README
¶
SafeLock
SafeLock is a golang package for locking files used by distributed services.
Use SafeLock when distributed processes act on the same file on a local or remote filesystem and require exclusive access to that file. SafeLock should not be used to protect access in non-distributed systems as better mechanisms exist.
To use this module add import "github.com/deptofdefense/safelock" to your package.
Example
To use the lock in AWS S3 you could use this code:
svcS3 := s3.NewFromConfig(cfg)
bucket := "bucket"
key := "key"
kmsKeyArn := "kmsKeyArn"
l := safelock.NewS3ObjectLock(bucket, key, kmsKeyArn, &svcS3)
// Wait for the lock to become available
l.WaitForLock()
// Lock the object and defer unlocking
l.Lock()
defer l.Unlock()
// Do work on the object that was locked
This can also be accomplished with a local filesystem:
fs := afero.NewOsFs()
filename := "file.txt"
l := safelock.NewFileLock(filename, fs)
SafeLock also provides a primitive to build your own lock named SafeLock.
Testing
Testing can be done using the Makefile targets make test and make test_coverage.
Development
Development for this has been geared towards MacOS users. Install dependencies to get started:
brew install circleci go golangci-lint pre-commit shellcheck
Install the pre-commit hooks and run them before making pull requests:
pre-commit install
pre-commit run -a
License
This project constitutes a work of the United States Government and is not subject to domestic copyright protection under 17 USC § 105. However, because the project utilizes code licensed from contributors and other third parties, it therefore is licensed under the MIT License. See LICENSE file for more information.
Documentation
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Index ¶
- type FileLock
- type LockS3Client
- type LockState
- type S3ObjectLock
- func (l *S3ObjectLock) GetLockPath() string
- func (l *S3ObjectLock) GetLockState() (LockState, error)
- func (l *S3ObjectLock) GetLockURI() string
- func (l *S3ObjectLock) GetObjectURI() string
- func (l *S3ObjectLock) GetS3Bucket() string
- func (l *S3ObjectLock) GetS3KMSKeyArn() string
- func (l *S3ObjectLock) GetS3Key() string
- func (l *S3ObjectLock) Lock() error
- func (l *S3ObjectLock) Unlock() error
- func (l *S3ObjectLock) WaitForLock() error
- type SafeLock
- func (l *SafeLock) GetID() string
- func (l *SafeLock) GetLockState() (LockState, error)
- func (l *SafeLock) GetLockSuffix() string
- func (l *SafeLock) GetLockURI() string
- func (l *SafeLock) GetTimeout() time.Duration
- func (l *SafeLock) Lock() error
- func (l *SafeLock) SetID(lockID string) error
- func (l *SafeLock) SetLockSuffix(lockSuffix string)
- func (l *SafeLock) SetTimeout(timeout time.Duration)
- func (l *SafeLock) Unlock() error
- func (l *SafeLock) WaitForLock() error
- type SafeLockiface
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type FileLock ¶
type FileLock struct {
*SafeLock
// contains filtered or unexported fields
}
FileLock will create a lock for a specific file As an example, if the URI is file:///filename.txt then the lock will be a file named file:///filename.txt.lock and the contents will be the lock's UUID.
