Merge pull request #53 from chanzuckerberg/edu/file-after-event

Read the arbitrary fields file _after_ the command instead of before to allow the command to use it to add additional data to the command span itself.

cmd_cmd.go

@@ -50,7 +50,6 @@ will be launched via "bash -c" using "exec".`,
 			defer ev.Send()
 
 			providerInfo(*ciProvider, ev)
-			arbitraryFields(*filename, ev)
 
 			spanBytes := make([]byte, 16)
 			rand.Read(spanBytes)
@@ -59,6 +58,10 @@ will be launched via "bash -c" using "exec".`,
 			err := runCommand(subcmd)
 			dur := time.Since(start)
 
+			// Annotate with arbitrary fields after the command runs
+			// this way we can consume a file if the command itself generated one
+			arbitraryFields(*filename, ev)
+
 			ev.Add(map[string]interface{}{
 				"trace.parent_id": stepID,
 				"trace.span_id":   fmt.Sprintf("%x", spanBytes),