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k8s.io/apiserver/pkg/storage

package storage

v0.18.3
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Published: May 20, 2020 | License: Apache-2.0 | Module: k8s.io/apiserver

Overview

Interfaces for database-related operations.

Index

Constants

const (
	ErrCodeKeyNotFound int = iota + 1
	ErrCodeKeyExists
	ErrCodeResourceVersionConflicts
	ErrCodeInvalidObj
	ErrCodeUnreachable
)

Variables

var Everything = SelectionPredicate{
	Label: labels.Everything(),
	Field: fields.Everything(),
}

Everything accepts all objects.

func DefaultClusterScopedAttr

func DefaultClusterScopedAttr(obj runtime.Object) (labels.Set, fields.Set, error)

func DefaultNamespaceScopedAttr

func DefaultNamespaceScopedAttr(obj runtime.Object) (labels.Set, fields.Set, error)

func EverythingFunc

func EverythingFunc(runtime.Object) bool

func FieldIndex

func FieldIndex(field string) string

FiledIndex add prefix for field index.

func IsConflict

func IsConflict(err error) bool

IsConflict returns true if and only if err is a write conflict.

func IsInternalError

func IsInternalError(err error) bool

IsInternalError returns true if and only if err is an InternalError.

func IsInvalidError

func IsInvalidError(err error) bool

IsInvalidError returns true if and only if err is an InvalidError.

func IsInvalidObj

func IsInvalidObj(err error) bool

IsInvalidObj returns true if and only if err is invalid error

func IsNodeExist

func IsNodeExist(err error) bool

IsNodeExist returns true if and only if err is an node already exist error.

func IsNotFound

func IsNotFound(err error) bool

IsNotFound returns true if and only if err is "key" not found error.

func IsTooLargeResourceVersion

func IsTooLargeResourceVersion(err error) bool

IsTooLargeResourceVersion returns true if the error is a TooLargeResourceVersion error.

func IsUnreachable

func IsUnreachable(err error) bool

IsUnreachable returns true if and only if err indicates the server could not be reached.

func LabelIndex

func LabelIndex(label string) string

LabelIndex add prefix for label index.

func NamespaceKeyFunc

func NamespaceKeyFunc(prefix string, obj runtime.Object) (string, error)

func NewTooLargeResourceVersionError

func NewTooLargeResourceVersionError(minimumResourceVersion, currentRevision uint64, retrySeconds int) error

NewTooLargeResourceVersionError returns a timeout error with the given retrySeconds for a request for a minimum resource version that is larger than the largest currently available resource version for a requested resource.

func NoNamespaceKeyFunc

func NoNamespaceKeyFunc(prefix string, obj runtime.Object) (string, error)

func ValidateAllObjectFunc

func ValidateAllObjectFunc(ctx context.Context, obj runtime.Object) error

ValidateAllObjectFunc is a "admit everything" instance of ValidateObjectFunc.

type AttrFunc

type AttrFunc func(obj runtime.Object) (labels.Set, fields.Set, error)

AttrFunc returns label and field sets and the uninitialized flag for List or Watch to match. In any failure to parse given object, it returns error.

func (AttrFunc) WithFieldMutation

func (f AttrFunc) WithFieldMutation(fieldMutator FieldMutationFunc) AttrFunc

type FieldMutationFunc

type FieldMutationFunc func(obj runtime.Object, fieldSet fields.Set) error

FieldMutationFunc allows the mutation of the field selection fields. It is mutating to avoid the extra allocation on this common path

type HighWaterMark

type HighWaterMark int64

HighWaterMark is a thread-safe object for tracking the maximum value seen for some quantity.

func (*HighWaterMark) Update

func (hwm *HighWaterMark) Update(current int64) bool

Update returns true if and only if 'current' is the highest value ever seen.

type IndexerFunc

type IndexerFunc func(obj runtime.Object) string

IndexerFunc is a function that for a given object computes <value of an index> for a particular <index>.

type IndexerFuncs

type IndexerFuncs map[string]IndexerFunc

IndexerFuncs is a mapping from <index name> to function that for a given object computes <value for that index>.

type Interface

type Interface interface {
	// Returns Versioner associated with this interface.
	Versioner() Versioner

	// Create adds a new object at a key unless it already exists. 'ttl' is time-to-live
	// in seconds (0 means forever). If no error is returned and out is not nil, out will be
	// set to the read value from database.
	Create(ctx context.Context, key string, obj, out runtime.Object, ttl uint64) error

	// Delete removes the specified key and returns the value that existed at that spot.
	// If key didn't exist, it will return NotFound storage error.
	Delete(ctx context.Context, key string, out runtime.Object, preconditions *Preconditions, validateDeletion ValidateObjectFunc) error

	// Watch begins watching the specified key. Events are decoded into API objects,
	// and any items selected by 'p' are sent down to returned watch.Interface.
	// resourceVersion may be used to specify what version to begin watching,
	// which should be the current resourceVersion, and no longer rv+1
	// (e.g. reconnecting without missing any updates).
	// If resource version is "0", this interface will get current object at given key
	// and send it in an "ADDED" event, before watch starts.
	Watch(ctx context.Context, key string, resourceVersion string, p SelectionPredicate) (watch.Interface, error)

