got rid of Console.WriteLine (#89)

* got rid of Console.WriteLine

* addressed PR feedback - mostly rename StackDriver to stackdriver

Author: SergeyKanzhelev

src/OpenCensus.Exporter.ApplicationInsights/Implementation/MetricsExporterThread.cs

@@ -190,9 +190,6 @@ internal void Export()
                         });
                     this.telemetryClient.TrackMetric(metricTelemetry);
                 }
-
-                Console.WriteLine(view);
-                Console.WriteLine(data);
             }
         }
     }

src/OpenCensus.Exporter.Ocagent/Implementation/ExporterOcagentEventSource.cs

@@ -0,0 +1,63 @@
+// <copyright file="ExporterOcagentEventSource.cs" company="OpenCensus Authors">
+// Copyright 2018, 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.
+// </copyright>
+
+namespace OpenCensus.Exporter.Ocagent.Implementation
+{
+    using System;
+    using System.Diagnostics.Tracing;
+    using System.Globalization;
+    using System.Threading;
+
+    [EventSource(Name = "OpenCensus-Exporter-Ocagent")]
+    internal class ExporterOcagentEventSource : EventSource
+    {
+        public static readonly ExporterOcagentEventSource Log = new ExporterOcagentEventSource();
+
+        [NonEvent]
+        public void FailedToConvertToProtoDefinitionError(Exception ex)
+        {
+            if (Log.IsEnabled(EventLevel.Error, EventKeywords.All))
+            {
+                this.FailedToConvertToProtoDefinitionError(ToInvariantString(ex));
+            }
+        }
+
+        [Event(1, Message = "Exporter failed to convert SpanData content into GRPC proto definition. Data will not be sent. Exception: {0}", Level = EventLevel.Error)]
+        public void FailedToConvertToProtoDefinitionError(string ex)
+        {
+            this.WriteEvent(1, ex);
+        }
+
+        /// <summary>
+        /// Returns a culture-independent string representation of the given <paramref name="exception"/> object,
+        /// appropriate for diagnostics tracing.
+        /// </summary>
+        private static string ToInvariantString(Exception exception)
+        {
+            CultureInfo originalUICulture = Thread.CurrentThread.CurrentUICulture;
+
+            try
+            {
+                Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
+                return exception.ToString();
+            }
+            finally
+            {
+                Thread.CurrentThread.CurrentUICulture = originalUICulture;
+            }
+        }
+    }
+}

src/OpenCensus.Exporter.Ocagent/Implementation/SpanDataExtentions.cs

@@ -73,9 +73,11 @@ internal static Span ToProtoSpan(this ISpanData spanData)
             }
             catch (Exception e)
             {
-                Console.WriteLine(e);
-
-                // TODO: log
+                // TODO: Is there a way to handle this better?
+                // This type of error processing is very aggressive and doesn't follow the
+                // error handling practices when smart defaults should be used when possible.
+                // See: https://github.com/census-instrumentation/opencensus-csharp/blob/develop/docs/error-handling.md
+                ExporterOcagentEventSource.Log.FailedToConvertToProtoDefinitionError(e);
             }
 
             return null;

src/OpenCensus.Exporter.Stackdriver/Implementation/ExporterStackdriverEventSource.cs

