Make the use of substitutes on builders configurable

doc/manual/src/configuration.md

@@ -74,6 +74,28 @@ following:
         }
     }
 
+Queue Runner configuration
+--------------------------
+
+These configuration options are understood by the Hydra Queue Runner.
+
+- `max_unsupported_time` (default `0`) How long to keep unsupported builds in the queue before failing them
+- `max_db_connections` (default `128`) Size of the database connection pool
+- `max_output_size` (default `2<<30`) Maximum size of a build result output before failing the build (only works for remote builds)
+- `max_log_size` (default `64<<20`) Maximum log size for remote builds
+- `store_uri` (default empty) If set to a non-empty string, the store is used for the Hydra
+- `upload_logs_to_binary_cache` (default `false`) Whether to upload logs of finished builds to the store
+- `gc_roots_dir` (default `/nix/var/nix/gcroots/per-user/hydra/hydra-roots`) Directory for Hydra gcroots
+- `use-substitutes` (default `false`) Whether or not to try to substitute builds results from the configured substituters before building
+- `use_substitutes_on_remote_builders` (default `true`) Whether or not to try to substitute builds inputs from the configured substituters on the build machines when copying build inputs
+- `xxx-jobset-repeats` (default empty) Configuration of automated rebuilds for determinism checks. Takes colon-separated values of `project:jobset:repeat` (for example `nixos:trunk-combined:2`)
+
+Deprecated options
+- `store_mode`
+- `binary_cache_dir`
+- `binary_cache_s3_bucket`
+- `binary_cache_secret_key_file`
+
 Statsd Configuration
 --------------------
 

src/hydra-queue-runner/build-remote.cc

@@ -307,7 +307,7 @@ void State::buildRemote(ref<Store> destStore,
                 destStore->computeFSClosure(inputs, closure);
                 copyPaths(*destStore, *localStore, closure, NoRepair, NoCheckSigs, NoSubstitute);
             } else {
-                copyClosureTo(machine->state->sendLock, *destStore, from, to, inputs, true);
+                copyClosureTo(machine->state->sendLock, *destStore, from, to, inputs, useSubstitutesOnRemoteBuilders);
             }
 
             auto now2 = std::chrono::steady_clock::now();

src/hydra-queue-runner/hydra-queue-runner.cc

@@ -829,6 +829,7 @@ void State::run(BuildID buildOne)
     _destStore = storeUri == "" ? localStore : openStore(storeUri);
 
     useSubstitutes = config->getBoolOption("use-substitutes", false);
+    useSubstitutesOnRemoteBuilders = config->getBoolOption("use_substitutes_on_remote_builders", true);
 
     // FIXME: hacky mechanism for configuring determinism checks.
     for (auto & s : tokenizeString<Strings>(config->getStrOption("xxx-jobset-repeats"))) {

src/hydra-queue-runner/state.hh

@@ -321,6 +321,7 @@ private:
     nix::Path hydraData, logDir;
 
     bool useSubstitutes = false;
+    bool useSubstitutesOnRemoteBuilders = false;
 
     /* The queued builds. */
     typedef std::map<BuildID, Build::ptr> Builds;