Create a log wrapper and better test GDLLogWriter (#2190)

* Add logTarget as a property to GDLLogEvent and connect the logger to the writer.

* Create a log wrapper for use with GULLogger.

* GDLLogTransformer should inherit <NSObject> and require transform:

* Protect against doesNotRespond exceptions and expand tests

* Style and a missing @param.

* Update a comment

Author: mikehaney24

GoogleDataLogger.podspec

@@ -27,6 +27,8 @@ Shared library for iOS SDK data logging needs.
   s.source_files = 'GoogleDataLogger/GoogleDataLogger/**/*'
   s.public_header_files = 'GoogleDataLogger/GoogleDataLogger/Classes/Public/*.h'
 
+  s.dependency 'GoogleUtilities/Logger'
+
   s.pod_target_xcconfig = {
     'GCC_C_LANGUAGE_STANDARD' => 'c99'
   }

GoogleDataLogger/GoogleDataLogger/Classes/GDLLogEvent.h

@@ -44,6 +44,9 @@ typedef NS_ENUM(NSInteger, GDLLogQoS) {
 /** The log map identifier, to allow backends to map the extension property to a proto. */
 @property(readonly, nonatomic) NSString *logMapID;
 
+/** The identifier for the backend this log will eventually be sent to. */
+@property(readonly, nonatomic) NSInteger logTarget;
+
 /** The log object itself, encapsulated in the transport of your choice, as long as it implements
  * the GDLLogProto protocol. */
 @property(nonatomic) id<GDLLogProto> extension;
@@ -60,9 +63,11 @@ typedef NS_ENUM(NSInteger, GDLLogQoS) {
 /** Initializes an instance using the given logMapID.
  *
  * @param logMapID The log map identifier.
+ * @param logTarget The log's target identifier.
  * @return An instance of this class.
  */
-- (instancetype)initWithLogMapID:(NSString *)logMapID NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithLogMapID:(NSString *)logMapID
+                       logTarget:(NSInteger)logTarget NS_DESIGNATED_INITIALIZER;
 
 @end
 

GoogleDataLogger/GoogleDataLogger/Classes/GDLLogEvent.m

@@ -18,11 +18,13 @@
 
 @implementation GDLLogEvent
 
-- (instancetype)initWithLogMapID:(NSString *)logMapID {
+- (instancetype)initWithLogMapID:(NSString *)logMapID logTarget:(NSInteger)logTarget {
   NSAssert(logMapID.length > 0, @"Please give a valid log map ID");
+  NSAssert(logTarget > 0, @"A log target cannot be negative or 0");
   self = [super init];
   if (self) {
     _logMapID = logMapID;
+    _logTarget = logTarget;
   }
   return self;
 }

GoogleDataLogger/GoogleDataLogger/Classes/GDLLogWriter.m

@@ -19,6 +19,7 @@
 
 #import <GoogleDataLogger/GDLLogTransformer.h>
 
+#import "GDLConsoleLogger.h"
 #import "GDLLogStorage.h"
 
 @implementation GDLLogWriter
@@ -48,8 +49,14 @@ - (void)writeLog:(GDLLogEvent *)log
   dispatch_async(_logWritingQueue, ^{
     GDLLogEvent *transformedLog = log;
     for (id<GDLLogTransformer> transformer in logTransformers) {
-      transformedLog = [transformer transform:transformedLog];
-      if (!transformedLog) {
+      if ([transformer respondsToSelector:@selector(transform:)]) {
+        transformedLog = [transformer transform:transformedLog];
+        if (!transformedLog) {
+          return;
+        }
+      } else {
+        GDLLogWarning(GDLMCWTransformerDoesntImplementTransform,
+                      @"Transformer doesn't implement transform: %@", transformer);
         return;
       }
     }

GoogleDataLogger/GoogleDataLogger/Classes/GDLLogger.m

@@ -17,6 +17,7 @@
 #import "GDLLogger.h"
 
 #import "GDLLogEvent.h"
+#import "GDLLogWriter.h"
 
 @interface GDLLogger ()
 
@@ -49,18 +50,16 @@ - (instancetype)initWithLogMapID:(NSString *)logMapID
 
 - (void)logTelemetryEvent:(GDLLogEvent *)logEvent {
   NSAssert(logEvent, @"You can't log a nil event");
-
-  // TODO(mikehaney24): Implement.
+  [[GDLLogWriter sharedInstance] writeLog:logEvent afterApplyingTransformers:_logTransformers];
 }
 
 - (void)logDataEvent:(GDLLogEvent *)logEvent {
   NSAssert(logEvent, @"You can't log a nil event");
-
-  // TODO(mikehaney24): Implement.
+  [[GDLLogWriter sharedInstance] writeLog:logEvent afterApplyingTransformers:_logTransformers];
 }
 
 - (GDLLogEvent *)newEvent {
-  return [[GDLLogEvent alloc] initWithLogMapID:_logMapID];
+  return [[GDLLogEvent alloc] initWithLogMapID:_logMapID logTarget:_logTarget];
 }
 
 @end

GoogleDataLogger/GoogleDataLogger/Classes/Public/GDLLogTransformer.h

@@ -19,7 +19,9 @@
 @class GDLLogEvent;
 
 /** Defines the API that log transformers must adopt. */
-@protocol GDLLogTransformer
+@protocol GDLLogTransformer <NSObject>
+
+@required
 
 /** Transforms a log by applying some logic to it. Logs returned can be nil, for example, in
  *  instances where the log should be sampled.

