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-rw-r--r--third_party/nix/src/build-remote/build-remote.cc283
1 files changed, 283 insertions, 0 deletions
diff --git a/third_party/nix/src/build-remote/build-remote.cc b/third_party/nix/src/build-remote/build-remote.cc
new file mode 100644
index 000000000000..2802b49ac8ea
--- /dev/null
+++ b/third_party/nix/src/build-remote/build-remote.cc
@@ -0,0 +1,283 @@
+#include <algorithm>
+#include <cstdlib>
+#include <cstring>
+#include <iomanip>
+#include <memory>
+#include <set>
+#include <tuple>
+
+#include <glog/logging.h>
+#if __APPLE__
+#include <sys/time.h>
+#endif
+
+#include "derivations.hh"
+#include "globals.hh"
+#include "legacy.hh"
+#include "local-store.hh"
+#include "machines.hh"
+#include "pathlocks.hh"
+#include "serialise.hh"
+#include "shared.hh"
+#include "store-api.hh"
+
+using namespace nix;
+using std::cin;
+
+static void handleAlarm(int sig) {}
+
+std::string escapeUri(std::string uri) {
+  std::replace(uri.begin(), uri.end(), '/', '_');
+  return uri;
+}
+
+static string currentLoad;
+
+static AutoCloseFD openSlotLock(const Machine& m, unsigned long long slot) {
+  return openLockFile(fmt("%s/%s-%d", currentLoad, escapeUri(m.storeUri), slot),
+                      true);
+}
+
+static bool allSupportedLocally(const std::set<std::string>& requiredFeatures) {
+  for (auto& feature : requiredFeatures) {
+    if (settings.systemFeatures.get().count(feature) == 0u) {
+      return false;
+    }
+  }
+  return true;
+}
+
+static int _main(int argc, char* argv[]) {
+  {
+    /* Ensure we don't get any SSH passphrase or host key popups. */
+    unsetenv("DISPLAY");
+    unsetenv("SSH_ASKPASS");
+
+    if (argc != 2) {
+      throw UsageError("called without required arguments");
+    }
+
+    FdSource source(STDIN_FILENO);
+
+    /* Read the parent's settings. */
+    while (readInt(source) != 0u) {
+      auto name = readString(source);
+      auto value = readString(source);
+      settings.set(name, value);
+    }
+
+    settings.maxBuildJobs.set("1");  // hack to make tests with local?root= work
+
+    initPlugins();
+
+    auto store = openStore().cast<LocalStore>();
+
+    /* It would be more appropriate to use $XDG_RUNTIME_DIR, since
+       that gets cleared on reboot, but it wouldn't work on macOS. */
+    currentLoad = store->stateDir + "/current-load";
+
+    std::shared_ptr<Store> sshStore;
+    AutoCloseFD bestSlotLock;
+
+    auto machines = getMachines();
+    DLOG(INFO) << "got " << machines.size() << " remote builders";
+
+    if (machines.empty()) {
+      std::cerr << "# decline-permanently\n";
+      return 0;
+    }
+
+    string drvPath;
+    string storeUri;
+
+    while (true) {
+      try {
+        auto s = readString(source);
+        if (s != "try") {
+          return 0;
+        }
+      } catch (EndOfFile&) {
+        return 0;
+      }
+
+      auto amWilling = readInt(source);
+      auto neededSystem = readString(source);
+      source >> drvPath;
+      auto requiredFeatures = readStrings<std::set<std::string>>(source);
+
+      auto canBuildLocally =
+          (amWilling != 0u) &&
+          (neededSystem == settings.thisSystem ||
+           settings.extraPlatforms.get().count(neededSystem) > 0) &&
+          allSupportedLocally(requiredFeatures);
+
+      /* Error ignored here, will be caught later */
+      mkdir(currentLoad.c_str(), 0777);
+
+      while (true) {
+        bestSlotLock = -1;
+        AutoCloseFD lock = openLockFile(currentLoad + "/main-lock", true);
+        lockFile(lock.get(), ltWrite, true);
+
+        bool rightType = false;
+
+        Machine* bestMachine = nullptr;
+        unsigned long long bestLoad = 0;
+        for (auto& m : machines) {
+          DLOG(INFO) << "considering building on remote machine '" << m.storeUri
+                     << "'";
+
+          if (m.enabled &&
+              std::find(m.systemTypes.begin(), m.systemTypes.end(),
+                        neededSystem) != m.systemTypes.end() &&
+              m.allSupported(requiredFeatures) &&
+              m.mandatoryMet(requiredFeatures)) {
+            rightType = true;
+            AutoCloseFD free;
+            unsigned long long load = 0;
+            for (unsigned long long slot = 0; slot < m.maxJobs; ++slot) {
