Move NamedChannel model to core module (#89)

This commit introduces the NamedChannelRegistry which allows
moving the NamedChannel model to the core package and decouples
it from the client properties.

spring-grpc-core/src/main/java/org/springframework/grpc/client/NamedChannel.java

@@ -0,0 +1,348 @@
+/*
+ * Copyright 2023-2024 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
+ *
+ *      https://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 org.springframework.grpc.client;
+
+import java.time.Duration;
+import java.util.function.Consumer;
+
+import org.springframework.util.unit.DataSize;
+
+import io.grpc.ManagedChannel;
+
+/**
+ * Represents the configuration for a {@link ManagedChannel gRPC channel}.
+ *
+ * @author Chris Bono
+ */
+public class NamedChannel {
+
+	/**
+	 * The target address uri to connect to.
+	 */
+	private String address = "static://localhost:9090";
+
+	public String getAddress() {
+		return this.address;
+	}
+
+	public void setAddress(final String address) {
+		this.address = address;
+	}
+
+	// --------------------------------------------------
+	// defaultLoadBalancingPolicy
+	// --------------------------------------------------
+
+	/**
+	 * The default load balancing policy the channel should use.
+	 */
+	private String defaultLoadBalancingPolicy = "round_robin";
+
+	public String getDefaultLoadBalancingPolicy() {
+		return this.defaultLoadBalancingPolicy;
+	}
+
+	public void setDefaultLoadBalancingPolicy(final String defaultLoadBalancingPolicy) {
+		this.defaultLoadBalancingPolicy = defaultLoadBalancingPolicy;
+	}
+
+	// --------------------------------------------------
+
+	private final Health health = new Health();
+
+	public Health getHealth() {
+		return this.health;
+	}
+
+	/**
+	 * The negotiation type for the channel.
+	 */
+	private NegotiationType negotiationType = NegotiationType.PLAINTEXT;
+
+	public NegotiationType getNegotiationType() {
+		return this.negotiationType;
+	}
+
+	public void setNegotiationType(NegotiationType negotiationType) {
+		this.negotiationType = negotiationType;
+	}
+
+	// --------------------------------------------------
+	// KeepAlive
+	// --------------------------------------------------
+
+	/**
+	 * Whether keep alive is enabled on the channel.
+	 */
+	private boolean enableKeepAlive = false;
+
+	public boolean isEnableKeepAlive() {
+		return this.enableKeepAlive;
+	}
+
+	public void setEnableKeepAlive(boolean enableKeepAlive) {
+		this.enableKeepAlive = enableKeepAlive;
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * The duration without ongoing RPCs before going to idle mode.
+	 */
+	private Duration idleTimeout = Duration.ofSeconds(20);
+
+	public Duration getIdleTimeout() {
+		return this.idleTimeout;
+	}
+
+	public void setIdleTimeout(Duration idleTimeout) {
+		this.idleTimeout = idleTimeout;
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * The delay before sending a keepAlive. Note that shorter intervals increase the
+	 * network burden for the server and this value can not be lower than
+	 * 'permitKeepAliveTime' on the server.
+	 */
+	private Duration keepAliveTime = Duration.ofMinutes(5);
+
+	public Duration getKeepAliveTime() {
+		return this.keepAliveTime;
+	}
+
+	public void setKeepAliveTime(Duration keepAliveTime) {
+		this.keepAliveTime = keepAliveTime;
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * The default timeout for a keepAlives ping request.
+	 */
+	private Duration keepAliveTimeout = Duration.ofSeconds(20);
+
+	public Duration getKeepAliveTimeout() {
+		return this.keepAliveTimeout;
+	}
+
+	public void setKeepAliveTimeout(Duration keepAliveTimeout) {
+		this.keepAliveTimeout = keepAliveTimeout;
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * Whether a keepAlive will be performed when there are no outstanding RPC on a
+	 * connection.
+	 */
+	private boolean keepAliveWithoutCalls = false;
+
+	public boolean isKeepAliveWithoutCalls() {
+		return this.keepAliveWithoutCalls;
+	}
+
+	public void setKeepAliveWithoutCalls(boolean keepAliveWithoutCalls) {
+		this.keepAliveWithoutCalls = keepAliveWithoutCalls;
+	}
+
+	// --------------------------------------------------
+	// Message Transfer
+	// --------------------------------------------------
+
+	/**
+	 * Maximum message size allowed to be received by the channel (default 4MiB). Set to
+	 * '-1' to use the highest possible limit (not recommended).
+	 */
