GH-2: Expose a @MessagingGateway for sftpConsumer

Fixes: #2

* To avoid `@Lazy` and other possible injection problems
when an `IntegrationFlow` is not ready yet, provide a `@MessagingGateway(name = "sftpConsumer")`
explicitly for the `MessageConsumer` in the `SftpConsumerConfiguration`

* Make SFTP modules as auto-configuration
* Fix Checkstyle violations in those modules

consumer/spring-sftp-consumer/README.adoc

@@ -4,7 +4,7 @@ A consumer that allows you to SFTP files.
 
 ## Beans for injection
 
-You can import `SftpConsumerConfiguration` in the application and then inject the following bean.
+The `SftpConsumerConfiguration` auto-configuration provides the following bean:
 
 `Consumer<Message<?>> sftpConsumer`
 

consumer/spring-sftp-consumer/src/main/java/org/springframework/cloud/fn/consumer/sftp/SftpConsumerConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2023 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -20,13 +20,13 @@
 
 import org.apache.sshd.sftp.client.SftpClient;
 
+import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.fn.common.config.ComponentCustomizer;
 import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.integration.annotation.MessagingGateway;
 import org.springframework.integration.dsl.IntegrationFlow;
-import org.springframework.integration.dsl.IntegrationFlowBuilder;
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.sftp.dsl.Sftp;
 import org.springframework.integration.sftp.dsl.SftpMessageHandlerSpec;
@@ -35,12 +35,12 @@
 import org.springframework.messaging.Message;
 
 /**
- * Configuration for SFTP Consumer.
+ * Auto-configuration for SFTP Consumer.
  *
  * @author Soby Chacko
  * @author Corneil du Plessis
  */
-@Configuration(proxyBeanMethods = false)
+@AutoConfiguration
 @EnableConfigurationProperties(SftpConsumerProperties.class)
 @Import(SftpConsumerSessionFactoryConfiguration.class)
 public class SftpConsumerConfiguration {
@@ -50,9 +50,6 @@ public IntegrationFlow ftpOutboundFlow(SftpConsumerProperties properties,
 			SessionFactory<SftpClient.DirEntry> ftpSessionFactory,
 			@Nullable ComponentCustomizer<SftpMessageHandlerSpec> sftpMessageHandlerSpecCustomizer) {
 
-		IntegrationFlowBuilder integrationFlowBuilder = IntegrationFlow.from(MessageConsumer.class,
-				(gateway) -> gateway.beanName("sftpConsumer"));
-
 		SftpMessageHandlerSpec handlerSpec = Sftp
 			.outboundAdapter(new SftpRemoteFileTemplate(ftpSessionFactory), properties.getMode())
 			.remoteDirectory(properties.getRemoteDir())
@@ -69,10 +66,11 @@ public IntegrationFlow ftpOutboundFlow(SftpConsumerProperties properties,
 			sftpMessageHandlerSpecCustomizer.customize(handlerSpec);
 		}
 
-		return integrationFlowBuilder.handle(handlerSpec).get();
+		return (flow) -> flow.handle(handlerSpec);
 	}
 
-	private interface MessageConsumer extends Consumer<Message<?>> {
+	@MessagingGateway(name = "sftpConsumer", defaultRequestChannel = "ftpOutboundFlow.input")
+	public interface MessageConsumer extends Consumer<Message<?>> {
 
 	}
 

consumer/spring-sftp-consumer/src/main/java/org/springframework/cloud/fn/consumer/sftp/SftpConsumerProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -27,6 +27,8 @@
 import org.springframework.validation.annotation.Validated;
 
 /**
+ * The configuration properties for SFTP consumer.
+ *
  * @author Gary Russell
  * @author Artem Bilan
  * @author Corneil du Plessis
@@ -122,7 +124,7 @@ public void setFilenameExpression(String filenameExpression) {
 
 	@NotBlank
 	public String getRemoteDir() {
-		return remoteDir;
+		return this.remoteDir;
 	}
 
 	public final void setRemoteDir(String remoteDir) {
@@ -131,7 +133,7 @@ public final void setRemoteDir(String remoteDir) {
 
 	@NotBlank
 	public String getTmpFileSuffix() {
-		return tmpFileSuffix;
+		return this.tmpFileSuffix;
 	}
 
 	public void setTmpFileSuffix(String tmpFileSuffix) {
@@ -140,7 +142,7 @@ public void setTmpFileSuffix(String tmpFileSuffix) {
 
 	@NotBlank
 	public String getRemoteFileSeparator() {
-		return remoteFileSeparator;
+		return this.remoteFileSeparator;
 	}
 
 	public void setRemoteFileSeparator(String remoteFileSeparator) {

consumer/spring-sftp-consumer/src/main/java/org/springframework/cloud/fn/consumer/sftp/SftpConsumerSessionFactoryConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2022 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -22,7 +22,7 @@
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.core.io.Resource;
-import org.springframework.integration.context.IntegrationContextUtils;
+import org.springframework.expression.Expression;
 import org.springframework.integration.file.remote.session.CachingSessionFactory;
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.sftp.session.DefaultSftpSessionFactory;
@@ -51,9 +51,9 @@ public SessionFactory<SftpClient.DirEntry> sftpSessionFactory(SftpConsumerProper
 		sftpSessionFactory.setPrivateKey(factory.getPrivateKey());
 		sftpSessionFactory.setPrivateKeyPassphrase(factory.getPassPhrase());
 		sftpSessionFactory.setAllowUnknownKeys(factory.isAllowUnknownKeys());
-		if (factory.getKnownHostsExpression() != null) {
-			String knownHostsLocation = factory.getKnownHostsExpression()
-				.getValue(IntegrationContextUtils.getEvaluationContext(applicationContext), String.class);
+		Expression knownHostsExpression = factory.getKnownHostsExpression();
+		if (knownHostsExpression != null) {
+			String knownHostsLocation = knownHostsExpression.getValue(String.class);
 			Resource knownHostsResource = applicationContext.getResource(knownHostsLocation);
 			sftpSessionFactory.setKnownHostsResource(knownHostsResource);
 		}

consumer/spring-sftp-consumer/src/main/java/org/springframework/cloud/fn/consumer/sftp/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * The SFTP consumer auto-configuration support.
+ */
+package org.springframework.cloud.fn.consumer.sftp;

consumer/spring-sftp-consumer/src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports

