Fix nix log with CA derivations

Fix #6209

When trying to run `nix log <installable>`, try first to resolve the derivation pointed to
by `<installable>` as it is the resolved one that holds the build log.

This has a couple of shortcomings:
1. It’s expensive as it requires re-reading the derivation
2. It’s brittle because if the derivation doesn’t exist anymore or can’t
   be resolved (which is the case if any one of its build inputs is missing),
   then we can’t access the log anymore

However, I don’t think we can do better (at least not right now).
The alternatives I see are:
1. Copy the build log for the un-resolved derivation. But that means a
   lot of duplication
2. Store the results of the resolving in the db. Which might be the best
   long-term solution, but leads to a whole new class of potential
   issues.
This commit is contained in:
regnat 2022-03-08 06:02:25 +01:00 committed by Taeer Bar-Yam
parent 1dd7779c7c
commit 04b113f6cb
7 changed files with 59 additions and 82 deletions

View file

@ -504,18 +504,10 @@ void BinaryCacheStore::addSignatures(const StorePath & storePath, const StringSe
std::optional<std::string> BinaryCacheStore::getBuildLog(const StorePath & path)
{
auto drvPath = path;
if (!path.isDerivation()) {
try {
auto info = queryPathInfo(path);
// FIXME: add a "Log" field to .narinfo
if (!info->deriver) return std::nullopt;
drvPath = *info->deriver;
} catch (InvalidPath &) {
return std::nullopt;
}
}
auto maybePath = getBuildDerivationPath(path);
if (!maybePath)
return std::nullopt;
auto drvPath = maybePath.value();
auto logPath = "log/" + std::string(baseNameOf(printStorePath(drvPath)));

View file

@ -89,17 +89,10 @@ const std::string LocalFSStore::drvsLogDir = "drvs";
std::optional<std::string> LocalFSStore::getBuildLog(const StorePath & path_)
{
auto path = path_;
if (!path.isDerivation()) {
try {
auto info = queryPathInfo(path);
if (!info->deriver) return std::nullopt;
path = *info->deriver;
} catch (InvalidPath &) {
return std::nullopt;
}
}
auto maybePath = getBuildDerivationPath(path_);
if (!maybePath)
return std::nullopt;
auto path = maybePath.value();
auto baseName = path.to_string();

View file

@ -1300,6 +1300,34 @@ Derivation readDerivationCommon(Store& store, const StorePath& drvPath, bool req
}
}
std::optional<StorePath> Store::getBuildDerivationPath(const StorePath & path)
{
if (!path.isDerivation()) {
try {
auto info = queryPathInfo(path);
if (!info->deriver) return std::nullopt;
return *info->deriver;
} catch (InvalidPath &) {
return std::nullopt;
}
}
if (!settings.isExperimentalFeatureEnabled(Xp::CaDerivations) || !isValidPath(path))
return path;
auto drv = readDerivation(path);
if (!derivationHasKnownOutputPaths(drv.type())) {
// The build log is actually attached to the corresponding
// resolved derivation, so we need to get it first
auto resolvedDrv = drv.tryResolve(*this);
if (resolvedDrv)
return writeDerivation(*this, *resolvedDrv, NoRepair, true);
}
return path;
}
Derivation Store::readDerivation(const StorePath & drvPath)
{ return readDerivationCommon(*this, drvPath, true); }

View file

@ -618,6 +618,13 @@ public:
*/
StorePathSet exportReferences(const StorePathSet & storePaths, const StorePathSet & inputPaths);
/**
* Given a store path, return the realisation actually used in the realisation of this path:
* - If the path is a content-addressed derivation, try to resolve it
* - Otherwise, find one of its derivers
*/
std::optional<StorePath> getBuildDerivationPath(const StorePath &);
/* Hack to allow long-running processes like hydra-queue-runner to
occasionally flush their path info cache. */
void clearPathInfoCache()

View file

@ -1,53 +1,6 @@
{ busybox }:
with import ./config.nix;
let
mkDerivation = args:
derivation ({
inherit system;
builder = busybox;
args = ["sh" "-e" args.builder or (builtins.toFile "builder-${args.name}.sh" "if [ -e .attrs.sh ]; then source .attrs.sh; fi; eval \"$buildCommand\"")];
outputHashMode = "recursive";
outputHashAlgo = "sha256";
__contentAddressed = true;
} // removeAttrs args ["builder" "meta"])
// { meta = args.meta or {}; };
input1 = mkDerivation {
shell = busybox;
name = "build-remote-input-1";
buildCommand = "echo FOO > $out";
requiredSystemFeatures = ["foo"];
};
input2 = mkDerivation {
shell = busybox;
name = "build-remote-input-2";
buildCommand = "echo BAR > $out";
requiredSystemFeatures = ["bar"];
};
input3 = mkDerivation {
shell = busybox;
name = "build-remote-input-3";
buildCommand = ''
read x < ${input2}
echo $x BAZ > $out
'';
requiredSystemFeatures = ["baz"];
};
in
mkDerivation {
shell = busybox;
name = "build-remote";
buildCommand =
''
read x < ${input1}
read y < ${input3}
echo "$x $y" > $out
'';
}
import ./build-hook.nix {
inherit busybox;
contentAddressed = true;
}

View file

@ -1,15 +1,22 @@
{ busybox }:
{ busybox, contentAddressed ? false }:
with import ./config.nix;
let
caArgs = if contentAddressed then {
outputHashMode = "recursive";
outputHashAlgo = "sha256";
__contentAddressed = true;
} else {};
mkDerivation = args:
derivation ({
inherit system;
builder = busybox;
args = ["sh" "-e" args.builder or (builtins.toFile "builder-${args.name}.sh" "if [ -e .attrs.sh ]; then source .attrs.sh; fi; eval \"$buildCommand\"")];
} // removeAttrs args ["builder" "meta" "passthru"])
} // removeAttrs args ["builder" "meta" "passthru"]
// caArgs)
// { meta = args.meta or {}; passthru = args.passthru or {}; };
input1 = mkDerivation {

View file

@ -63,12 +63,9 @@ nix path-info --store $TEST_ROOT/machine3 --all \
| grep builder-build-remote-input-3.sh
# Temporarily disabled because of https://github.com/NixOS/nix/issues/6209
if [[ -z "$CONTENT_ADDRESSED" ]]; then
for i in input1 input3; do
nix log --store $TEST_ROOT/machine0 --file "$file" --arg busybox $busybox passthru."$i" | grep hi-$i
done
fi
for i in input1 input3; do
nix log --store $TEST_ROOT/machine0 --file "$file" --arg busybox $busybox passthru."$i" | grep hi-$i
done
# Behavior of keep-failed
out="$(nix-build 2>&1 failing.nix \