commit 86bf81c0b8a51bffa4b4b566e1caaac6f0e041d3
Author: Sebastien Bourdeauducq <sb@m-labs.hk>
Date:   Thu Mar 14 17:45:32 2019 +0800

    add option to disable retries on transient failures

diff --git a/src/hydra-queue-runner/build-remote.cc b/src/hydra-queue-runner/build-remote.cc
index 69c430eb..bdbc808d 100644
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@@ -344,7 +344,7 @@ void State::buildRemote(ref<Store> destStore,
                     break;
                 case BuildResult::TransientFailure:
                     result.stepStatus = bsFailed;
-                    result.canRetry = true;
+                    result.canRetry = get(step->drv.env, "__hydraRetry", "1") == "1";
                     result.errorMsg = "";
                     break;
                 case BuildResult::TimedOut: