Documentation
¶
Index ¶
- Variables
- func WrapFile(f vfs.File, inj Injector) vfs.File
- type Counter
- type FS
- func (fs *FS) Create(name string, category vfs.DiskWriteCategory) (vfs.File, error)
- func (fs *FS) GetDiskUsage(path string) (vfs.DiskUsage, error)
- func (fs *FS) Link(oldname, newname string) error
- func (fs *FS) List(dir string) ([]string, error)
- func (fs *FS) Lock(name string) (io.Closer, error)
- func (fs *FS) MkdirAll(dir string, perm os.FileMode) error
- func (fs *FS) Open(name string, opts ...vfs.OpenOption) (vfs.File, error)
- func (fs *FS) OpenDir(name string) (vfs.File, error)
- func (fs *FS) OpenReadWrite(name string, category vfs.DiskWriteCategory, opts ...vfs.OpenOption) (vfs.File, error)
- func (fs *FS) PathBase(p string) string
- func (fs *FS) PathDir(p string) string
- func (fs *FS) PathJoin(elem ...string) string
- func (fs *FS) Remove(name string) error
- func (fs *FS) RemoveAll(fullname string) error
- func (fs *FS) Rename(oldname, newname string) error
- func (fs *FS) ReuseForWrite(oldname, newname string, category vfs.DiskWriteCategory) (vfs.File, error)
- func (fs *FS) Stat(name string) (vfs.FileInfo, error)
- func (fs *FS) Unwrap() vfs.FS
- type InjectIndex
- type Injector
- type InjectorFunc
- type LabelledError
- type Op
- type OpKind
- type OpReadWrite
- type Parser
- type Predicate
- type Toggle
Constants ¶
This section is empty.
Variables ¶
var ErrInjected = LabelledError{ Label: "ErrInjected", // contains filtered or unexported fields }
ErrInjected is an error artificially injected for testing fs error paths.
Functions ¶
Types ¶
type Counter ¶
type Counter struct {
Injector
// contains filtered or unexported fields
}
Counter wraps an Injector, counting the number of errors injected. It may be used in tests to ensure that when an error is injected, the error is surfaced through the user interface.
func (*Counter) MaybeError ¶
MaybeError implements Injector.
type FS ¶
type FS struct {
// contains filtered or unexported fields
}
FS implements vfs.FS, injecting errors into its operations.
func Wrap ¶
Wrap wraps an existing vfs.FS implementation, returning a new vfs.FS implementation that shadows operations to the provided FS. It uses the provided Injector for deciding when to inject errors. If an error is injected, FS propagates the error instead of shadowing the operation.
func (*FS) GetDiskUsage ¶
GetDiskUsage implements FS.GetDiskUsage.
func (*FS) OpenReadWrite ¶
func (fs *FS) OpenReadWrite( name string, category vfs.DiskWriteCategory, opts ...vfs.OpenOption, ) (vfs.File, error)
OpenReadWrite implements FS.OpenReadWrite.
func (*FS) ReuseForWrite ¶
func (fs *FS) ReuseForWrite( oldname, newname string, category vfs.DiskWriteCategory, ) (vfs.File, error)
ReuseForWrite implements FS.ReuseForWrite.
type InjectIndex ¶
InjectIndex implements Injector, injecting an error at a specific index.
func OnIndex ¶
func OnIndex(index int32) *InjectIndex
OnIndex is a convenience function for constructing a dsl.OnIndex for use with an error-injecting filesystem.
func (*InjectIndex) MaybeError ¶
func (ii *InjectIndex) MaybeError(op Op) error
MaybeError implements the Injector interface.
TODO(jackson): Remove this implementation and update callers to compose it with other injectors.
type Injector ¶
type Injector interface {
fmt.Stringer
// MaybeError is invoked by an errorfs before an operation is executed. It
// is passed an enum indicating the type of operation and a path of the
// subject file or directory. If the operation takes two paths (eg,
// Rename, Link), the original source path is provided.
MaybeError(op Op) error
}
Injector injects errors into FS operations.
func Any ¶
Any returns an injector that injects an error if any of the provided injectors inject an error. The error returned by the first injector to return an error is used.
func RandomLatency ¶
RandomLatency constructs an Injector that does not inject errors but instead injects random latency into operations that match the provided predicate. The amount of latency injected follows an exponential distribution with the provided mean. Latency injected is derived from the provided seed and is deterministic with respect to each file's path.
If limit is nonzero, total latency injected over the lifetime of the Injector is capped to limit.
type InjectorFunc ¶
InjectorFunc implements the Injector interface for a function with MaybeError's signature.
func (InjectorFunc) MaybeError ¶
func (f InjectorFunc) MaybeError(op Op) error
MaybeError implements the Injector interface.
type LabelledError ¶
type LabelledError struct {
Label string
// contains filtered or unexported fields
}
LabelledError is an error that also implements Injector, unconditionally injecting itself. It implements String() by returning its label. It implements Error() by returning its underlying error.
func (LabelledError) If ¶
func (le LabelledError) If(p Predicate) Injector
If returns an Injector that returns the receiver error if the provided predicate evalutes to true.
func (LabelledError) MaybeError ¶
func (le LabelledError) MaybeError(op Op) error
MaybeError implements Injector.
func (LabelledError) String ¶
func (le LabelledError) String() string
String implements fmt.Stringer.
type Op ¶
type Op struct {
// Kind describes the particular kind of operation being performed.
Kind OpKind
// Path is the path of the file of the file being operated on.
