Reports failure when reporting fails. (#36)

* Reports failure when reporting fails.

fixes #35

* Also let the LoggerReporter reports error upon failure.

Author: Takashi Matsuo

src/Trace/Reporter/GoogleCloudReporter.php

@@ -177,6 +177,7 @@ public function report(TracerInterface $tracer)
                 return self::$client->insert($trace);
             }
         } catch (\Exception $e) {
+            error_log('Reporting the Trace data failed: ' . $e->getMessage());
             return false;
         }
     }

src/Trace/Reporter/LoggerReporter.php

@@ -61,6 +61,7 @@ public function report(TracerInterface $tracer)
         try {
             $this->logger->log($this->level, json_encode($tracer->spans()));
         } catch (\Exception $e) {
+            error_log('Reporting the Trace data failed: ' . $e->getMessage());
             return false;
         }
         return true;

tests/unit/Trace/Reporter/GoogleCloudReporterTest.php

@@ -17,6 +17,8 @@
 
 namespace OpenCensus\Tests\Unit\Trace\Reporter;
 
+require_once __DIR__ . '/mock_error_log.php';
+
 use OpenCensus\Trace\Reporter\GoogleCloudReporter;
 use OpenCensus\Trace\TraceContext;
 use OpenCensus\Trace\Tracer\TracerInterface;
@@ -61,6 +63,25 @@ public function testFormatsTrace()
         }
     }
 
+    public function testReportWithAnExceptionErrorLog()
+    {
+        $tracer = new ContextTracer(new TraceContext('testtraceid'));
+        $tracer->inSpan(['name' => 'main'], function () {});
+        $this->client->insert(Argument::any())->willThrow(
+            new \Exception('error_log test')
+        );
+        $trace = $this->prophesize(Trace::class);
+        $trace->setSpans(Argument::any())->shouldBeCalled();
+        $this->client->trace(Argument::any())->willReturn($trace->reveal());
+        $reporter = new GoogleCloudReporter(
+            ['client' => $this->client->reveal()]
+        );
+        $this->expectOutputString(
+            'Reporting the Trace data failed: error_log test'
+        );
+        $this->assertFalse($reporter->report($tracer));
+    }
+
     public function testHandlesKind()
     {
         $tracer = new ContextTracer(new TraceContext('testtraceid'));

tests/unit/Trace/Reporter/LoggerReporterTest.php

@@ -17,6 +17,8 @@
 
 namespace OpenCensus\Tests\Unit\Trace\Reporter;
 
+require_once __DIR__ . '/mock_error_log.php';
+
 use Psr\Log\LoggerInterface;
 use OpenCensus\Trace\Reporter\LoggerReporter;
 use OpenCensus\Trace\TraceContext;
@@ -38,6 +40,28 @@ public function setUp()
         $this->tracer = $this->prophesize(TracerInterface::class);
     }
 
+    public function testReportWithAnExceptionErrorLog()
+    {
+        $spans = [
+            new TraceSpan([
+                'name' => 'span',
+                'startTime' => microtime(true),
+                'endTime' => microtime(true) + 10
+            ])
+        ];
+        $this->tracer->context()->willReturn(new TraceContext('testtraceid'));
+        $this->tracer->spans()->willReturn($spans);
+        $this->logger->log('some-level', Argument::type('string'))->willThrow(
+            new \Exception('error_log test')
+        );
+
+        $reporter = new LoggerReporter($this->logger->reveal(), 'some-level');
+        $this->expectOutputString(
+            'Reporting the Trace data failed: error_log test'
+        );
+        $this->assertFalse($reporter->report($this->tracer->reveal()));
+    }
+
     public function testLogsTrace()
     {
         $spans = [

tests/unit/Trace/Reporter/mock_error_log.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Copyright 2017 OpenCensus Authors
+ *
+ * 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.
+ */
+
+namespace OpenCensus\Trace\Reporter;
+
+/**
+ * A mock function for testing error_log function.
+ */
+
+function error_log($msg)
+{
+    echo $msg;
+}