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|
package housekeeping
import (
"bytes"
"context"
"errors"
"fmt"
"io/fs"
"os"
"path/filepath"
"strings"
"time"
"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus/ctxlogrus"
log "github.com/sirupsen/logrus"
"gitlab.com/gitlab-org/gitaly/v16/internal/git"
"gitlab.com/gitlab-org/gitaly/v16/internal/git/localrepo"
"gitlab.com/gitlab-org/gitaly/v16/internal/gitaly/transaction"
"gitlab.com/gitlab-org/gitaly/v16/internal/safe"
"gitlab.com/gitlab-org/gitaly/v16/internal/structerr"
"gitlab.com/gitlab-org/gitaly/v16/internal/tracing"
"google.golang.org/grpc/codes"
)
const (
emptyRefsGracePeriod = 24 * time.Hour
deleteTempFilesOlderThanDuration = 7 * 24 * time.Hour
brokenRefsGracePeriod = 24 * time.Hour
lockfileGracePeriod = 15 * time.Minute
referenceLockfileGracePeriod = 1 * time.Hour
packedRefsLockGracePeriod = 1 * time.Hour
packedRefsNewGracePeriod = 15 * time.Minute
packFileLockGracePeriod = 7 * 24 * time.Hour
)
var lockfiles = []string{
"config.lock",
"HEAD.lock",
"info/attributes.lock",
"objects/info/alternates.lock",
"objects/info/commit-graphs/commit-graph-chain.lock",
"objects/pack/multi-pack-index.lock",
}
type (
findStaleFileFunc func(context.Context, string) ([]string, error)
cleanupRepoFunc func(context.Context, *localrepo.Repo) (int, error)
cleanupRepoWithTxManagerFunc func(context.Context, *localrepo.Repo, transaction.Manager) (int, error)
)
// CleanStaleDataConfig is the configuration for running CleanStaleData. It is used to define
// the different types of cleanups we want to run.
type CleanStaleDataConfig struct {
staleFileFinders map[string]findStaleFileFunc
repoCleanups map[string]cleanupRepoFunc
repoCleanupWithTxManagers map[string]cleanupRepoWithTxManagerFunc
}
// OnlyStaleReferenceLockCleanup returns a config which only contains a
// stale reference lock cleaner with the provided grace period.
func OnlyStaleReferenceLockCleanup(gracePeriod time.Duration) CleanStaleDataConfig {
return CleanStaleDataConfig{
staleFileFinders: map[string]findStaleFileFunc{
"reflocks": findStaleReferenceLocks(gracePeriod),
},
}
}
// DefaultStaleDataCleanup is the default configuration for CleanStaleData
// which contains all the cleanup functions.
func DefaultStaleDataCleanup() CleanStaleDataConfig {
return CleanStaleDataConfig{
staleFileFinders: map[string]findStaleFileFunc{
"objects": findTemporaryObjects,
"locks": findStaleLockfiles,
"refs": findBrokenLooseReferences,
"reflocks": findStaleReferenceLocks(referenceLockfileGracePeriod),
"packfilelocks": findStalePackFileLocks,
"packedrefslock": findPackedRefsLock,
"packedrefsnew": findPackedRefsNew,
"serverinfo": findServerInfo,
},
repoCleanups: map[string]cleanupRepoFunc{
"refsemptydir": removeRefEmptyDirs,
"configsections": pruneEmptyConfigSections,
},
repoCleanupWithTxManagers: map[string]cleanupRepoWithTxManagerFunc{
"configkeys": removeUnnecessaryConfig,
},
}
}
// CleanStaleData removes any stale data in the repository as per the provided configuration.
func (m *RepositoryManager) CleanStaleData(ctx context.Context, repo *localrepo.Repo, cfg CleanStaleDataConfig) error {
span, ctx := tracing.StartSpanIfHasParent(ctx, "housekeeping.CleanStaleData", nil)
defer span.Finish()
repoPath, err := repo.Path()
if err != nil {
myLogger(ctx).WithError(err).Warn("housekeeping failed to get repo path")
if structerr.GRPCCode(err) == codes.NotFound {
return nil
}
return fmt.Errorf("housekeeping failed to get repo path: %w", err)
}
staleDataByType := map[string]int{}
defer func() {
if len(staleDataByType) == 0 {
return
}
logEntry := myLogger(ctx)
for staleDataType, count := range staleDataByType {
logEntry = logEntry.WithField(fmt.Sprintf("stale_data.%s", staleDataType), count)
m.prunedFilesTotal.WithLabelValues(staleDataType).Add(float64(count))
}
logEntry.Info("removed files")
}()
var filesToPrune []string
for staleFileType, staleFileFinder := range cfg.staleFileFinders {
staleFiles, err := staleFileFinder(ctx, repoPath)
if err != nil {
return fmt.Errorf("housekeeping failed to find %s: %w", staleFileType, err)
}
filesToPrune = append(filesToPrune, staleFiles...)
