AWS Lambda Starter & Consistency Models

spring-boot-starter-aws-lambda/src/main/java/amazon/aws/AWSLambdaConfigurerAdapter.java

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+package amazon.aws;
+
+import com.amazonaws.auth.*;
+import com.amazonaws.services.lambda.AWSLambdaClientBuilder;
+import com.amazonaws.services.lambda.invoke.LambdaInvokerFactory;
+import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient;
+import com.amazonaws.services.securitytoken.model.Credentials;
+import com.amazonaws.services.securitytoken.model.GetSessionTokenRequest;
+import org.springframework.stereotype.Component;
+
+import java.util.Date;
+
+/**
+ * This class is a client for interacting with Amazon S3 bucket resources.
+ *
+ * @author kbastani
+ */
+@Component
+public class AWSLambdaConfigurerAdapter {
+
+    private String accessKeyId;
+    private String accessKeySecret;
+    private Credentials sessionCredentials;
+
+    /**
+     * Create a new instance of the {@link AWSLambdaConfigurerAdapter} with the bucket name and access credentials
+     *
+     * @param accessKeyId     is the access key id credential for the specified bucket name
+     * @param accessKeySecret is the access key secret for the specified bucket name
+     */
+    public AWSLambdaConfigurerAdapter(String accessKeyId,
+                                      String accessKeySecret) {
+        this.accessKeyId = accessKeyId;
+        this.accessKeySecret = accessKeySecret;
+    }
+
+    /**
+     * Gets an instance of a function interface
+     * @param type
+     * @param <T>
+     * @return
+     */
+    public <T> T getFunctionInstance(Class<T> type) {
+        return LambdaInvokerFactory.builder()
+                .lambdaClient(AWSLambdaClientBuilder.standard()
+                        .withCredentials(new AWSStaticCredentialsProvider(
+                                getBasicSessionCredentials()))
+                        .build())
+                .build(type);
+    }
+
+    /**
+     * Get the basic session credentials for the template's configured IAM authentication keys
+     *
+     * @return a {@link BasicSessionCredentials} instance with a valid authenticated session token
+     */
+    private BasicSessionCredentials getBasicSessionCredentials() {
+
+        // Create a new session token if the session is expired or not initialized
+        if (sessionCredentials == null || sessionCredentials.getExpiration().before(new Date()))
+            sessionCredentials = getSessionCredentials();
+
+        // Create basic session credentials using the generated session token
+        return new BasicSessionCredentials(sessionCredentials.getAccessKeyId(),
+                sessionCredentials.getSecretAccessKey(),
+                sessionCredentials.getSessionToken());
+    }
+
+    /**
+     * Creates a new session credential that is valid for 12 hours
+     *
+     * @return an authenticated {@link Credentials} for the new session token
+     */
+    private Credentials getSessionCredentials() {
+        // Create a new session with the user credentials for the service instance
+        AWSSecurityTokenServiceClient stsClient =
+                new AWSSecurityTokenServiceClient(new BasicAWSCredentials(accessKeyId, accessKeySecret));
+
+        // Start a new session for managing a service instance's bucket
+        GetSessionTokenRequest getSessionTokenRequest =
+                new GetSessionTokenRequest().withDurationSeconds(43200);
+
+        // Get the session token for the service instance's bucket
+        sessionCredentials = stsClient.getSessionToken(getSessionTokenRequest).getCredentials();
+
+        return sessionCredentials;
+    }
+}

spring-boot-starter-aws-lambda/src/main/java/amazon/aws/AmazonAutoConfiguration.java

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+package amazon.aws;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * This class auto-configures a {@link AWSLambdaConfigurerAdapter} bean.
+ *
+ * @author kbastani
+ */
+@Configuration
+@ConditionalOnMissingBean(AWSLambdaConfigurerAdapter.class)
+@EnableConfigurationProperties(AmazonProperties.class)
+public class AmazonAutoConfiguration {
+
+    @Autowired
+    private AmazonProperties amazonProperties;
+
+    @Bean
+    protected AWSLambdaConfigurerAdapter lambdaAdapter() {
+        return new AWSLambdaConfigurerAdapter(
+                amazonProperties.getAws().getAccessKeyId(),
+                amazonProperties.getAws().getAccessKeySecret());
+    }
+}