+	private DataSize maxInboundMessageSize = DataSize.ofBytes(4194304);
+
+	/**
+	 * Maximum metadata size allowed to be received by the channel (default 8KiB). Set to
+	 * '-1' to use the highest possible limit (not recommended).
+	 */
+	private DataSize maxInboundMetadataSize = DataSize.ofBytes(8192);
+
+	public DataSize getMaxInboundMessageSize() {
+		return this.maxInboundMessageSize;
+	}
+
+	public void setMaxInboundMessageSize(final DataSize maxInboundMessageSize) {
+		this.setMaxInboundSize(maxInboundMessageSize, (s) -> this.maxInboundMessageSize = s, "maxInboundMesssageSize");
+	}
+
+	public DataSize getMaxInboundMetadataSize() {
+		return this.maxInboundMetadataSize;
+	}
+
+	public void setMaxInboundMetadataSize(DataSize maxInboundMetadataSize) {
+		this.setMaxInboundSize(maxInboundMetadataSize, (s) -> this.maxInboundMetadataSize = s,
+				"maxInboundMetadataSize");
+	}
+
+	private void setMaxInboundSize(DataSize maxSize, Consumer<DataSize> setter, String propertyName) {
+		if (maxSize != null && maxSize.toBytes() >= 0) {
+			setter.accept(maxSize);
+		}
+		else if (maxSize != null && maxSize.toBytes() == -1) {
+			setter.accept(DataSize.ofBytes(Integer.MAX_VALUE));
+		}
+		else {
+			throw new IllegalArgumentException("Unsupported %s: %s".formatted(propertyName, maxSize));
+		}
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * The custom User-Agent for the channel.
+	 */
+	private String userAgent = null;
+
+	public String getUserAgent() {
+		return this.userAgent;
+	}
+
+	public void setUserAgent(final String userAgent) {
+		this.userAgent = userAgent;
+	}
+
+	/**
+	 * Provide a copy of the channel instance.
+	 * @return a copy of the channel instance.
+	 */
+	public NamedChannel copy() {
+		NamedChannel copy = new NamedChannel();
+		copy.address = this.address;
+		copy.defaultLoadBalancingPolicy = this.defaultLoadBalancingPolicy;
+		copy.negotiationType = this.negotiationType;
+		copy.enableKeepAlive = this.enableKeepAlive;
+		copy.idleTimeout = this.idleTimeout;
+		copy.keepAliveTime = this.keepAliveTime;
+		copy.keepAliveTimeout = this.keepAliveTimeout;
+		copy.keepAliveWithoutCalls = this.keepAliveWithoutCalls;
+		copy.maxInboundMessageSize = this.maxInboundMessageSize;
+		copy.maxInboundMetadataSize = this.maxInboundMetadataSize;
+		copy.userAgent = this.userAgent;
+		copy.health.copyValuesFrom(this.getHealth());
+		copy.ssl.copyValuesFrom(this.getSsl());
+		return copy;
+	}
+
+	// --------------------------------------------------
+
+	/**
+	 * Flag to say that strict SSL checks are not enabled (so the remote certificate could
+	 * be anonymous).
+	 */
+	private boolean secure = true;
+
+	public boolean isSecure() {
+		return this.secure;
+	}
+
+	public void setSecure(boolean secure) {
+		this.secure = secure;
+	}
+
+	// --------------------------------------------------
+
+	private final Ssl ssl = new Ssl();
+
+	public Ssl getSsl() {
+		return this.ssl;
+	}
+
+	public static class Ssl {
+
+		/**
+		 * Whether to enable SSL support. Enabled automatically if "bundle" is provided
+		 * unless specified otherwise.
+		 */
+		private Boolean enabled;
+
+		/**
+		 * SSL bundle name.
+		 */
+		private String bundle;
+
+		public boolean isEnabled() {
+			return (this.enabled != null) ? this.enabled : this.bundle != null;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+
+		public String getBundle() {
+			return this.bundle;
+		}
+
+		public void setBundle(String bundle) {
+			this.bundle = bundle;
+		}
+
+		/**
+		 * Copies the values from another instance.
+		 * @param other instance to copy values from
+		 */
+		public void copyValuesFrom(Ssl other) {
+			this.enabled = other.enabled;
+			this.bundle = other.bundle;
+		}
+
+	}
+
+	public static class Health {
+
+		/**
+		 * Whether to enable client-side health check for the channel.
+		 */
+		private boolean enabled = false;
+
+		/**
+		 * Name of the service to check health on.
+		 */
+		private String serviceName;
+
+		public boolean isEnabled() {
+			return this.enabled;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+
+		public String getServiceName() {
+			return this.serviceName;
+		}
+
+		public void setServiceName(String serviceName) {
+			this.serviceName = serviceName;
+		}
+
+		/**
+		 * Copies the values from another instance.
+		 * @param other instance to copy values from
+		 */
+		public void copyValuesFrom(Health other) {
+			this.enabled = other.enabled;
+			this.serviceName = other.serviceName;
+		}
+
+	}
+
+}