Re-introduce a no-args constructor for LoggingConfigSourceInterceptor...

implementation/src/main/java/io/smallrye/config/LoggingConfigSourceInterceptor.java

@@ -12,6 +12,10 @@ public class LoggingConfigSourceInterceptor implements ConfigSourceInterceptor {
 
     private final boolean enabled;
 
+    public LoggingConfigSourceInterceptor() {
+        this(true);
+    }
+
     public LoggingConfigSourceInterceptor(final boolean enabled) {
         this.enabled = enabled;
     }

implementation/src/test/java/io/smallrye/config/LoggingConfigSourceInterceptorTest.java

@@ -73,6 +73,36 @@ void interceptor() throws Exception {
         assertTrue(logs.contains("SRCFG01001: The config secret was loaded from secret with the value secret"));
     }
 
+    @Test
+    void explicitInterceptor() throws Exception {
+        Config config = new SmallRyeConfigBuilder()
+                .addDefaultSources()
+                .addDefaultInterceptors()
+                .withInterceptors(new LoggingConfigSourceInterceptor())
+                .withSources(new ConfigValuePropertiesConfigSource(
+                        LoggingConfigSourceInterceptorTest.class.getResource("/config-values.properties")))
+                .withSecretKeys("secret")
+                .build();
+
+        assertEquals("abc", config.getValue("my.prop", String.class));
+        // No log is done here to not expose any sensitive information
+        assertThrows(SecurityException.class, () -> config.getValue("secret", String.class));
+        assertThrows(NoSuchElementException.class, () -> config.getValue("not.found", String.class));
+
+        // This should not log the secret value:
+        assertEquals("12345678", SecretKeys.doUnlocked(() -> config.getValue("secret", String.class)));
+
+        List<String> logs = logCapture.records().stream().map(LogRecord::getMessage).collect(toList());
+        // my.prop lookup
+        assertTrue(logs.stream()
+                .anyMatch(log -> log.contains("The config my.prop was loaded from ConfigValuePropertiesConfigSource")));
+        assertTrue(logs.stream().anyMatch(log -> log.contains(":1 with the value abc")));
+        // not.found lookup
+        assertTrue(logs.contains("SRCFG01002: The config not.found was not found"));
+        // secret lookup, shows the key but hides the source and value
+        assertTrue(logs.contains("SRCFG01001: The config secret was loaded from secret with the value secret"));
+    }
+
     @Test
     void expansion() {
         SmallRyeConfig config = new SmallRyeConfigBuilder()