Add option to set property prefix on Parameter Store property sources

docs/src/main/asciidoc/parameter-store.adoc

@@ -61,6 +61,33 @@ spring.config.import[1]=aws-parameterstore=/config/optional-params/
 If you add indexed parameter names such as `/config/application/cloud.aws.stack_0_.name`, `/config/application/cloud.aws.stack_1_.name`, ... to Parameter Store,
 these will become accessible as array properties `cloud.aws.stack[0].name`, `cloud.aws.stack[1].name`, ... in Spring.
 
+==== Adding prefix to property keys
+
+To avoid property key collisions it is possible to configure a property key prefix that gets added to each resolved parameter.
+
+As an example, assuming the following parameters are stored under path `/config/my-datasource`:
+
+|===
+| Parameter Name | Parameter Value
+
+| `/config/my-datasource/url` | `jdbc:mysql://localhost:3306`
+
+| `/config/my-datasource/username` | `db-user`
+
+|===
+
+By default, `url` and `username` properties will be added to the Spring environment. To add a prefix to property keys configure `spring.config.import` property with `?prefix=` added to the parameter path:
+
+[source,properties]
+----
+spring.config.import=aws-parameterstore:/config/my-datasource/?prefix=spring.datasource.
+----
+
+With such config, properties `spring.datasource.url` and `spring.datasource.username` are added to the Spring environment.
+
+NOTE: Prefixes are added as-is to all property names returned by Parameter Store. If you want key names to be separated with a dot between the prefix and key name, make sure to add a trailing dot to the prefix.
+
+
 === Using SsmClient
 
 The starter automatically configures and registers a `SsmClient` bean in the Spring application context. The `SsmClient` bean can be used to create or retrieve parameters from Parameter Store.

spring-cloud-aws-autoconfigure/src/test/java/io/awspring/cloud/autoconfigure/config/parameterstore/ParameterStoreConfigDataLoaderIntegrationTests.java

@@ -76,6 +76,7 @@ class ParameterStoreConfigDataLoaderIntegrationTests {
 	static void beforeAll() {
 		putParameter(localstack, "/config/spring/message", "value from tests", REGION);
 		putParameter(localstack, "/config/spring/another-parameter", "another parameter value", REGION);
+		putParameter(localstack, "/config/second/secondMessage", "second value from tests", REGION);
 	}
 
 	@Test
@@ -91,6 +92,22 @@ void resolvesPropertyFromParameterStore() {
 		}
 	}
 
+	@Test
+	void resolvesPropertiesWithPrefixes() {
+		SpringApplication application = new SpringApplication(App.class);
+		application.setWebApplicationType(WebApplicationType.NONE);
+
+		try (ConfigurableApplicationContext context = runApplication(application,
+				"aws-parameterstore:/config/spring/?prefix=first.;/config/second/?prefix=second.")) {
+			assertThat(context.getEnvironment().getProperty("first.message")).isEqualTo("value from tests");
+			assertThat(context.getEnvironment().getProperty("first.another-parameter"))
+					.isEqualTo("another parameter value");
+			assertThat(context.getEnvironment().getProperty("second.secondMessage"))
+					.isEqualTo("second value from tests");
+			assertThat(context.getEnvironment().getProperty("non-existing-parameter")).isNull();
+		}
+	}
+
 	@Test
 	void clientIsConfiguredWithConfigurerProvidedToBootstrapRegistry() {
 		SpringApplication application = new SpringApplication(App.class);

spring-cloud-aws-parameter-store/src/main/java/io/awspring/cloud/parameterstore/ParameterStorePropertySource.java

@@ -40,20 +40,31 @@ public class ParameterStorePropertySource extends AwsPropertySource<ParameterSto
 	// logger must stay static non-final so that it can be set with a value in
 	// ParameterStoreConfigDataLoader
 	private static Log LOG = LogFactory.getLog(ParameterStorePropertySource.class);
-
+	private static final String PREFIX_PART = "?prefix=";
 	private final String context;
 
+	private final String parameterPath;
+
+	/**
+	 * Prefix that gets added to resolved property keys. Useful when same property keys are returned by multiple
+	 * parameter paths. sources.
+	 */
+	@Nullable
+	private final String prefix;
+
 	private final Map<String, Object> properties = new LinkedHashMap<>();
 
 	public ParameterStorePropertySource(String context, SsmClient ssmClient) {
 		super("aws-parameterstore:" + context, ssmClient);
 		this.context = context;
+		this.parameterPath = resolveParameterPath(context);
+		this.prefix = resolvePrefix(context);
 	}
 
