Expose Log writer that can be used with external libraries (#22)

* Flinkk8soperator needs Log writer to be passed to

logger/logger.go

@@ -5,6 +5,7 @@ package logger
 
 import (
 	"context"
+	"io"
 
 	"github.com/lyft/flytestdlib/contextutils"
 
@@ -81,6 +82,12 @@ func getLogger(ctx context.Context) logrus.FieldLogger {
 	return entry
 }
 
+// Returns a standard io.PipeWriter that logs using the same logger configurations in this package.
+func GetLogWriter(ctx context.Context) *io.PipeWriter {
+	logger := getLogger(ctx)
+	return logger.(*logrus.Entry).Writer()
+}
+
 func WithIndent(ctx context.Context, additionalIndent string) context.Context {
 	indentLevel := getIndent(ctx) + additionalIndent
 	return context.WithValue(ctx, indentLevelKey, indentLevel)