GoogleDataLogger/GoogleDataLogger/DependencyWrappers/GDLConsoleLogger.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GULLogger.h"
+
+/** The console logger prefix. */
+static GULLoggerService kGDLConsoleLogger = @"[GoogleDataLogger]";
+
+/** A list of message codes to print in the logger that help to correspond printed messages with
+ * code locations.
+ *
+ * Prefixes:
+ * - MCW => MessageCodeWarning
+ */
+typedef NS_ENUM(NSInteger, GDLMessageCode) {
+
+  /** For warning messages concerning transform: not being implemented by a log transformer. */
+  GDLMCWTransformerDoesntImplementTransform = 1
+};
+
+/** */
+FOUNDATION_EXTERN NSString *GDLMessageCodeEnumToString(GDLMessageCode code);
+
+/** Logs the warningMessage string to the console at the warning level.
+ *
+ * @param warningMessageFormat The format string to log to the console.
+ */
+FOUNDATION_EXTERN void GDLLogWarning(GDLMessageCode messageCode,
+                                     NSString *warningMessageFormat,
+                                     ...) NS_FORMAT_FUNCTION(2, 3);
+
+// A define to wrap GULLogWarning with slightly more convenient usage.
+#define GDLLogWarning(MESSAGE_CODE, MESSAGE_FORMAT, ...)                                          \
+  GULLogWarning(kGDLConsoleLogger, YES, GDLMessageCodeEnumToString(MESSAGE_CODE), MESSAGE_FORMAT, \
+                __VA_ARGS__);

GoogleDataLogger/GoogleDataLogger/DependencyWrappers/GDLConsoleLogger.m

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "GDLConsoleLogger.h"
+
+NSString* GDLMessageCodeEnumToString(GDLMessageCode code) {
+  return [[NSString alloc] initWithFormat:@"I-GDL%06ld", (long)code];
+}

GoogleDataLogger/Tests/GDLLogEventTest.m

@@ -25,8 +25,8 @@ @interface GDLLogEventTest : XCTestCase
 @implementation GDLLogEventTest
 
 - (void)testInit {
-  XCTAssertNotNil([[GDLLogEvent alloc] initWithLogMapID:@"1"]);
-  XCTAssertThrows([[GDLLogEvent alloc] initWithLogMapID:@""]);
+  XCTAssertNotNil([[GDLLogEvent alloc] initWithLogMapID:@"1" logTarget:1]);
+  XCTAssertThrows([[GDLLogEvent alloc] initWithLogMapID:@"" logTarget:1]);
 }
 
 @end

GoogleDataLogger/Tests/GDLLogWriterTest.m

@@ -34,6 +34,18 @@ - (GDLLogEvent *)transform:(GDLLogEvent *)logEvent {
 
 @end
 
+@interface GDLLogWriterTestNewLogTransformer : NSObject <GDLLogTransformer>
+
+@end
+
+@implementation GDLLogWriterTestNewLogTransformer
+
+- (GDLLogEvent *)transform:(GDLLogEvent *)logEvent {
+  return [[GDLLogEvent alloc] initWithLogMapID:@"new" logTarget:1];
+}
+
+@end
+
 @interface GDLLogWriterTest : XCTestCase
 
 @end
@@ -50,18 +62,20 @@ - (void)testSharedInstance {
   XCTAssertEqual([GDLLogWriter sharedInstance], [GDLLogWriter sharedInstance]);
 }
 
+/** Tests writing a log without a transformer. */
 - (void)testWriteLogWithoutTransformers {
   GDLLogWriter *writer = [GDLLogWriter sharedInstance];
-  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"1"];
+  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"1" logTarget:1];
   XCTAssertNoThrow([writer writeLog:log afterApplyingTransformers:nil]);
   dispatch_sync(writer.logWritingQueue, ^{
                     // TODO(mikehaney24): Assert that storage contains the log.
                 });
 }
 
+/** Tests writing a log with a transformer that nils out the log. */
 - (void)testWriteLogWithTransformersThatNilTheLog {
   GDLLogWriter *writer = [GDLLogWriter sharedInstance];
-  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"2"];
+  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"2" logTarget:1];
   NSArray<id<GDLLogTransformer>> *transformers =
       @[ [[GDLLogWriterTestNilingTransformer alloc] init] ];
   XCTAssertNoThrow([writer writeLog:log afterApplyingTransformers:transformers]);
@@ -70,4 +84,31 @@ - (void)testWriteLogWithTransformersThatNilTheLog {
                 });
 }
 
+/** Tests writing a log with a transformer that creates a new log. */
+- (void)testWriteLogWithTransformersThatCreateANewLog {
+  GDLLogWriter *writer = [GDLLogWriter sharedInstance];
+  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"2" logTarget:1];
+  NSArray<id<GDLLogTransformer>> *transformers =
+      @[ [[GDLLogWriterTestNewLogTransformer alloc] init] ];
+  XCTAssertNoThrow([writer writeLog:log afterApplyingTransformers:transformers]);
+  dispatch_sync(writer.logWritingQueue, ^{
+                    // TODO(mikehaney24): Assert that storage contains the new log.
+                });
+}
+
+/** Tests that using a transformer without transform: implemented throws. */
+- (void)testWriteLogWithBadTransformer {
+  GDLLogWriter *writer = [GDLLogWriter sharedInstance];
+  GDLLogEvent *log = [[GDLLogEvent alloc] initWithLogMapID:@"2" logTarget:1];
+  NSArray *transformers = @[ [[NSObject alloc] init] ];
+  @try {
+    dispatch_sync(writer.logWritingQueue, ^{
+      // TODO(mikehaney24): Assert that storage contains the new log.
+      [writer writeLog:log afterApplyingTransformers:transformers];
+    });
+  } @catch (NSException *exception) {
+    NSLog(@"");
+  }
+}
+
 @end