staleDataByType[staleFileType] = len(staleFiles)
}
for _, path := range filesToPrune {
if err := os.Remove(path); err != nil {
if os.IsNotExist(err) {
continue
}
staleDataByType["failures"]++
myLogger(ctx).WithError(err).WithField("path", path).Warn("unable to remove stale file")
}
}
for repoCleanupName, repoCleanupFn := range cfg.repoCleanups {
cleanupCount, err := repoCleanupFn(ctx, repo)
staleDataByType[repoCleanupName] = cleanupCount
if err != nil {
return fmt.Errorf("housekeeping could not perform cleanup %s: %w", repoCleanupName, err)
}
}
for repoCleanupName, repoCleanupFn := range cfg.repoCleanupWithTxManagers {
cleanupCount, err := repoCleanupFn(ctx, repo, m.txManager)
staleDataByType[repoCleanupName] = cleanupCount
if err != nil {
return fmt.Errorf("housekeeping could not perform cleanup (with TxManager) %s: %w", repoCleanupName, err)
}
}
return nil
}
// pruneEmptyConfigSections prunes all empty sections from the repo's config.
func pruneEmptyConfigSections(ctx context.Context, repo *localrepo.Repo) (_ int, returnedErr error) {
repoPath, err := repo.Path()
if err != nil {
return 0, fmt.Errorf("getting repo path: %w", err)
}
configPath := filepath.Join(repoPath, "config")
// The gitconfig shouldn't ever be big given that we nowadays don't write any unbounded
// values into it anymore. Slurping it into memory should thus be fine.
configContents, err := os.ReadFile(configPath)
if err != nil {
return 0, fmt.Errorf("reading config: %w", err)
}
configLines := strings.SplitAfter(string(configContents), "\n")
if configLines[len(configLines)-1] == "" {
// Strip the last line if it's empty.
configLines = configLines[:len(configLines)-1]
}
skippedSections := 0
// We now filter out any empty sections. A section is empty if the next line is a section
// header as well, or if it is the last line in the gitconfig. This isn't quite the whole
// story given that a section can also be empty if it just ain't got any keys, but only
// comments or whitespace. But we only ever write the gitconfig programmatically, so we
// shouldn't typically see any such cases at all.
filteredLines := make([]string, 0, len(configLines))
for i := 0; i < len(configLines)-1; i++ {
// Skip if we have two consecutive section headers.
if isSectionHeader(configLines[i]) && isSectionHeader(configLines[i+1]) {
skippedSections++
continue
}
filteredLines = append(filteredLines, configLines[i])
}
// The final line is always stripped in case it is a section header.
if len(configLines) > 0 && !isSectionHeader(configLines[len(configLines)-1]) {
skippedSections++
filteredLines = append(filteredLines, configLines[len(configLines)-1])
}
// If we haven't filtered out anything then there is no need to update the target file.
if len(configLines) == len(filteredLines) {
return 0, nil
}
// Otherwise, we need to update the repository's configuration.
configWriter, err := safe.NewLockingFileWriter(configPath)
if err != nil {
return 0, fmt.Errorf("creating config configWriter: %w", err)
}
defer func() {
if err := configWriter.Close(); err != nil && returnedErr == nil {
returnedErr = fmt.Errorf("closing config writer: %w", err)
}
}()
for _, filteredLine := range filteredLines {
if _, err := configWriter.Write([]byte(filteredLine)); err != nil {
return 0, fmt.Errorf("writing filtered config: %w", err)
}
}
// This is a sanity check to assert that we really didn't change anything as seen by
// Git. We run `git config -l` on both old and new file and assert that they report
// the same config entries. Because empty sections are never reported we shouldn't
// see those, and as a result any difference in output is a difference we need to
// worry about.
