io.helidon.config.etcd.EtcdConfigSourceBuilder Maven / Gradle / Ivy
/*
* Copyright (c) 2017, 2021 Oracle and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.helidon.config.etcd;
import java.net.URI;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import io.helidon.common.Builder;
import io.helidon.config.AbstractConfigSourceBuilder;
import io.helidon.config.Config;
import io.helidon.config.etcd.EtcdConfigSourceBuilder.EtcdEndpoint;
import io.helidon.config.etcd.internal.client.EtcdClientFactory;
import io.helidon.config.etcd.internal.client.v2.EtcdV2ClientFactory;
import io.helidon.config.etcd.internal.client.v3.EtcdV3ClientFactory;
import io.helidon.config.spi.ChangeWatcher;
import io.helidon.config.spi.ConfigParser;
import io.helidon.config.spi.ParsableSource;
import io.helidon.config.spi.PollableSource;
import io.helidon.config.spi.PollingStrategy;
import io.helidon.config.spi.WatchableSource;
/**
* Etcd ConfigSource builder.
*
* It allows to configure following properties:
*
* - {@code uri} - etcd endpoint
* - {@code key} - an etcd key that is associated to value with configuration
* - {@code version} - an etcd API version
* - {@code mandatory} - is existence of configuration resource mandatory (by default) or is {@code optional}?
* - {@code media-type} - configuration content media type to be used to look for appropriate {@link ConfigParser};
* - {@code parser} - or directly set {@link ConfigParser} instance to be used to parse the source;
*
*
* One of {@code media-type} and {@code parser} properties must be set to be clear how to parse the content. If both of them
* are set, then {@code parser} has precedence.
*/
public final class EtcdConfigSourceBuilder extends AbstractConfigSourceBuilder
implements PollableSource.Builder,
WatchableSource.Builder,
ParsableSource.Builder,
Builder {
/**
* Default Etcd API version ({@link io.helidon.config.etcd.EtcdConfigSourceBuilder.EtcdApi#v2}).
*/
public static final EtcdApi DEFAULT_VERSION = EtcdApi.v2;
/**
* Default Etcd endpoint ({@code http://localhost:2379}).
*/
public static final URI DEFAULT_URI = URI.create("http://localhost:2379");
private static final String URI_KEY = "uri";
private static final String KEY_KEY = "key";
private static final String API_KEY = "api";
private List etcdEndpoints;
private URI[] uris = {DEFAULT_URI};
private String key;
private EtcdApi version = DEFAULT_VERSION;
EtcdConfigSourceBuilder() {
}
/**
* Builds new instance of Etcd ConfigSource.
*
* @return new instance of Etcd ConfigSource.
*/
@Override
public EtcdConfigSource build() {
// ensure endpoint is configured
target();
return new EtcdConfigSource(this);
}
/**
* {@inheritDoc}
*
* - {@code uri} - type {@link URI} - Etcd instance remote URI
* - {@code key} - type {@code String} - Etcd key the configuration is associated with
* - {@code api} - type {@link EtcdApi} - Etcd API version such as {@code v3}
*
* Optional {@code properties}: see {@link #config(Config)}.
*
* @param metaConfig meta-configuration used to update the builder instance from
* @return updated builder instance
* @see #config(Config)
*/
@Override
public EtcdConfigSourceBuilder config(Config metaConfig) {
metaConfig.get(URI_KEY).as(URI.class).ifPresent(this::uri);
metaConfig.get(KEY_KEY).asString().ifPresent(this::key);
metaConfig.get(API_KEY).asString().as(EtcdApi::valueOf).ifPresent(this::api);
return super.config(metaConfig);
}
@Override
public EtcdConfigSourceBuilder parser(ConfigParser parser) {
return super.parser(parser);
}
@Override
public EtcdConfigSourceBuilder mediaType(String mediaType) {
return super.mediaType(mediaType);
}
@Override
public EtcdConfigSourceBuilder pollingStrategy(PollingStrategy pollingStrategy) {
return super.pollingStrategy(pollingStrategy);
}
@Override
public EtcdConfigSourceBuilder changeWatcher(ChangeWatcher changeWatcher) {
return super.changeWatcher(changeWatcher);
}
/**
* Etcd endpoint remote URI.
*
* @param uris endpoint URIs
* @return updated builder instance
*/
public EtcdConfigSourceBuilder uri(URI... uris) {
this.uris = uris;
return this;
}
/**
* Etcd key with which the value containing the configuration is associated.
*
* @param key key
* @return updated builder instance
*/
public EtcdConfigSourceBuilder key(String key) {
this.key = key;
return this;
}
/**
* Etcd API version.
*
* @param version version, defaults to {@link EtcdApi#v3}
* @return updated builder instance
*/
public EtcdConfigSourceBuilder api(EtcdApi version) {
this.version = version;
return this;
}
List target() {
if (null == etcdEndpoints) {
if (null == uris || uris.length == 0) {
throw new IllegalArgumentException("etcd URI must be defined");
}
if (null == key) {
throw new IllegalArgumentException("etcd key must be defined");
}
if (null == version) {
throw new IllegalArgumentException("etcd api (version) must be defined");
}
// Key and version are shared by all endpoints
etcdEndpoints = Arrays.stream(uris)
.map(uri -> new EtcdEndpoint(uri, key, version))
.collect(Collectors.toList());
}
return etcdEndpoints;
}
EtcdEndpoint target(int k) {
return target().get(k);
}
/**
* {@code EtcdApi} determines which etcd API version will be used.
*
* There are two API versions: {@code v2} and {@code v3}.
*/
public enum EtcdApi {
/**
* Etcd API v2 version.
*/
v2(new EtcdV2ClientFactory()),
/**
* Etcd API v3 version.
*/
v3(new EtcdV3ClientFactory());
private final EtcdClientFactory clientFactory;
EtcdApi(EtcdClientFactory clientFactory) {
this.clientFactory = clientFactory;
}
/**
* The client factory for this version of etcd.
* @return client factory
*/
EtcdClientFactory clientFactory() {
return clientFactory;
}
}
/**
* Etcd endpoint remote descriptor.
*
* Holds attributes necessary to connect to remote Etcd service.
*/
public static class EtcdEndpoint {
private final URI uri;
private final String key;
private final EtcdApi api;
/**
* Initializes descriptor.
*
* @param uri an Etcd endpoint remote URI.
* @param key an Etcd key with which the value containing the configuration is associated.
* @param api an Etcd API version.
*/
public EtcdEndpoint(URI uri, String key, EtcdApi api) {
this.uri = uri;
this.key = key;
this.api = api;
}
/**
* Etcd endpoint remote URI.
*
* @return endpoint URI
*/
public URI uri() {
return uri;
}
/**
* Etcd key.
*
* @return key with configuration
*/
public String key() {
return key;
}
/**
* Etcd API version.
*
* @return API version
*/
public EtcdApi api() {
return api;
}
}
}