ratpack.consul.RatpackConsulConfig.java Source code

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Here is the source code for ratpack.consul.RatpackConsulConfig.java

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/*
 * Copyright 2016 the original author or authors.
 *
 * 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 ratpack.consul;

import com.google.common.io.ByteSource;
import com.orbitz.consul.Consul;
import com.orbitz.consul.option.QueryOptions;
import ratpack.func.Action;
import ratpack.util.Exceptions;

/**
 * Integration for retrieving values from a <a href=https://www.consul.io/>Consul</a> Key-Value store as {@link com.google.common.io.ByteSource} to be used
 * with the existing {@link ratpack.server.ServerConfigBuilder} parsing options.
 * @since 1.5
 */
public interface RatpackConsulConfig {

    /**
     * Read the specified key as a {@link ByteSource} using the default Consul agent connection properties.
     *
     * @param key the key to read from Consul's Key-Value store
     * @return a {@link ByteSource} representing the value stored in the key
     * @see #value(String, QueryOptions, Action)
     */
    static ByteSource value(String key) {
        return value(key, QueryOptions.BLANK, Action.noop());
    }

    /**
     * Read the specified key as a {@link ByteSource} using the default Consul agent connection properties and the provided {@link QueryOptions}.
     *
     * @param key the key to read from Consul Key-Value store
     * @param queryOptions the options to use when querying Consul
     * @return a {@link ByteSource} representing the value stored in the key
     * @see #value(String, QueryOptions, Action)
     */
    static ByteSource value(String key, QueryOptions queryOptions) {
        return value(key, queryOptions, Action.noop());
    }

    /**
     * Read the specified key as a {@link ByteSource} using the specified configuration to connection to Consul.
     *
     * @param key the key to read from Consul's KeyValue store
     * @param clientConfig the configuration for the Consul connection
     * @return a {@link ByteSource} representing the value stored in the key
     * @see #value(String, QueryOptions, Action)
     */
    static ByteSource value(String key, Action<? super Consul.Builder> clientConfig) {
        return value(key, QueryOptions.BLANK, clientConfig);
    }

    /**
     * Read the specified key as a {@link ByteSource} using the specified configuration to connection to Consul and the provided {@link QueryOptions}.
     * The returned value can then be passed to the existing parsing options in {@link ratpack.server.ServerConfigBuilder} to provide configuration.
     * <p>
     * <pre class="java-args">{@code
     * import ratpack.consul.RatpackConsulConfig;
     * import ratpack.test.embed.EmbeddedApp;
     * import com.orbitz.consul.option.ImmutableQueryOptions;
     *
     * public class Example {
     *   public static class Config {
     *     public String name;
     *     public String environment;
     *     public String secret;
     *   }
     *
     *   public static void main(String... args) throws Exception {
     *     EmbeddedApp.of(a -> a
     *       .serverConfig(s -> s
     *         .yaml(RatpackConsulConfig.value("default/app"))
     *         .json(RatpackConsulConfig.value("default/environment", ImmutableQueryOptions.builder().token("app-acl-token").build()))
     *         .props(RatpackConsulConfig.value("app/environment", b -> b.withUrl("https://consul.domain.io")))
     *         .require("/config", Config.class)
     *       )
     *       .handlers(c -> c
     *         .get(ctx -> ctx.render(ctx.get(Config.class)))
     *       )
     *     );
     *   }
     * }
     * }</pre>
     * @param key the key to read from Consul Key-Value store
     * @param queryOptions the options to use when querying Consul
     * @param clientConfig he configuration for the Consul connection
     * @return a {@link ByteSource} representing the value stored in the key
     */
    static ByteSource value(String key, QueryOptions queryOptions, Action<? super Consul.Builder> clientConfig) {
        return Exceptions.uncheck(() -> ByteSource.wrap(clientConfig.with(Consul.builder()).build().keyValueClient()
                .getValue(key, queryOptions).transform(v -> v.getValueAsString().or("")).or("").getBytes()));
    }

}