@@ -0,0 +1,78 @@
+// <copyright file="ExporterStackdriverEventSource.cs" company="OpenCensus Authors">
+// Copyright 2018, 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.
+// </copyright>
+
+namespace OpenCensus.Exporter.Stackdriver.Implementation
+{
+    using System;
+    using System.Diagnostics.Tracing;
+    using System.Globalization;
+    using System.Threading;
+
+    [EventSource(Name = "OpenCensus-Exporter-Stackdriver")]
+    internal class ExporterStackdriverEventSource : EventSource
+    {
+        public static readonly ExporterStackdriverEventSource Log = new ExporterStackdriverEventSource();
+
+        [NonEvent]
+        public void UnknownProblemInWorkerThreadError(Exception ex)
+        {
+            if (Log.IsEnabled(EventLevel.Error, EventKeywords.All))
+            {
+                this.UnknownProblemInWorkerThreadError(ToInvariantString(ex));
+            }
+        }
+
+        [Event(1, Message = "Stackdriver exporter encountered an unknown error and will shut down. Exception: {0}", Level = EventLevel.Error)]
+        public void UnknownProblemInWorkerThreadError(string ex)
+        {
+            this.WriteEvent(1, ex);
+        }
+
+        [NonEvent]
+        public void UnknownProblemWhileCreatingStackdriverTimeSeriesError(Exception ex)
+        {
+            if (Log.IsEnabled(EventLevel.Error, EventKeywords.All))
+            {
+                this.UnknownProblemWhileCreatingStackdriverTimeSeriesError(ToInvariantString(ex));
+            }
+        }
+
+        [Event(2, Message = "Stackdriver exporter failed to create time series. Time series will be lost. Exception: {0}", Level = EventLevel.Error)]
+        public void UnknownProblemWhileCreatingStackdriverTimeSeriesError(string ex)
+        {
+            this.WriteEvent(2, ex);
+        }
+
+        /// <summary>
+        /// Returns a culture-independent string representation of the given <paramref name="exception"/> object,
+        /// appropriate for diagnostics tracing.
+        /// </summary>
+        private static string ToInvariantString(Exception exception)
+        {
+            CultureInfo originalUICulture = Thread.CurrentThread.CurrentUICulture;
+
+            try
+            {
+                Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
+                return exception.ToString();
+            }
+            finally
+            {
+                Thread.CurrentThread.CurrentUICulture = originalUICulture;
+            }
+        }
+    }
+}

src/OpenCensus.Exporter.Stackdriver/Implementation/MetricsConversions.cs

@@ -176,7 +176,7 @@ public static TypedValue CreateTypedValue(
         private static IList<long> CreateBucketCounts(IList<long> bucketCounts)
         {
             // The first bucket (underflow bucket) should always be 0 count because the Metrics first bucket
-            // is [0, first_bound) but StackDriver distribution consists of an underflow bucket (number 0).
+            // is [0, first_bound) but Stackdriver distribution consists of an underflow bucket (number 0).
             var ret = new List<long>();
             ret.Add(0L);
             ret.AddRange(bucketCounts);

src/OpenCensus.Exporter.Stackdriver/Implementation/StackdriverStatsExporter.cs

@@ -170,7 +170,7 @@ private void DoWork()
             }
             catch (Exception ex)
             {
-                Console.WriteLine(ex);
+                ExporterStackdriverEventSource.Log.UnknownProblemInWorkerThreadError(ex);
             }
         }
 
@@ -267,8 +267,7 @@ private void Export()
                 }
                 catch (RpcException e)
                 {
-                    // TODO - zeltser - figure out where to send the error from exception
-                    Console.WriteLine(e);
+                    ExporterStackdriverEventSource.Log.UnknownProblemWhileCreatingStackdriverTimeSeriesError(e);
                 }
             }
         }

src/OpenCensus.Exporter.Stackdriver/Implementation/StackdriverTraceExporter.cs

@@ -155,7 +155,7 @@ public StackdriverTraceExporter(string projectId)
 
             // Set header mutation for every outgoing API call to Stackdriver so the BE knows
             // which version of OC client is calling it as well as which version of the exporter
-            CallSettings callSettings = CallSettings.FromHeaderMutation(StackDriverCallHeaderAppender);
+            CallSettings callSettings = CallSettings.FromHeaderMutation(StackdriverCallHeaderAppender);
             traceServiceSettings = new TraceServiceSettings();
             traceServiceSettings.CallSettings = callSettings;
         }
@@ -199,7 +199,7 @@ public void Export(IEnumerable<ISpanData> spanDataList)
         /// Appends OpenCensus headers for every outgoing request to Stackdriver Backend
         /// </summary>
         /// <param name="metadata">The metadata that is sent with every outgoing http request</param>
-        private static void StackDriverCallHeaderAppender(Metadata metadata)
+        private static void StackdriverCallHeaderAppender(Metadata metadata)
         {
 
             metadata.Add("AGENT_LABEL_KEY", "g.co/agent");

src/OpenCensus/Implementation/OpenCensusEventSource.cs

@@ -63,7 +63,7 @@ public void FailedReadingEnvironmentVariableWarning(string environmentVariableNa
         }
 
         /// <summary>
-        /// Returns a culture-independent string representation of the given <paramref name="exception"/> object, 
+        /// Returns a culture-independent string representation of the given <paramref name="exception"/> object,
         /// appropriate for diagnostics tracing.
         /// </summary>
         private static string ToInvariantString(Exception exception)