var configOutputs []string
for _, path := range []string{configPath, configWriter.Path()} {
var configOutput bytes.Buffer
if err := repo.ExecAndWait(ctx, git.Command{
Name: "config",
Flags: []git.Option{
git.ValueFlag{Name: "-f", Value: path},
git.Flag{Name: "-l"},
},
}, git.WithStdout(&configOutput)); err != nil {
return 0, fmt.Errorf("listing config: %w", err)
}
configOutputs = append(configOutputs, configOutput.String())
}
if configOutputs[0] != configOutputs[1] {
return 0, fmt.Errorf("section pruning has caused config change")
}
// We don't use transactional voting but commit the file directly -- we have asserted that
// the change is idempotent anyway.
if err := configWriter.Lock(); err != nil {
return 0, fmt.Errorf("failed locking config: %w", err)
}
if err := configWriter.Commit(); err != nil {
return 0, fmt.Errorf("failed committing pruned config: %w", err)
}
return skippedSections, nil
}
func isSectionHeader(line string) bool {
line = strings.TrimSpace(line)
return strings.HasPrefix(line, "[") && strings.HasSuffix(line, "]")
}
// findStaleFiles determines whether any of the given files rooted at repoPath
// are stale or not. A file is considered stale if it exists and if it has not
// been modified during the gracePeriod. A nonexistent file is not considered
// to be a stale file and will not cause an error.
func findStaleFiles(repoPath string, gracePeriod time.Duration, files ...string) ([]string, error) {
var staleFiles []string
for _, file := range files {
path := filepath.Join(repoPath, file)
fileInfo, err := os.Stat(path)
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, err
}
if time.Since(fileInfo.ModTime()) < gracePeriod {
continue
}
staleFiles = append(staleFiles, path)
}
return staleFiles, nil
}
// findStaleLockfiles finds a subset of lockfiles which may be created by git
// commands. We're quite conservative with what we're removing, we certaintly
// don't just scan the repo for `*.lock` files. Instead, we only remove a known
// set of lockfiles which have caused problems in the past.
func findStaleLockfiles(ctx context.Context, repoPath string) ([]string, error) {
return findStaleFiles(repoPath, lockfileGracePeriod, lockfiles...)
}
// findStalePackFileLocks finds packfile locks (`.keep` files) that git-receive-pack(1) and
// git-fetch-pack(1) write in order to not have the newly written packfile be deleted while refs
// have not yet been updated to point to their objects. Normally, these locks would get removed by
// both Git commands once the refs have been updated. But when the command gets killed meanwhile,
// then it can happen that the locks are left behind. As Git will never delete packfiles with an
// associated `.keep` file, the end result is that we may accumulate more and more of these locked
// packfiles over time.
func findStalePackFileLocks(ctx context.Context, repoPath string) ([]string, error) {
locks, err := filepath.Glob(filepath.Join(repoPath, "objects", "pack", "pack-*.keep"))
if err != nil {
return nil, fmt.Errorf("enumerating .keep files: %w", err)
}
var staleLocks []string
for _, lock := range locks {
lockInfo, err := os.Stat(lock)
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, fmt.Errorf("statting .keep: %w", err)
}
// We use a grace period so that we don't accidentally delete a packfile for a
// concurrent fetch or push.
if time.Since(lockInfo.ModTime()) < packFileLockGracePeriod {
continue
}
contents, err := os.ReadFile(lock)
if err != nil {
if os.IsNotExist(err) {
continue
}
return nil, fmt.Errorf("reading .keep: %w", err)
}
// Git will write either of the following messages into the `.keep` file when
// written by either git-fetch-pack(1) or git-receive-pack(1):
//
// - "fetch-pack $PID on $HOSTNAME"
// - "receive-pack $PID on $HOSTNAME"
//
// This allows us to identify these `.keep` files. We skip over any `.keep` files
// that have an unknown prefix as they might've been written by an admin in order to
// keep certain objects alive, whatever the reason.
