Exclude log by Event Id (#53)

* Added excludeLogEventIds options to client. The logger will exclude logs if the log event id is on the provided list.
Prepare 9.3.0 release.

* Replace eventId exclude list with filter function callback option.

* Rework based on code review.

* Remove unused imports.

* Fix method order. Add missing JavaDoc.

* Update src/main/java/com/configcat/ConfigCatClient.java

Co-authored-by: adams85 <31276480+adams85@users.noreply.github.com>

* Fix interface visibility.

---------

Co-authored-by: adams85 <31276480+adams85@users.noreply.github.com>

Author: novalisdenahi

gradle.properties

@@ -1 +1 @@
-version=9.2.0
+version=9.3.0

src/main/java/com/configcat/ConfigCatClient.java

@@ -28,7 +28,7 @@ public final class ConfigCatClient implements ConfigurationProvider {
     private final LogLevel clientLogLevel;
 
     private ConfigCatClient(String sdkKey, Options options) {
-        this.logger = new ConfigCatLogger(LoggerFactory.getLogger(ConfigCatClient.class), options.logLevel, options.configCatHooks);
+        this.logger = new ConfigCatLogger(LoggerFactory.getLogger(ConfigCatClient.class), options.logLevel, options.configCatHooks, options.logFilter);
         this.clientLogLevel = options.logLevel;
 
         this.sdkKey = sdkKey;
@@ -707,6 +707,7 @@ public static class Options {
         private User defaultUser;
         private boolean offline = false;
         private final ConfigCatHooks configCatHooks = new ConfigCatHooks();
+        private LogFilterFunction logFilter;
 
 
         /**
@@ -813,6 +814,13 @@ public ConfigCatHooks hooks() {
             return configCatHooks;
         }
 
+        /**
+         * Set the client's log filter callback function. When logFilterFunction returns false, the ConfigCatLogger skips the log event.
+         */
+        public void logFilter(LogFilterFunction logFilter) {
+            this.logFilter = logFilter;
+        }
+
         private boolean isBaseURLCustom() {
             return this.baseUrl != null && !this.baseUrl.isEmpty();
         }

src/main/java/com/configcat/ConfigCatLogger.java

@@ -6,50 +6,56 @@ class ConfigCatLogger {
     private final Logger logger;
     private final LogLevel logLevel;
     private final ConfigCatHooks configCatHooks;
+    private final LogFilterFunction filterFunction ;
 
-    public ConfigCatLogger(Logger logger, LogLevel logLevel, ConfigCatHooks configCatHooks) {
+    public ConfigCatLogger(Logger logger, LogLevel logLevel, ConfigCatHooks configCatHooks, LogFilterFunction filterFunction ) {
         this.logger = logger;
         this.logLevel = logLevel;
         this.configCatHooks = configCatHooks;
+        this.filterFunction  = filterFunction ;
     }
 
     public ConfigCatLogger(Logger logger, LogLevel logLevel) {
-        this(logger, logLevel, null);
+        this(logger, logLevel, null, null);
     }
 
     public ConfigCatLogger(Logger logger) {
         this(logger, LogLevel.WARNING);
     }
 
     public void warn(int eventId, String message) {
-        if (this.logLevel.ordinal() <= LogLevel.WARNING.ordinal()) {
+        if (filter(eventId,  LogLevel.WARNING, message, null)) {
             this.logger.warn("[{}] {}", eventId, message);
         }
     }
 
     public void error(int eventId, String message, Exception exception) {
         if (this.configCatHooks != null) this.configCatHooks.invokeOnError(message);
-        if (this.logLevel.ordinal() <= LogLevel.ERROR.ordinal()) {
+        if (filter(eventId,  LogLevel.ERROR, message, exception)) {
             this.logger.error("[{}] {}", eventId, message, exception);
         }
     }
 
     public void error(int eventId, String message) {
         if (this.configCatHooks != null) this.configCatHooks.invokeOnError(message);
-        if (this.logLevel.ordinal() <= LogLevel.ERROR.ordinal()) {
+        if (filter(eventId,  LogLevel.ERROR, message, null)) {
             this.logger.error("[{}] {}", eventId, message);
         }
     }
 