spring-boot-starter-aws-lambda/src/main/java/amazon/aws/AmazonProperties.java

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+package amazon.aws;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.NestedConfigurationProperty;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Configuration property group for Amazon S3 and AWS
+ *
+ * @author kbastani
+ */
+@Configuration
+@ConfigurationProperties(prefix = "amazon")
+public class AmazonProperties {
+
+    @NestedConfigurationProperty
+    private Aws aws;
+
+    /**
+     * A property group for Amazon Web Service (AWS) configurations
+     *
+     * @return a property group for AWS configurations
+     */
+    public Aws getAws() {
+        return aws;
+    }
+
+    /**
+     * A property group for Amazon Web Service (AWS) configurations
+     *
+     * @param aws is a property group for AWS configurations
+     */
+    public void setAws(Aws aws) {
+        this.aws = aws;
+    }
+
+    /**
+     * A property group for Amazon Web Service (AWS) configurations
+     */
+    public static class Aws {
+
+        private String accessKeyId;
+        private String accessKeySecret;
+
+        /**
+         * A valid AWS account's access key id.
+         *
+         * @return an AWS access key id
+         */
+        public String getAccessKeyId() {
+            return accessKeyId;
+        }
+
+        /**
+         * A valid AWS account's access key id.
+         *
+         * @param accessKeyId is a valid AWS account's access key id.
+         */
+        public void setAccessKeyId(String accessKeyId) {
+            this.accessKeyId = accessKeyId;
+        }
+
+        /**
+         * A valid AWS account's secret access token.
+         *
+         * @return an AWS account's secret access key
+         */
+        public String getAccessKeySecret() {
+            return accessKeySecret;
+        }
+
+        /**
+         * A valid AWS account's secret access token.
+         *
+         * @param accessKeySecret is a valid AWS account's secret access token.
+         */
+        public void setAccessKeySecret(String accessKeySecret) {
+            this.accessKeySecret = accessKeySecret;
+        }
+
+        @Override
+        public String toString() {
+            return "Aws{" +
+                    "accessKeyId='" + accessKeyId + '\'' +
+                    ", accessKeySecret='" + accessKeySecret + '\'' +
+                    '}';
+        }
+    }
+}

spring-boot-starter-aws-lambda/src/main/resources/META-INF/spring-configuration-metadata.json

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+{
+  "groups": [
+    {
+      "name": "amazon",
+      "type": "amazon.aws.AmazonProperties",
+      "sourceType": "amazon.aws.AmazonProperties"
+    }
+  ]
+}

spring-boot-starter-aws-lambda/src/main/resources/META-INF/spring.factories

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+org.springframework.boot.autoconfigure.EnableAutoConfiguration=amazon.aws.AmazonAutoConfiguration

spring-boot-starter-aws-lambda/src/main/resources/application.properties

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+amazon.aws.access-key-id=replace
+amazon.aws.access-key-secret=replace

spring-boot-starter-aws-lambda/src/test/java/amazon/aws/AmazonConfigurationTest.java

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+package amazon.aws;
+
+import org.junit.After;
+import org.junit.Test;
+import org.springframework.boot.test.util.EnvironmentTestUtils;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
+
+import static junit.framework.TestCase.assertNotNull;
+
+public class AmazonConfigurationTest {
+
+    private AnnotationConfigApplicationContext context;
+
+    @After
+    public void tearDown() {
+        if (this.context != null) {
+            this.context.close();
+        }
+    }
+
+    @Test
+    public void defaultAdapter() {
+        load(EmptyConfiguration.class,
+                "amazon.aws.access-key-id=AJGLDLSXKDFLS",
+                "amazon.aws.access-key-secret=XSDFSDFLKKHASDFJALASDF");
+
+        AWSLambdaConfigurerAdapter amazonS3Template = this.context.getBean(AWSLambdaConfigurerAdapter.class);
+        assertNotNull(amazonS3Template);
+    }
+
+    @Configuration
+    static class EmptyConfiguration {
+    }
+
+    private void load(Class<?> config, String... environment) {
+        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext();
+        EnvironmentTestUtils.addEnvironment(applicationContext, environment);
+        applicationContext.register(config);
+        applicationContext.register(AmazonAutoConfiguration.class);
+        applicationContext.refresh();
+        this.context = applicationContext;
+    }
+}