Add WorkflowInfo.WorkflowStartTime (#476)

Fixes #462

Author: cretz

src/Temporalio/Worker/WorkflowInstance.cs

@@ -198,6 +198,7 @@ public WorkflowInstance(WorkflowInstanceDetails details)
                 TaskQueue: details.TaskQueue,
                 TaskTimeout: start.WorkflowTaskTimeout.ToTimeSpan(),
                 WorkflowId: start.WorkflowId,
+                WorkflowStartTime: start.StartTime.ToDateTime(),
                 WorkflowType: start.WorkflowType);
             workflowStackTrace = details.WorkflowStackTrace;
             pendingTaskStackTraces = workflowStackTrace == WorkflowStackTrace.None ? null : new();

src/Temporalio/Workflows/WorkflowInfo.cs

@@ -23,10 +23,11 @@ namespace Temporalio.Workflows
     /// versions or if there is no root (i.e. the root is itself).</param>
     /// <param name="RunId">Run ID for the workflow.</param>
     /// <param name="RunTimeout">Run timeout for the workflow.</param>
-    /// <param name="StartTime">Time when the workflow started.</param>
+    /// <param name="StartTime">Time when the first workflow task started.</param>
     /// <param name="TaskQueue">Task queue for the workflow.</param>
     /// <param name="TaskTimeout">Task timeout for the workflow.</param>
     /// <param name="WorkflowId">ID for the workflow.</param>
+    /// <param name="WorkflowStartTime">Time when the workflow started on the server.</param>
     /// <param name="WorkflowType">Workflow type name.</param>
     /// <remarks>
     /// WARNING: This constructor may have required properties added. Do not rely on the exact
@@ -51,6 +52,7 @@ public record WorkflowInfo(
         string TaskQueue,
         TimeSpan TaskTimeout,
         string WorkflowId,
+        DateTime WorkflowStartTime,
         string WorkflowType)
     {
         /// <summary>

tests/Temporalio.Tests/Worker/WorkflowWorkerTests.cs

@@ -390,6 +390,7 @@ await ExecuteWorkerAsync<InfoWorkflow>(async worker =>
                 (InfoWorkflow wf) => wf.RunAsync(),
                 new(id: $"workflow-{Guid.NewGuid()}", taskQueue: worker.Options.TaskQueue!));
             var result = await handle.GetResultAsync();
+            var history = await handle.FetchHistoryAsync();
             Assert.Equal(1, result.Attempt);
             Assert.Null(result.ContinuedRunId);
             Assert.Null(result.CronSchedule);
@@ -400,15 +401,19 @@ await ExecuteWorkerAsync<InfoWorkflow>(async worker =>
             Assert.Null(result.Root);
             Assert.Equal(handle.ResultRunId, result.RunId);
             Assert.Null(result.RunTimeout);
-            Assert.InRange(
-                result.StartTime,
-                DateTime.UtcNow - TimeSpan.FromMinutes(5),
-                DateTime.UtcNow + TimeSpan.FromMinutes(5));
             Assert.Equal(worker.Options.TaskQueue, result.TaskQueue);
             // TODO(cretz): Can assume default 10 in all test servers?
             Assert.Equal(TimeSpan.FromSeconds(10), result.TaskTimeout);
             Assert.Equal(handle.Id, result.WorkflowId);
             Assert.Equal("InfoWorkflow", result.WorkflowType);
+            // Start time is the first task start time, but workflow start time is the actual start
+            // time
+            var workflowStartTime = history.Events.
+                Single(e => e.WorkflowExecutionStartedEventAttributes != null).EventTime.ToDateTime();
+            Assert.Equal(workflowStartTime, result.WorkflowStartTime);
+            var firstTaskStartTime = history.Events.
+                First(e => e.WorkflowTaskStartedEventAttributes != null).EventTime.ToDateTime();
+            Assert.Equal(firstTaskStartTime, result.StartTime);
         });
         // Child info
         await ExecuteWorkerAsync<InfoFromChildWorkflow>(