     public void info(int eventId, String message) {
-        if (this.logLevel.ordinal() <= LogLevel.INFO.ordinal()) {
+        if (filter(eventId,  LogLevel.INFO, message, null)) {
             this.logger.info("[{}] {}", eventId, message);
         }
     }
 
     public void debug(String message) {
-        if (this.logLevel.ordinal() <= LogLevel.DEBUG.ordinal()) {
+        if (filter(0,  LogLevel.DEBUG, message, null)) {
             this.logger.debug("[{}] {}", 0, message);
         }
     }
+
+    private boolean filter(int eventId, LogLevel logLevel, String message, Exception exception) {
+        return this.logLevel.ordinal() <= logLevel.ordinal() && (this.filterFunction == null || this.filterFunction.apply(logLevel, eventId, message, exception));
+    }
 }

src/main/java/com/configcat/Constants.java

@@ -7,7 +7,7 @@ private Constants() { /* prevent from instantiation*/ }
     static final long DISTANT_PAST = 0;
     static final String CONFIG_JSON_NAME = "config_v6.json";
     static final String SERIALIZATION_FORMAT_VERSION = "v2";
-    static final String VERSION = "9.2.0";
+    static final String VERSION = "9.3.0";
 
     static final String SDK_KEY_PROXY_PREFIX = "configcat-proxy/";
     static final String SDK_KEY_PREFIX = "configcat-sdk-1";

src/main/java/com/configcat/LogFilterFunction.java

@@ -0,0 +1,19 @@
+package com.configcat;
+
+/**
+ * The Log Filter Functional Interface provides a custom filter option for the ConfigCat Logger.
+ */
+@FunctionalInterface
+public interface LogFilterFunction {
+
+    /**
+     * Apply the custom filter option to the ConfigCatLogger.
+     *
+     * @param logLevel  Event severity level.
+     * @param eventId  Event identifier.
+     * @param message Message.
+     * @param exception The exception object related to the message (if any).
+     * @return True to log the event, false will leave out the log.
+     */
+     boolean apply(LogLevel logLevel, int eventId, String message, Throwable exception);
+}

src/test/java/com/configcat/LoggerTests.java

@@ -87,4 +87,29 @@ public void noLog() {
         verify(mockLogger, never()).warn(anyString(), eq(3000), eq("warn"));
         verify(mockLogger, never()).error(anyString(), eq(1000), eq("error"), any(Exception.class));
     }
+
+    @Test
+    public void excludeLogEvents() {
+        Logger mockLogger = mock(Logger.class);
+
+        LogFilterFunction filterLogFunction = ( LogLevel logLevel, int eventId, String message, Throwable exception) -> eventId != 1001 && eventId != 3001 && eventId != 5001;
+
+        ConfigCatLogger logger = new ConfigCatLogger(mockLogger, LogLevel.INFO, null, filterLogFunction);
+
+        logger.debug("[0] debug");
+        logger.info(5000, "info");
+        logger.warn(3000, "warn");
+        logger.error(1000, "error", new Exception());
+        logger.info(5001, "info");
+        logger.warn(3001, "warn");
+        logger.error(1001, "error", new Exception());
+
+        verify(mockLogger, never()).debug(anyString(), eq(0), eq("debug"));
+        verify(mockLogger, times(1)).info(anyString(), eq(5000), eq("info"));
+        verify(mockLogger, times(1)).warn(anyString(), eq(3000), eq("warn"));
+        verify(mockLogger, times(1)).error(anyString(), eq(1000), eq("error"), any(Exception.class));
+        verify(mockLogger, never()).info(anyString(), eq(5001), eq("info"));
+        verify(mockLogger, never()).warn(anyString(), eq(3001), eq("warn"));
+        verify(mockLogger, never()).error(anyString(), eq(1001), eq("error"), any(Exception.class));
+    }
 }