func NewFileLock ¶
NewFileLock creates a new instance of FileLock
func (*FileLock) GetFilename ¶
GetFilename will return the filename for the lock
func (*FileLock) GetLockFilename ¶
GetLockFilename will return the filename for the lock object
func (*FileLock) GetLockState ¶
GetLockState returns the lock's state
func (*FileLock) WaitForLock ¶
WaitForLock waits until an object is no longer locked or cancels based on a timeout
type LockS3Client ¶
type LockS3Client interface {
DeleteObject(ctx context.Context, params *s3.DeleteObjectInput, optFns ...func(*s3.Options)) (*s3.DeleteObjectOutput, error)
GetObject(ctx context.Context, params *s3.GetObjectInput, optFns ...func(*s3.Options)) (*s3.GetObjectOutput, error)
HeadObject(ctx context.Context, params *s3.HeadObjectInput, optFns ...func(*s3.Options)) (*s3.HeadObjectOutput, error)
PutObject(ctx context.Context, params *s3.PutObjectInput, optFns ...func(*s3.Options)) (*s3.PutObjectOutput, error)
}
LockS3Client implements the interface required by S3 for the lock functions
type LockState ¶
type LockState string
const ( // LockStateLocked is the locked state LockStateLocked LockState = "locked" // LockStateUnlocked is the unlocked state LockStateUnlocked LockState = "unlocked" // LockStateUnknown is the unknown lock state LockStateUnknown LockState = "unknown" // DefaultTimeout is the default timeout used for locks DefaultTimeout time.Duration = 30 * time.Second // DefaultSuffix is the default lock suffix used for locks DefaultSuffix = ".lock" )
type S3ObjectLock ¶
type S3ObjectLock struct {
*SafeLock
// contains filtered or unexported fields
}
S3ObjectLock will create a lock for a specific bucket/key combination As an example, if the URI is s3://s3Bucket/s3Key then the lock will be a file named s3://s3Bucket/s3Key.lock and the contents will be the lock's UUID.
func NewS3ObjectLock ¶
func NewS3ObjectLock(s3bucket, s3key, s3KMSKeyArn string, svcS3 LockS3Client) *S3ObjectLock
NewS3ObjectLock creates a new instance of S3ObjectLock
func (*S3ObjectLock) GetLockPath ¶
func (l *S3ObjectLock) GetLockPath() string
GetLockPath will return the s3 key for the lock object
func (*S3ObjectLock) GetLockState ¶
func (l *S3ObjectLock) GetLockState() (LockState, error)
GetLockState returns the lock's state
func (*S3ObjectLock) GetLockURI ¶
func (l *S3ObjectLock) GetLockURI() string
GetLockURI will return the s3 object URI for the lock object
func (*S3ObjectLock) GetObjectURI ¶
func (l *S3ObjectLock) GetObjectURI() string
GetS3ObjectURI will return the s3 object URI for the file being locked
func (*S3ObjectLock) GetS3Bucket ¶
func (l *S3ObjectLock) GetS3Bucket() string
GetS3Bucket will return the s3 bucket for the lock
func (*S3ObjectLock) GetS3KMSKeyArn ¶
func (l *S3ObjectLock) GetS3KMSKeyArn() string
GetS3KMSKeyArn will return the s3 KMS key Arn for the lock
func (*S3ObjectLock) GetS3Key ¶
func (l *S3ObjectLock) GetS3Key() string
GetS3Key will return the s3 key for the lock
func (*S3ObjectLock) WaitForLock ¶
func (l *S3ObjectLock) WaitForLock() error
WaitForLock waits until an object is no longer locked or cancels based on a timeout
type SafeLock ¶
type SafeLock struct {
// contains filtered or unexported fields
}
SafeLock manages the internal locking and metadata for locks
func (*SafeLock) GetLockState ¶
GetLockState returns the lock's state
func (*SafeLock) GetLockSuffix ¶
GetLockSuffix returns the lock suffix being used
func (*SafeLock) GetLockURI ¶
GetLockURI will return the URI for the lock object
func (*SafeLock) GetTimeout ¶
GetTimeout returns the timeout being used
func (*SafeLock) SetLockSuffix ¶
SetLockSuffix sets the lock suffix to use
func (*SafeLock) SetTimeout ¶
SetTimeout sets the timeout to use
func (*SafeLock) WaitForLock ¶
WaitForLock waits until an object is no longer locked or cancels based on a timeout
type SafeLockiface ¶
type SafeLockiface interface {
Lock() error
Unlock() error
GetID() string
SetID(string) error
GetLockState() (LockState, error)
GetLockURI() string
GetLockSuffix() string
SetLockSuffix(string)
GetTimeout() time.Duration
SetTimeout(time.Duration)
WaitForLock() error
}
SafeLockiface is an interface for all implementations of locks
Source Files
Directories