributed test framework VersionManager to make this less painful. We will replace the use of Version.CURRENT_ORDINAL with VersionManager.getInstance().getCurrentVersionOrdinal() in these tests. Other methods will be added to VersionManager as needed.
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