@@ -0,0 +1 @@
+org.springframework.cloud.fn.consumer.sftp.SftpConsumerConfiguration

consumer/spring-sftp-consumer/src/test/java/org/springframework/cloud/fn/consumer/sftp/SftpConsumerPropertiesTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2020 the original author or authors.
+ * Copyright 2015-2024 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.
@@ -20,26 +20,14 @@
 
 import org.junit.jupiter.api.Test;
 
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Qualifier;
-import org.springframework.boot.context.properties.ConfigurationPropertiesBinding;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.cloud.fn.common.config.SpelExpressionConverterConfiguration;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
-import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
-import org.springframework.context.annotation.Lazy;
-import org.springframework.core.convert.converter.Converter;
-import org.springframework.expression.EvaluationContext;
-import org.springframework.expression.Expression;
-import org.springframework.expression.ParseException;
-import org.springframework.expression.spel.standard.SpelExpression;
-import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.integration.config.EnableIntegration;
-import org.springframework.integration.config.IntegrationConverter;
-import org.springframework.integration.context.IntegrationContextUtils;
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.file.support.FileExistsMode;
 import org.springframework.integration.test.util.TestUtils;
@@ -160,50 +148,9 @@ static class Conf {
 	@Configuration
 	@EnableConfigurationProperties(SftpConsumerProperties.class)
 	@EnableIntegration
-	@Import(SftpConsumerSessionFactoryConfiguration.class)
+	@Import({ SpelExpressionConverterConfiguration.class, SftpConsumerSessionFactoryConfiguration.class })
 	static class Factory {
 
-		@Bean
-		@ConfigurationPropertiesBinding
-		@IntegrationConverter
-		public Converter<String, Expression> spelConverter() {
-			return new SpelConverter();
-		}
-
-		/**
-		 * TODO: This needs to be refactored into a generic place for any functions to
-		 * use.
-		 *
-		 * A simple converter from String to Expression.
-		 *
-		 * @author Eric Bottard
-		 */
-		public static class SpelConverter implements Converter<String, Expression> {
-
-			private SpelExpressionParser parser = new SpelExpressionParser();
-
-			@Autowired
-			@Qualifier(IntegrationContextUtils.INTEGRATION_EVALUATION_CONTEXT_BEAN_NAME)
-			@Lazy
-			private EvaluationContext evaluationContext;
-
-			@Override
-			public Expression convert(String source) {
-				try {
-					Expression expression = this.parser.parseExpression(source);
-					if (expression instanceof SpelExpression) {
-						((SpelExpression) expression).setEvaluationContext(this.evaluationContext);
-					}
-					return expression;
-				}
-				catch (ParseException e) {
-					throw new IllegalArgumentException(
-							String.format("Could not convert '%s' into a SpEL expression", source), e);
-				}
-			}
-
-		}
-
 	}
 
 }

supplier/spring-sftp-supplier/README.adoc

@@ -25,7 +25,7 @@ When configuring the `sftp.factory.known-hosts-expression` option, the root obje
 
 ## Idempotency
 
-By default the supplier uses a https://docs.spring.io/spring-integration/api/org/springframework/integration/metadata/SimpleMetadataStore.html[SimpleMetadataStore], storing the last modified time to track files that have already been processed in memory.
+By default, the supplier uses a https://docs.spring.io/spring-integration/api/org/springframework/integration/metadata/SimpleMetadataStore.html[SimpleMetadataStore], storing the last modified time to track files that have already been processed in memory.
 If an application using this supplier is restarted, any existing files will be reprocessed. You can inject on of the persistent https://docs.spring.io/spring-integration/reference/html/meta-data-store.html[MetadataStore implementations] provided by Spring Integration, or your own of course, to maintain this state permanently.
 See also link:../../common/metadata-store-common/README.adoc[`MetadataStore`] options for possible shared persistent store configuration for the `SftpPersistentAcceptOnceFileListFilter` used in the SFTP Source.
 
@@ -60,7 +60,7 @@ Users have to subscribe to this `Flux` and receive the data.
 
 ## Beans for injection
 
-You can import the `SftpSupplierConfiguration` in the application and then inject the following bean.
+The `SftpSupplierConfiguration` auto-configuration provides the following bean:
 
 `sftpSupplier`
 
@@ -76,7 +76,7 @@ All configuration properties are prefixed with `sftp.supplier`.
 There are also properties that need to be used with the prefix `file.consumer`.
 
 For more information on the various options available, please see link:src/main/java/org/springframework/cloud/fn/supplier/sftp/SftpSupplierProperties.java[SftpSupplierProperties].
-Also see link:src/main/java/org/springframework/cloud/fn/supplier/file/FileConsumerProperties.java[FileConsumerProperties].
+Also see `FileConsumerProperties`.
 
 ## Examples