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https://issues.apache.org/jira/browse/CURATOR-457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16382146#comment-16382146
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Aleksander Melnichnikov commented on CURATOR-457:
-------------------------------------------------
[~randgalt] The use-case:
supply different service registration politics. They can be different in
different teams or companies. In our company we have another path pattern rules
and we can't change our path patterns to Curator's one, and also it's hard to
extend the current code because of high encapsulation, the trivial
customization forces to rewrite a lot of Curator's classes.
> Configuring service discovery paths
> -----------------------------------
>
> Key: CURATOR-457
> URL: https://issues.apache.org/jira/browse/CURATOR-457
> Project: Apache Curator
> Issue Type: Improvement
> Reporter: Aleksander Melnichnikov
> Assignee: Jordan Zimmerman
> Priority: Minor
>
> Right now paths for services in service discovery hardcoded to pattern:
> */\{basePath} /\{serviceName}/\{instanceId}.* And that's impossible to
> configure paths this way: */\{basePathPart1}
> /\{serviceName}/\{basePathPart2}/\{instanceId}*
> For example:
> If basePath = */base1/base2/base3*, serviceName = *serviceName*, instanceId
> - *serviceId*
> then path will be
> */**base1**/**base2**/**base3**/**serviceName**/**serviceId*, that can't be
> configured like this:
> */**base1**/**base2/serviceName**/**base3**/**serviceId.*
> Because of strong encapsulation in ServiceDiscoveryImpl class (package
> private method modifiers)
> {code:java}
> @VisibleForTesting
> String pathForName(String name)
> {
> return ZKPaths.makePath(basePath, name);
> }
> @VisibleForTesting
> String pathForInstance(String name, String id)
> {
> return ZKPaths.makePath(pathForName(name), id);
> }
> {code}
> So, can we rethink visibility modifiers or add some extendable entity which
> would be responsible for constructing paths?
> For example:
> Create interface
> {code:java}
> /**
> * A constructor which constructs path to services for service discovering
> */
> public interface DiscoveryPathConstructor
> {
> /**
> * Return the path where all service names registered
> * @return basePath
> */
> String getBasePath();
> /**
> * Return the path where all instances of service registered
> * @param name service name
> * @return path to service instances
> */
> String getPathForInstances(String name);
> /**
> * Return the path where concrete instance registered
> * @param name service name
> * @param id concrete instance id
> * @return path to concrete instance
> */
> String getPathForInstance(String name, String id);
> }
> {code}
> Also make a constructor and field in ServiceDiscoveryImpl:
> {code:java}
> private final DiscoveryPathConstructor pathConstructor;
> /**
> * @param client the client
> * @param pathConstructor constructor for instances path
> * @param serializer serializer for instances (e.g. {@link
> JsonInstanceSerializer})
> * @param thisInstance instance that represents the service that is
> running. The instance will get auto-registered
> * @param watchInstances if true, watches for changes to locally
> registered instances
> */
> public ServiceDiscoveryImpl(CuratorFramework client,
> DiscoveryPathConstructor pathConstructor, InstanceSerializer<T> serializer,
> ServiceInstance<T> thisInstance, boolean
> watchInstances)
> {
> this.watchInstances = watchInstances;
> this.client = Preconditions.checkNotNull(client, "client cannot be
> null");
> this.serializer = Preconditions.checkNotNull(serializer, "serializer
> cannot be null");
> this.pathConstructor = Preconditions.checkNotNull(pathConstructor,
> "pathConstructor cannot be null");
> if ( thisInstance != null )
> {
> Entry<T> entry = new Entry<T>(thisInstance);
> entry.cache = makeNodeCache(thisInstance);
> services.put(thisInstance.getId(), entry);
> }
> }
> {code}
> You can view commit in my fork of framework, if that's ok - I can make a pull
> request.
> https://github.com/Me1kaa/curator/commit/6e6a34db7d71a84e3a53d284fc94e1fe2e3c10d8
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