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Get rid of a tryToBuild tail recursive call with loop

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This will make it easier to convert somethings to RAII.
This commit is contained in:
John Ericson 2025-08-29 13:59:47 -04:00
parent 95c5779880
commit 4c44a213a3
1 changed files with 90 additions and 86 deletions
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176
src/libstore/build/derivation-building-goal.cc
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@ -472,101 +472,105 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
{ {
bool useHook; bool useHook;
trace("trying to build"); while (true) {
trace("trying to build");
/* Obtain locks on all output paths, if the paths are known a priori. /* Obtain locks on all output paths, if the paths are known a priori.
The locks are automatically released when we exit this function or Nix The locks are automatically released when we exit this function or Nix
crashes. If we can't acquire the lock, then continue; hopefully some crashes. If we can't acquire the lock, then continue; hopefully some
other goal can start a build, and if not, the main loop will sleep a few other goal can start a build, and if not, the main loop will sleep a few
seconds and then retry this goal. */ seconds and then retry this goal. */
PathSet lockFiles; PathSet lockFiles;
/* FIXME: Should lock something like the drv itself so we don't build same /* FIXME: Should lock something like the drv itself so we don't build same
CA drv concurrently */ CA drv concurrently */
if (dynamic_cast<LocalStore *>(&worker.store)) { if (dynamic_cast<LocalStore *>(&worker.store)) {
/* If we aren't a local store, we might need to use the local store as /* If we aren't a local store, we might need to use the local store as
a build remote, but that would cause a deadlock. */ a build remote, but that would cause a deadlock. */
/* FIXME: Make it so we can use ourselves as a build remote even if we /* FIXME: Make it so we can use ourselves as a build remote even if we
are the local store (separate locking for building vs scheduling? */ are the local store (separate locking for building vs scheduling? */
/* FIXME: find some way to lock for scheduling for the other stores so /* FIXME: find some way to lock for scheduling for the other stores so
a forking daemon with --store still won't farm out redundant builds. a forking daemon with --store still won't farm out redundant builds.
*/ */
for (auto & i : drv->outputsAndOptPaths(worker.store)) { for (auto & i : drv->outputsAndOptPaths(worker.store)) {
if (i.second.second) if (i.second.second)
lockFiles.insert(worker.store.Store::toRealPath(*i.second.second)); lockFiles.insert(worker.store.Store::toRealPath(*i.second.second));
else else
lockFiles.insert(worker.store.Store::toRealPath(drvPath) + "." + i.first); lockFiles.insert(worker.store.Store::toRealPath(drvPath) + "." + i.first);
}
} }
}
if (!outputLocks.lockPaths(lockFiles, "", false)) { if (!outputLocks.lockPaths(lockFiles, "", false)) {
Activity act(*logger, lvlWarn, actBuildWaiting, fmt("waiting for lock on %s", Magenta(showPaths(lockFiles)))); Activity act(
*logger, lvlWarn, actBuildWaiting, fmt("waiting for lock on %s", Magenta(showPaths(lockFiles))));
/* Wait then try locking again, repeat until success (returned /* Wait then try locking again, repeat until success (returned
boolean is true). */ boolean is true). */
do { do {
co_await waitForAWhile(); co_await waitForAWhile();
} while (!outputLocks.lockPaths(lockFiles, "", false)); } while (!outputLocks.lockPaths(lockFiles, "", false));
} }
/* Now check again whether the outputs are valid. This is because /* Now check again whether the outputs are valid. This is because
another process may have started building in parallel. After another process may have started building in parallel. After
it has finished and released the locks, we can (and should) it has finished and released the locks, we can (and should)
reuse its results. (Strictly speaking the first check can be reuse its results. (Strictly speaking the first check can be
omitted, but that would be less efficient.) Note that since we omitted, but that would be less efficient.) Note that since we
now hold the locks on the output paths, no other process can now hold the locks on the output paths, no other process can
build this derivation, so no further checks are necessary. */ build this derivation, so no further checks are necessary. */
auto [allValid, validOutputs] = checkPathValidity(); auto [allValid, validOutputs] = checkPathValidity();
if (buildMode != bmCheck && allValid) { if (buildMode != bmCheck && allValid) {
debug("skipping build of derivation '%s', someone beat us to it", worker.store.printStorePath(drvPath)); debug("skipping build of derivation '%s', someone beat us to it", worker.store.printStorePath(drvPath));
outputLocks.setDeletion(true); outputLocks.setDeletion(true);
outputLocks.unlock();
co_return doneSuccess(BuildResult::AlreadyValid, std::move(validOutputs));
}
/* If any of the outputs already exist but are not valid, delete
them. */
for (auto & [_, status] : initialOutputs) {
if (!status.known || status.known->isValid())
continue;
auto storePath = status.known->path;
debug("removing invalid path '%s'", worker.store.printStorePath(status.known->path));
deletePath(worker.store.Store::toRealPath(storePath));
}
/* Don't do a remote build if the derivation has the attribute
`preferLocalBuild' set. Also, check and repair modes are only
supported for local builds. */
bool buildLocally =
(buildMode != bmNormal || drvOptions->willBuildLocally(worker.store, *drv)) && settings.maxBuildJobs.get() != 0;
if (buildLocally) {
useHook = false;
} else {
switch (tryBuildHook()) {
case rpAccept:
/* Yes, it has started doing so. Wait until we get
EOF from the hook. */
useHook = true;
break;
case rpPostpone:
/* Not now; wait until at least one child finishes or
the wake-up timeout expires. */
if (!actLock)
actLock = std::make_unique<Activity>(
*logger,
lvlWarn,
actBuildWaiting,
fmt("waiting for a machine to build '%s'", Magenta(worker.store.printStorePath(drvPath))));
outputLocks.unlock(); outputLocks.unlock();
co_await waitForAWhile(); co_return doneSuccess(BuildResult::AlreadyValid, std::move(validOutputs));
co_return tryToBuild();
case rpDecline:
/* We should do it ourselves. */
useHook = false;
break;
} }
/* If any of the outputs already exist but are not valid, delete
them. */
for (auto & [_, status] : initialOutputs) {
if (!status.known || status.known->isValid())
continue;
auto storePath = status.known->path;
debug("removing invalid path '%s'", worker.store.printStorePath(status.known->path));
deletePath(worker.store.Store::toRealPath(storePath));
}
/* Don't do a remote build if the derivation has the attribute
`preferLocalBuild' set. Also, check and repair modes are only
supported for local builds. */
bool buildLocally = (buildMode != bmNormal || drvOptions->willBuildLocally(worker.store, *drv))
&& settings.maxBuildJobs.get() != 0;
if (buildLocally) {
useHook = false;
} else {
switch (tryBuildHook()) {
case rpAccept:
/* Yes, it has started doing so. Wait until we get
EOF from the hook. */
useHook = true;
break;
case rpPostpone:
/* Not now; wait until at least one child finishes or
the wake-up timeout expires. */
if (!actLock)
actLock = std::make_unique<Activity>(
*logger,
lvlWarn,
actBuildWaiting,
fmt("waiting for a machine to build '%s'", Magenta(worker.store.printStorePath(drvPath))));
outputLocks.unlock();
co_await waitForAWhile();
continue;
case rpDecline:
/* We should do it ourselves. */
useHook = false;
break;
}
}
break;
} }
actLock.reset(); actLock.reset();