if !bytes.HasPrefix(contents, []byte("receive-pack ")) && !bytes.HasPrefix(contents, []byte("fetch-pack ")) {
continue
}
staleLocks = append(staleLocks, lock)
}
return staleLocks, nil
}
func findTemporaryObjects(ctx context.Context, repoPath string) ([]string, error) {
var temporaryObjects []string
if err := filepath.WalkDir(filepath.Join(repoPath, "objects"), func(path string, dirEntry fs.DirEntry, err error) error {
if err != nil {
if errors.Is(err, fs.ErrPermission) || errors.Is(err, fs.ErrNotExist) {
return nil
}
return err
}
// Git will never create temporary directories, but only temporary objects,
// packfiles and packfile indices.
if dirEntry.IsDir() {
return nil
}
isStale, err := isStaleTemporaryObject(dirEntry)
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
return nil
}
return fmt.Errorf("checking for stale temporary object: %w", err)
}
if !isStale {
return nil
}
temporaryObjects = append(temporaryObjects, path)
return nil
}); err != nil {
return nil, fmt.Errorf("walking object directory: %w", err)
}
return temporaryObjects, nil
}
func isStaleTemporaryObject(dirEntry fs.DirEntry) (bool, error) {
// Check the entry's name first so that we can ideally avoid stat'ting the entry.
if !strings.HasPrefix(dirEntry.Name(), "tmp_") {
return false, nil
}
fi, err := dirEntry.Info()
if err != nil {
return false, err
}
if time.Since(fi.ModTime()) <= deleteTempFilesOlderThanDuration {
return false, nil
}
return true, nil
}
func findBrokenLooseReferences(ctx context.Context, repoPath string) ([]string, error) {
var brokenRefs []string
if err := filepath.WalkDir(filepath.Join(repoPath, "refs"), func(path string, dirEntry fs.DirEntry, err error) error {
if err != nil {
if errors.Is(err, fs.ErrPermission) || errors.Is(err, fs.ErrNotExist) {
return nil
}
return err
}
if dirEntry.IsDir() {
return nil
}
fi, err := dirEntry.Info()
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
return nil
}
return fmt.Errorf("statting loose ref: %w", err)
}
// When git crashes or a node reboots, it may happen that it leaves behind empty
// references. These references break various assumptions made by git and cause it
// to error in various circumstances. We thus clean them up to work around the
// issue.
if fi.Size() > 0 || time.Since(fi.ModTime()) < brokenRefsGracePeriod {
return nil
}
brokenRefs = append(brokenRefs, path)
return nil
}); err != nil {
return nil, fmt.Errorf("walking references: %w", err)
}
return brokenRefs, nil
}
// findStaleReferenceLocks provides a function which scans the refdb for stale locks
// and loose references against the provided grace period.
func findStaleReferenceLocks(gracePeriod time.Duration) findStaleFileFunc {
return func(_ context.Context, repoPath string) ([]string, error) {
var staleReferenceLocks []string
if err := filepath.WalkDir(filepath.Join(repoPath, "refs"), func(path string, dirEntry fs.DirEntry, err error) error {
if err != nil {
if errors.Is(err, fs.ErrNotExist) || errors.Is(err, fs.ErrPermission) {
return nil
}
return err
}
if dirEntry.IsDir() {
return nil
}
if !strings.HasSuffix(dirEntry.Name(), ".lock") {
return nil
}
fi, err := dirEntry.Info()
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
return nil
}
return fmt.Errorf("statting reference lock: %w", err)
}
if time.Since(fi.ModTime()) < gracePeriod {
return nil
}
staleReferenceLocks = append(staleReferenceLocks, path)
return nil
}); err != nil {
return nil, fmt.Errorf("walking refs: %w", err)
}
return staleReferenceLocks, nil
}
}
func removeUnnecessaryConfig(ctx context.Context, repository *localrepo.Repo, txManager transaction.Manager) (int, error) {
unnecessaryConfigRegex := "^(http\\..+\\.extraheader|remote\\..+\\.(fetch|mirror|prune|url)|core\\.(commitgraph|sparsecheckout|splitindex))$"
if err := repository.UnsetMatchingConfig(ctx, unnecessaryConfigRegex, txManager); err != nil {
if !errors.Is(err, git.ErrNotFound) {
return 0, fmt.Errorf("housekeeping could not unset unnecessary config lines: %w", err)
}
return 0, nil
}
// If we didn't get an error we know that we've deleted _something_. We just set
// this variable to `1` because we don't count how many keys we have deleted. It's
// probably good enough: we only want to know whether we're still pruning such old
// configuration or not, but typically don't care how many there are so that we know
// when to delete this cleanup of legacy data.
