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https://github.com/versity/versitygw.git
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Radu Berinde
7ae119d654
Problem:
- `posix.New` calls `os.Chdir(rootdir)` and uses cwd-relative paths for
every bucket and object. That is the cheapest way to address files, but
the cwd is process-wide: embedding the gateway (`embedgw`) silently moves
the host program's cwd. In particular, Go unit tests that embed the
gateway can no longer read their test data files by relative path.
Change:
- New `PosixOpts.AbsolutePaths`. When set, `New` leaves the working
directory alone and builds every path from the absolute root; a relative
`VersioningDir`/`SideCarDir` is then resolved against the working
directory rather than the root. The default is unchanged: chdir and
relative paths.
- All bucket and object paths go through new `BucketPath`/`ObjectPath`,
which return the name as-is by default and prefix the root with
`AbsolutePaths`. An absolute "bucket" (the versioning directory
substitution) is passed through unchanged.
- `tmpfile` records the bucket directory path so `link()` and its fallbacks
use the same addressing; `ListBuckets` reads the root through the same
helper.
- `meta.XattrMeta` needs the same root with `AbsolutePaths`. New
`meta.RootDirSetter` interface; `posix.New` calls `WithRootDir` on
storers that implement it in that mode. A zero `XattrMeta` keeps
resolving against the cwd. `SideCar`/`NoMeta` unchanged. A type that
embeds `XattrMeta` inherits a `WithRootDir` that returns a bare
`XattrMeta`, so it needs its own (documented on `RootDirSetter`).
- `DeleteObject` (directory object), `ListParts`, and `UploadPartCopy`
passed filesystem paths where the metadata API expects bucket/object
names; they now pass names, so the sidecar layout is unchanged in both
modes.
- Windows `handleParentDirError` walks up until `filepath.Dir` is a fixed
point, which works for relative and absolute paths.
- scoutfs used cwd-relative bucket/object paths in `CreateBucket`,
`GetObject`, `HeadObject`, `RestoreObject` and the glacier walk; they now
go through `BucketPath`/`ObjectPath`. `scoutfs.New` resolves `rootdir`
before `posix.New` so a relative root no longer reopens `rootdir/rootdir`
after the chdir.
- `isBucketValid` unconditionally rejects names that do not denote a single
entry under the root: `""`, `.`, `..`, names containing a path separator,
and absolute paths. `XattrMeta` rejects `""`, `.` and `..` likewise.
With relative paths `os.Stat("")` and `os.RemoveAll(".")` failed by
accident; with absolute paths they would act on the root directory itself
(reachable with strict bucket names disabled, or via the admin
`change-bucket-owner` endpoint which does not validate `bucket`).
- scoutfs had its own `isBucketValid` whose `validateBucketName` flag was
never set, so it accepted everything. It now delegates to the new exported
`Posix.IsBucketValid`.
- `UploadPartCopy` did not validate the copy source's bucket name (unlike
`CopyObject`); it does now.
- `New` opens the root after validating the versioning and sidecar
directories, so those error paths no longer leak the root handle. The
chdir still happens first, so a relative directory resolves against the
root as before.
Tests:
- New `TestDefaultModeChangesWorkingDirectory` documents the default.
- New `TestRootDirIndependentOfWorkingDirectory`: `AbsolutePaths` with a
relative root from an unrelated cwd, checks cwd is untouched and that
put/get/list/delete, copy, multipart upload with checksums and part copy,
directory-object delete, and invalid bucket names behave correctly under
the root, for both metadata storers.
- New `TestVersioningDirIndependentOfWorkingDirectory`: same setup with a
relative versioning directory; versions land there and not under the
root or cwd.
- New `TestXattrMetaPath` covers cwd-relative and root resolution, absolute
pass-through and the rejected names.
- New `BenchmarkPosix*` benchmarks (small-object head/get/put/list, both
storers, both path modes). The default mode matches `main` within noise
on both Linux and macOS. `AbsolutePaths` costs about 0.2µs (Linux) to
0.4µs (macOS) per path lookup; on Linux (arm64 VM, overlayfs) that is
+2-3% on PutObject and +10-27% on the metadata-heavy small-object
HeadObject/GetObject/ListObjectsV2 with xattr metadata, which is why it
is opt-in.
63 lines
2.8 KiB
Go
63 lines
2.8 KiB
Go
// Copyright 2024 Versity Software
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// This file is licensed under the Apache License, Version 2.0
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// (the "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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package meta
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import "os"
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// MetadataStorer defines the interface for managing metadata.
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// When object == "", the operation is on the bucket.
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type MetadataStorer interface {
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// RetrieveAttribute retrieves the value of a specific attribute for an object or a bucket.
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// Returns the value of the attribute, or an error if the attribute does not exist.
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RetrieveAttribute(f *os.File, bucket, object, attribute string) ([]byte, error)
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// StoreAttribute stores the value of a specific attribute for an object or a bucket.
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// If attribute already exists, new attribute should replace existing.
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// Returns an error if the operation fails.
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StoreAttribute(f *os.File, bucket, object, attribute string, value []byte) error
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// DeleteAttribute removes the value of a specific attribute for an object or a bucket.
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// Returns an error if the operation fails.
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DeleteAttribute(bucket, object, attribute string) error
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// ListAttributes lists all attributes for an object or a bucket.
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// Returns list of attribute names, or an error if the operation fails.
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ListAttributes(bucket, object string) ([]string, error)
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// DeleteAttributes removes all attributes for an object or a bucket.
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// Returns an error if the operation fails.
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DeleteAttributes(bucket, object string) error
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// RenameObject renames all stored metadata from oldObject to newObject
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// within the given bucket. This must be called whenever the data
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// directory for an object is renamed so that metadata stays in sync.
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RenameObject(bucket, oldObject, newObject string) error
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}
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// RootDirSetter is implemented by metadata storers that keep metadata on the
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// bucket and object files themselves and therefore need to know where those
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// files live. A backend that does not change the process working directory
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// to its root calls WithRootDir with the absolute path of the root before
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// using the storer; the returned storer resolves bucket names against that
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// directory instead of the working directory. Storers that keep metadata
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// elsewhere (SideCar, NoMeta) do not implement it.
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//
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// A type that embeds XattrMeta inherits its WithRootDir, which returns a bare
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// XattrMeta and so drops the outer type; such a type must provide its own
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// WithRootDir.
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type RootDirSetter interface {
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WithRootDir(rootdir string) MetadataStorer
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}
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