Path string
// Offset is the offset of an operation. It's set for OpFileReadAt and
// OpFileWriteAt operations.
Offset int64
}
Op describes a filesystem operation.
type OpKind ¶
type OpKind int
OpKind is an enum describing the type of operation.
const ( // OpCreate describes a create file operation. OpCreate OpKind = iota // OpLink describes a hardlink operation. OpLink // OpOpen describes a file open operation. OpOpen // OpOpenDir describes a directory open operation. OpOpenDir // OpRemove describes a remove file operation. OpRemove // OpRemoveAll describes a recursive remove operation. OpRemoveAll // OpRename describes a rename operation. OpRename // OpReuseForWrite describes a reuse for write operation. OpReuseForWrite // OpMkdirAll describes a make directory including parents operation. OpMkdirAll // OpLock describes a lock file operation. OpLock // OpList describes a list directory operation. OpList // OpFilePreallocate describes a file preallocate operation. OpFilePreallocate // OpStat describes a path-based stat operation. OpStat // OpGetDiskUsage describes a disk usage operation. OpGetDiskUsage // OpFileClose describes a close file operation. OpFileClose // OpFileRead describes a file read operation. OpFileRead // OpFileReadAt describes a file seek read operation. OpFileReadAt // OpFileWrite describes a file write operation. OpFileWrite // OpFileWriteAt describes a file seek write operation. OpFileWriteAt // OpFileStat describes a file stat operation. OpFileStat // OpFileSync describes a file sync operation. OpFileSync // OpFileSyncData describes a file sync operation. OpFileSyncData // OpFileSyncTo describes a file sync operation. OpFileSyncTo // OpFileFlush describes a file flush operation. OpFileFlush )
func (OpKind) ReadOrWrite ¶
func (o OpKind) ReadOrWrite() OpReadWrite
ReadOrWrite returns the operation's kind.
type OpReadWrite ¶
type OpReadWrite int
OpReadWrite is an enum describing whether an operation is a read or write operation.
const ( // OpIsRead describes read operations. OpIsRead OpReadWrite = iota // OpIsWrite describes write operations. OpIsWrite )
type Parser ¶
type Parser struct {
// contains filtered or unexported fields
}
A Parser parses the error-injecting DSL. It may be extended to include additional errors through AddError.
func NewParser ¶
func NewParser() *Parser
NewParser constructs a new parser for an encoding of a lisp-like DSL describing error injectors.
Errors: - ErrInjected is the only error currently supported by the DSL.
Injectors:
- <ERROR>: An error by itself is an injector that injects an error every time.
- (<ERROR> <PREDICATE>) is an injector that injects an error only when the operation satisfies the predicate.
Predicates:
- Reads is a constant predicate that evalutes to true iff the operation is a read operation (eg, Open, Read, ReadAt, Stat)
- Writes is a constant predicate that evaluates to true iff the operation is a write operation (eg, Create, Rename, Write, WriteAt, etc).
- (PathMatch <STRING>) is a predicate that evalutes to true iff the operation's file path matches the provided shell pattern.
- (OnIndex <INTEGER>) is a predicate that evaluates to true only on the n-th invocation.
- (And <PREDICATE> [PREDICATE]...) is a predicate that evaluates to true iff all the provided predicates evaluate to true. And short circuits on the first predicate to evaluate to false.
- (Or <PREDICATE> [PREDICATE]...) is a predicate that evaluates to true iff at least one of the provided predicates evaluates to true. Or short circuits on the first predicate to evaluate to true.
- (Not <PREDICATE>) is a predicate that evaluates to true iff its provided predicates evaluates to false.
- (Randomly <FLOAT> [INTEGER]) is a predicate that pseudorandomly evaluates to true. The probability of evaluating to true is determined by the required float argument (must be ≤1). The optional second parameter is a pseudorandom seed, for adjusting the deterministic randomness.
- Operation-specific: (OpFileReadAt <INTEGER>) is a predicate that evaluates to true iff an operation is a file ReadAt call with an offset that's exactly equal.
Example: (ErrInjected (And (PathMatch "*.sst") (OnIndex 5))) is a rule set that will inject an error on the 5-th I/O operation involving an sstable.
func (*Parser) AddError ¶
func (p *Parser) AddError(le LabelledError)
AddError defines a new error that may be used within the DSL parsed by Parse and will inject the provided error.
type Predicate ¶
Predicate encodes conditional logic that determines whether to inject an error.
var ( // Reads is a predicate that returns true iff an operation is a read // operation. Reads Predicate = opKindPred{/* contains filtered or unexported fields */} // Writes is a predicate that returns true iff an operation is a write // operation. Writes Predicate = opKindPred{/* contains filtered or unexported fields */} )
func PathMatch ¶
PathMatch returns a predicate that returns true if an operation's file path matches the provided pattern according to filepath.Match.
func Randomly ¶
Randomly constructs a new predicate that pseudorandomly evaluates to true with probability p using randomness determinstically derived from seed.
The predicate is deterministic with respect to file paths: its behavior for a particular file is deterministic regardless of intervening evaluations for operations on other files. This can be used to ensure determinism despite nondeterministic concurrency if the concurrency is constrained to separate files.
type Toggle ¶
type Toggle struct {
Injector
// contains filtered or unexported fields
}
Toggle wraps an Injector. By default, Toggle injects nothing. When toggled on through its On method, it begins injecting errors when the contained injector injects them. It may be returned to its original state through Off.
func (*Toggle) MaybeError ¶
MaybeError implements Injector.
Source Files