return 1, nil
}
// findPackedRefsLock returns stale lockfiles for the packed-refs file.
func findPackedRefsLock(ctx context.Context, repoPath string) ([]string, error) {
return findStaleFiles(repoPath, packedRefsLockGracePeriod, "packed-refs.lock")
}
// findPackedRefsNew returns stale temporary packed-refs files.
func findPackedRefsNew(ctx context.Context, repoPath string) ([]string, error) {
return findStaleFiles(repoPath, packedRefsNewGracePeriod, "packed-refs.new")
}
// findServerInfo returns files generated by git-update-server-info(1). These files are only
// required to serve Git fetches via the dumb HTTP protocol, which we don't serve at all. It's thus
// safe to remove all of those files without a grace period.
func findServerInfo(ctx context.Context, repoPath string) ([]string, error) {
var serverInfoFiles []string
for directory, basename := range map[string]string{
filepath.Join(repoPath, "info"): "refs",
filepath.Join(repoPath, "objects", "info"): "packs",
} {
entries, err := os.ReadDir(directory)
if err != nil {
if errors.Is(err, os.ErrNotExist) {
continue
}
return nil, fmt.Errorf("reading info directory: %w", err)
}
for _, entry := range entries {
if !entry.Type().IsRegular() {
continue
}
// An exact match is the actual file we care about, while the latter pattern
// refers to the temporary files Git uses to write those files.
if entry.Name() != basename && !strings.HasPrefix(entry.Name(), basename+"_") {
continue
}
serverInfoFiles = append(serverInfoFiles, filepath.Join(directory, entry.Name()))
}
}
return serverInfoFiles, nil
}
func removeRefEmptyDirs(ctx context.Context, repository *localrepo.Repo) (int, error) {
rPath, err := repository.Path()
if err != nil {
return 0, err
}
repoRefsPath := filepath.Join(rPath, "refs")
// we never want to delete the actual "refs" directory, so we start the
// recursive functions for each subdirectory
entries, err := os.ReadDir(repoRefsPath)
if err != nil {
return 0, err
}
prunedDirsTotal := 0
for _, e := range entries {
if !e.IsDir() {
continue
}
prunedDirs, err := removeEmptyDirs(ctx, filepath.Join(repoRefsPath, e.Name()))
if err != nil {
return prunedDirsTotal, err
}
prunedDirsTotal += prunedDirs
}
return prunedDirsTotal, nil
}
func removeEmptyDirs(ctx context.Context, target string) (int, error) {
if err := ctx.Err(); err != nil {
return 0, err
}
// We need to stat the directory early on in order to get its current mtime. If we
// did this after we have removed empty child directories, then its mtime would've
// changed and we wouldn't consider it for deletion.
dirStat, err := os.Stat(target)
if err != nil {
if os.IsNotExist(err) {
return 0, nil
}
return 0, err
}
entries, err := os.ReadDir(target)
switch {
case os.IsNotExist(err):
return 0, nil // race condition: someone else deleted it first
case err != nil:
return 0, err
}
prunedDirsTotal := 0
for _, e := range entries {
if !e.IsDir() {
continue
}
prunedDirs, err := removeEmptyDirs(ctx, filepath.Join(target, e.Name()))
if err != nil {
return prunedDirsTotal, err
}
prunedDirsTotal += prunedDirs
}
// If the directory is older than the grace period for empty refs, then we can
// consider it for deletion in case it's empty.
if time.Since(dirStat.ModTime()) < emptyRefsGracePeriod {
return prunedDirsTotal, nil
}
// recheck entries now that we have potentially removed some dirs
entries, err = os.ReadDir(target)
if err != nil && !os.IsNotExist(err) {
return prunedDirsTotal, err
}
if len(entries) > 0 {
return prunedDirsTotal, nil
}
switch err := os.Remove(target); {
case os.IsNotExist(err):
return prunedDirsTotal, nil // race condition: someone else deleted it first
case err != nil:
return prunedDirsTotal, err
}
return prunedDirsTotal + 1, nil
}
func myLogger(ctx context.Context) *log.Entry {
return ctxlogrus.Extract(ctx).WithField("system", "housekeeping")
}
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