 	@Override
 	public void init() {
-		GetParametersByPathRequest paramsRequest = GetParametersByPathRequest.builder().path(context).recursive(true)
-				.withDecryption(true).build();
+		GetParametersByPathRequest paramsRequest = GetParametersByPathRequest.builder().path(parameterPath)
+				.recursive(true).withDecryption(true).build();
 		getParameters(paramsRequest);
 	}
 
@@ -76,13 +87,45 @@ public Object getProperty(String name) {
 	private void getParameters(GetParametersByPathRequest paramsRequest) {
 		GetParametersByPathResponse paramsResult = this.source.getParametersByPath(paramsRequest);
 		for (Parameter parameter : paramsResult.parameters()) {
-			String key = parameter.name().replace(this.context, "").replace('/', '.').replaceAll("_(\\d)_", "[$1]");
+			String key = parameter.name().replace(this.parameterPath, "").replace('/', '.')
+					.replaceAll("_(\\d)_", "[$1]");
 			LOG.debug("Populating property retrieved from AWS Parameter Store: " + key);
-			this.properties.put(key, parameter.value());
+			String propertyKey = prefix != null ? prefix + key : key;
+			this.properties.put(propertyKey, parameter.value());
 		}
 		if (paramsResult.nextToken() != null) {
 			getParameters(paramsRequest.toBuilder().nextToken(paramsResult.nextToken()).build());
 		}
 	}
 
+	@Nullable
+	String getPrefix() {
+		return prefix;
+	}
+
+	String getContext() {
+		return context;
+	}
+
+	String getParameterPath() {
+		return parameterPath;
+	}
+
+	@Nullable
+	private static String resolvePrefix(String context) {
+		int prefixIndex = context.indexOf(PREFIX_PART);
+		if (prefixIndex != -1) {
+			return context.substring(prefixIndex + PREFIX_PART.length());
+		}
+		return null;
+	}
+
+	private static String resolveParameterPath(String context) {
+		int prefixIndex = context.indexOf(PREFIX_PART);
+		if (prefixIndex != -1) {
+			return context.substring(0, prefixIndex);
+		}
+		return context;
+	}
+
 }

spring-cloud-aws-parameter-store/src/test/java/io/awspring/cloud/parameterstore/ParameterStorePropertySourceTest.java

@@ -90,4 +90,41 @@ void arrayParameterNames() {
 			it.assertThat(propertySource.getProperty("key[1].nested[1].nestedValue")).isEqualTo("key_nestedValue2");
 		});
 	}
+
+	@Test
+	void resolvesPrefixAndParameterPathFromContext() {
+		ParameterStorePropertySource propertySource = new ParameterStorePropertySource("/config/myservice/?prefix=xxx",
+				ssmClient);
+		assertThat(propertySource.getName()).isEqualTo("aws-parameterstore:/config/myservice/?prefix=xxx");
+		assertThat(propertySource.getPrefix()).isEqualTo("xxx");
+		assertThat(propertySource.getContext()).isEqualTo("/config/myservice/?prefix=xxx");
+		assertThat(propertySource.getParameterPath()).isEqualTo("/config/myservice/");
+	}
+
+	@Test
+	void addsPrefixToParameter() {
+		ParameterStorePropertySource propertySource = new ParameterStorePropertySource("/config/myservice/?prefix=yyy.",
+				ssmClient);
+
+		Parameter parameter = Parameter.builder().name("key1").value("my parameter").build();
+		GetParametersByPathResponse parametersByPathResponse = GetParametersByPathResponse.builder()
+				.parameters(parameter).build();
+
+		when(ssmClient.getParametersByPath(any(GetParametersByPathRequest.class))).thenReturn(parametersByPathResponse);
+
+		propertySource.init();
+
+		assertThat(propertySource.getPropertyNames()).containsExactly("yyy.key1");
+		assertThat(propertySource.getProperty("yyy.key1")).isEqualTo("my parameter");
+		assertThat(propertySource.getProperty("key1")).isNull();
+	}
+
+	@Test
+	void copyPreservesPrefix() {
+		ParameterStorePropertySource propertySource = new ParameterStorePropertySource("/config/myservice/?prefix=yyy",
+				ssmClient);
+		ParameterStorePropertySource copy = propertySource.copy();
+		assertThat(propertySource.getContext()).isEqualTo(copy.getContext());
+		assertThat(propertySource.getPrefix()).isEqualTo(copy.getPrefix());
+	}
 }