chore: Update UA configurator to comply with 50 chars limit

powertools-common/src/main/java/software/amazon/lambda/powertools/common/internal/UserAgentConfigurator.java

@@ -82,25 +82,52 @@ static String getVersionFromProperties(String propertyFileName, String versionKe
 
     /**
      * Configures the AWS SDK to use Powertools user agent by setting the sdk.ua.appId system property.
-     * If the property is already set and not empty, appends the Powertools user agent with a "/" separator.
+     * Preserves any user-provided value and replaces any existing Powertools user agent.
+     * Enforces a 50 character limit to comply with AWS SDK recommendations.
      * This should be called during library initialization to ensure the user agent is properly configured.
      */
     public static void configureUserAgent(String ptFeature) {
         try {
             String existingValue = System.getProperty(SDK_USER_AGENT_APP_ID);
             String powertoolsUserAgent = getUserAgent(ptFeature);
+            String newValue;
 
-            if (existingValue != null && !existingValue.isEmpty()) {
-                System.setProperty(SDK_USER_AGENT_APP_ID, existingValue + "/" + powertoolsUserAgent);
+            if (existingValue == null || existingValue.isEmpty()) {
+                newValue = powertoolsUserAgent;
             } else {
-                System.setProperty(SDK_USER_AGENT_APP_ID, powertoolsUserAgent);
+                String userValue = extractUserValue(existingValue);
+                if (userValue.isEmpty()) {
+                    newValue = powertoolsUserAgent;
+                } else {
+                    newValue = userValue + "/" + powertoolsUserAgent;
+                }
+            }
+
+            if (newValue.length() <= 50) {
+                System.setProperty(SDK_USER_AGENT_APP_ID, newValue);
             }
         } catch (Exception e) {
             // We don't re-raise since we don't want to break the user if something in this logic doesn't work
             LOG.warn("Unable to configure user agent system property", e);
         }
     }
 
+    /**
+     * Extracts the user-provided value from the existing user agent string by removing any Powertools user agent.
+     * A Powertools user agent follows the pattern "PT/{FEATURE}/{VERSION} PTENV/{ENV}".
+     *
+     * @param existingValue the existing user agent string
+     * @return the user-provided value without Powertools user agent, or empty string if none exists
+     */
+    static String extractUserValue(String existingValue) {
+        if (existingValue == null || existingValue.isEmpty()) {
+            return "";
+        }
+        // Remove Powertools user agent pattern: PT/{FEATURE}/{VERSION} PTENV/{ENV}
+        String result = existingValue.replaceAll("/?PT/[^/]+/[^ ]+ PTENV/[^ ]+", "");
+        return result.trim();
+    }
+
     /**
      * Retrieves the user agent string for the Powertools for AWS Lambda.
      * It follows the pattern PT/{PT_FEATURE}/{PT_VERSION} PTENV/{PT_EXEC_ENV}

powertools-common/src/test/java/software/amazon/lambda/powertools/common/internal/UserAgentConfiguratorTest.java

@@ -131,14 +131,72 @@ void testConfigureUserAgent() {
     }
 
     @Test
-    void testConfigureUserAgent_WithExistingValue() {
+    void testConfigureUserAgent_WithExistingUserValue() {
         System.setProperty("sdk.ua.appId", "UserValueABC123");
         UserAgentConfigurator.configureUserAgent("test-feature");
 
         assertThat(System.getProperty("sdk.ua.appId"))
                 .isEqualTo("UserValueABC123/PT/TEST-FEATURE/" + VERSION + " PTENV/NA");
     }
 
+    @Test
+    void testConfigureUserAgent_ReplacePowertoolsUserAgent() {
+        System.setProperty("sdk.ua.appId", "PT/BATCH/" + VERSION + " PTENV/NA");
+        UserAgentConfigurator.configureUserAgent("logging-log4j");
+
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("PT/LOGGING-LOG4J/" + VERSION + " PTENV/NA");
+    }
+
+    @Test
+    void testConfigureUserAgent_PreserveUserValueAndReplacePowertools() {
+        System.setProperty("sdk.ua.appId", "UserValue/PT/BATCH/" + VERSION + " PTENV/NA");
+        UserAgentConfigurator.configureUserAgent("tracing");
+
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("UserValue/PT/TRACING/" + VERSION + " PTENV/NA");
+    }
+
+    @Test
+    void testConfigureUserAgent_ExceedsLimit() {
+        System.setProperty("sdk.ua.appId", "VeryLongUserValueThatExceedsTheLimitWhenCombined");
+        UserAgentConfigurator.configureUserAgent("test-feature");
+
+        // Should not update if it would exceed 50 characters
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("VeryLongUserValueThatExceedsTheLimitWhenCombined");
+    }
+
+    @Test
+    void testExtractUserValue_NoUserValue() {
+        String result = UserAgentConfigurator.extractUserValue("PT/BATCH/" + VERSION + " PTENV/NA");
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void testExtractUserValue_WithUserValue() {
+        String result = UserAgentConfigurator.extractUserValue("UserValue/PT/BATCH/" + VERSION + " PTENV/NA");
+        assertThat(result).isEqualTo("UserValue");
+    }
+
+    @Test
+    void testExtractUserValue_EmptyString() {
+        String result = UserAgentConfigurator.extractUserValue("");
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void testExtractUserValue_NullString() {
+        String result = UserAgentConfigurator.extractUserValue(null);
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    void testExtractUserValue_OnlyUserValue() {
+        String result = UserAgentConfigurator.extractUserValue("MyCustomValue");
+        assertThat(result).isEqualTo("MyCustomValue");
+    }
+
     @Test
     void testConfigureUserAgent_WithEmptyExistingValue() {
         System.setProperty("sdk.ua.appId", "");
@@ -148,4 +206,25 @@ void testConfigureUserAgent_WithEmptyExistingValue() {
                 .isEqualTo("PT/TEST-FEATURE/" + VERSION + " PTENV/NA");
     }
 
+    @Test
+    @SetEnvironmentVariable(key = AWS_EXECUTION_ENV, value = "AWS_Lambda_java11")
+    void testConfigureUserAgent_MultipleUtilities() {
+        System.clearProperty("sdk.ua.appId");
+
+        // First utility
+        UserAgentConfigurator.configureUserAgent("batch");
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("PT/BATCH/" + VERSION + " PTENV/AWS_Lambda_java11");
+
+        // Second utility - should replace, not append
+        UserAgentConfigurator.configureUserAgent("logging-log4j");
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("PT/LOGGING-LOG4J/" + VERSION + " PTENV/AWS_Lambda_java11");
+
+        // Third utility - should replace again
+        UserAgentConfigurator.configureUserAgent("tracing");
+        assertThat(System.getProperty("sdk.ua.appId"))
+                .isEqualTo("PT/TRACING/" + VERSION + " PTENV/AWS_Lambda_java11");
+    }
+
 }