+              auto slotLock = openSlotLock(m, slot);
+              if (lockFile(slotLock.get(), ltWrite, false)) {
+                if (!free) {
+                  free = std::move(slotLock);
+                }
+              } else {
+                ++load;
+              }
+            }
+            if (!free) {
+              continue;
+            }
+            bool best = false;
+            if (!bestSlotLock) {
+              best = true;
+            } else if (load / m.speedFactor <
+                       bestLoad / bestMachine->speedFactor) {
+              best = true;
+            } else if (load / m.speedFactor ==
+                       bestLoad / bestMachine->speedFactor) {
+              if (m.speedFactor > bestMachine->speedFactor) {
+                best = true;
+              } else if (m.speedFactor == bestMachine->speedFactor) {
+                if (load < bestLoad) {
+                  best = true;
+                }
+              }
+            }
+            if (best) {
+              bestLoad = load;
+              bestSlotLock = std::move(free);
+              bestMachine = &m;
+            }
+          }
+        }
+
+        if (!bestSlotLock) {
+          if (rightType && !canBuildLocally) {
+            std::cerr << "# postpone\n";
+          } else {
+            std::cerr << "# decline\n";
+          }
+          break;
+        }
+
+#if __APPLE__
+        futimes(bestSlotLock.get(), NULL);
+#else
+        futimens(bestSlotLock.get(), nullptr);
+#endif
+
+        lock = -1;
+
+        try {
+          DLOG(INFO) << "connecting to '" << bestMachine->storeUri << "'";
+
+          Store::Params storeParams;
+          if (hasPrefix(bestMachine->storeUri, "ssh://")) {
+            storeParams["max-connections"] = "1";
+            storeParams["log-fd"] = "4";
+            if (!bestMachine->sshKey.empty()) {
+              storeParams["ssh-key"] = bestMachine->sshKey;
+            }
+          }
+
+          sshStore = openStore(bestMachine->storeUri, storeParams);
+          sshStore->connect();
+          storeUri = bestMachine->storeUri;
+
+        } catch (std::exception& e) {
+          auto msg = chomp(drainFD(5, false));
+          LOG(ERROR) << "cannot build on '" << bestMachine->storeUri
+                     << "': " << e.what() << (msg.empty() ? "" : ": " + msg);
+          bestMachine->enabled = false;
+          continue;
+        }
+
+        goto connected;
+      }
+    }
+
+  connected:
+    close(5);
+
+    std::cerr << "# accept\n" << storeUri << "\n";
+
+    auto inputs = readStrings<PathSet>(source);
+    auto outputs = readStrings<PathSet>(source);
+
+    AutoCloseFD uploadLock = openLockFile(
+        currentLoad + "/" + escapeUri(storeUri) + ".upload-lock", true);
+
+    {
+      DLOG(INFO) << "waiting for the upload lock to '" << storeUri << "'";
+
+      auto old = signal(SIGALRM, handleAlarm);
+      alarm(15 * 60);
+      if (!lockFile(uploadLock.get(), ltWrite, true)) {
+        LOG(ERROR) << "somebody is hogging the upload lock, continuing...";
+      }
+      alarm(0);
+      signal(SIGALRM, old);
+    }
+
+    auto substitute =
+        settings.buildersUseSubstitutes ? Substitute : NoSubstitute;
+
+    {
+      DLOG(INFO) << "copying dependencies to '" << storeUri << "'";
+      copyPaths(store, ref<Store>(sshStore), inputs, NoRepair, NoCheckSigs,
+                substitute);
+    }
+
+    uploadLock = -1;
+
+    BasicDerivation drv(
+        readDerivation(store->realStoreDir + "/" + baseNameOf(drvPath)));
+    drv.inputSrcs = inputs;
+
+    auto result = sshStore->buildDerivation(drvPath, drv);
+
+    if (!result.success()) {
+      throw Error("build of '%s' on '%s' failed: %s", drvPath, storeUri,
+                  result.errorMsg);
+    }
+
+    PathSet missing;
+    for (auto& path : outputs) {
+      if (!store->isValidPath(path)) {
+        missing.insert(path);
+      }
+    }
+
+    if (!missing.empty()) {
+      DLOG(INFO) << "copying outputs from '" << storeUri << "'";
+      store->locksHeld.insert(missing.begin(), missing.end()); /* FIXME: ugly */
+      copyPaths(ref<Store>(sshStore), store, missing, NoRepair, NoCheckSigs,
+                NoSubstitute);
+    }
+
+    return 0;
+  }
+}
+
+static RegisterLegacyCommand s1("build-remote", _main);