	// WatchList begins watching the specified key's items. Items are decoded into API
	// objects and any item selected by 'p' are sent down to returned watch.Interface.
	// resourceVersion may be used to specify what version to begin watching,
	// which should be the current resourceVersion, and no longer rv+1
	// (e.g. reconnecting without missing any updates).
	// If resource version is "0", this interface will list current objects directory defined by key
	// and send them in "ADDED" events, before watch starts.
	WatchList(ctx context.Context, key string, resourceVersion string, p SelectionPredicate) (watch.Interface, error)

	// Get unmarshals json found at key into objPtr. On a not found error, will either
	// return a zero object of the requested type, or an error, depending on ignoreNotFound.
	// Treats empty responses and nil response nodes exactly like a not found error.
	// The returned contents may be delayed, but it is guaranteed that they will
	// be have at least 'resourceVersion'.
	Get(ctx context.Context, key string, resourceVersion string, objPtr runtime.Object, ignoreNotFound bool) error

	// GetToList unmarshals json found at key and opaque it into *List api object
	// (an object that satisfies the runtime.IsList definition).
	// The returned contents may be delayed, but it is guaranteed that they will
	// be have at least 'resourceVersion'.
	GetToList(ctx context.Context, key string, resourceVersion string, p SelectionPredicate, listObj runtime.Object) error

	// List unmarshalls jsons found at directory defined by key and opaque them
	// into *List api object (an object that satisfies runtime.IsList definition).
	// The returned contents may be delayed, but it is guaranteed that they will
	// be have at least 'resourceVersion'.
	List(ctx context.Context, key string, resourceVersion string, p SelectionPredicate, listObj runtime.Object) error

	// GuaranteedUpdate keeps calling 'tryUpdate()' to update key 'key' (of type 'ptrToType')
	// retrying the update until success if there is index conflict.
	// Note that object passed to tryUpdate may change across invocations of tryUpdate() if
	// other writers are simultaneously updating it, so tryUpdate() needs to take into account
	// the current contents of the object when deciding how the update object should look.
	// If the key doesn't exist, it will return NotFound storage error if ignoreNotFound=false
	// or zero value in 'ptrToType' parameter otherwise.
	// If the object to update has the same value as previous, it won't do any update
	// but will return the object in 'ptrToType' parameter.
	// If 'suggestion' can contain zero or one element - in such case this can be used as
	// a suggestion about the current version of the object to avoid read operation from
	// storage to get it.
	//
	// Example:
	//
	// s := /* implementation of Interface */
	// err := s.GuaranteedUpdate(
	//     "myKey", &MyType{}, true,
	//     func(input runtime.Object, res ResponseMeta) (runtime.Object, *uint64, error) {
	//       // Before each invocation of the user defined function, "input" is reset to
	//       // current contents for "myKey" in database.
	//       curr := input.(*MyType)  // Guaranteed to succeed.
	//
	//       // Make the modification
	//       curr.Counter++
	//
	//       // Return the modified object - return an error to stop iterating. Return
	//       // a uint64 to alter the TTL on the object, or nil to keep it the same value.
	//       return cur, nil, nil
	//    },
	// )
	GuaranteedUpdate(
		ctx context.Context, key string, ptrToType runtime.Object, ignoreNotFound bool,
		precondtions *Preconditions, tryUpdate UpdateFunc, suggestion ...runtime.Object) error

	// Count returns number of different entries under the key (generally being path prefix).
	Count(key string) (int64, error)
}

Interface offers a common interface for object marshaling/unmarshaling operations and hides all the storage-related operations behind it.

type InternalError

type InternalError struct {
	Reason string
}

InternalError is generated when an error occurs in the storage package, i.e., not from the underlying storage backend (e.g., etcd).

func NewInternalError

func NewInternalError(reason string) InternalError

func NewInternalErrorf

func NewInternalErrorf(format string, a ...interface{}) InternalError

func (InternalError) Error

func (e InternalError) Error() string

type InvalidError

type InvalidError struct {
	Errs field.ErrorList
}

InvalidError is generated when an error caused by invalid API object occurs in the storage package.

func NewInvalidError

func NewInvalidError(errors field.ErrorList) InvalidError

func (InvalidError) Error

func (e InvalidError) Error() string

type MatchValue

type MatchValue struct {
	IndexName string
	Value     string
}

MatchValue defines a pair (<index name>, <value for that index>).

type Preconditions

type Preconditions struct {
	// Specifies the target UID.
	// +optional
	UID *types.UID `json:"uid,omitempty"`
	// Specifies the target ResourceVersion
	// +optional
	ResourceVersion *string `json:"resourceVersion,omitempty"`
}

Preconditions must be fulfilled before an operation (update, delete, etc.) is carried out.

func NewUIDPreconditions

func NewUIDPreconditions(uid string) *Preconditions

NewUIDPreconditions returns a Preconditions with UID set.

func (*Preconditions) Check

func (p *Preconditions) Check(key string, obj runtime.Object) error

type ResponseMeta

type ResponseMeta struct {
	// TTL is the time to live of the node that contained the returned object. It may be
	// zero or negative in some cases (objects may be expired after the requested
	// expiration time due to server lag).
	TTL int64
	// The resource version of the node that contained the returned object.
	ResourceVersion uint64
}

ResponseMeta contains information about the database metadata that is associated with an object. It abstracts the actual underlying objects to prevent coupling with concrete database and to improve testability.

type SelectionPredicate

type SelectionPredicate struct {
	Label               labels.Selector
	Field               fields.Selector
	GetAttrs            AttrFunc
	IndexLabels         []string
	IndexFields         []string
	Limit               int64
	Continue            string
	AllowWatchBookmarks bool
}

SelectionPredicate is used to represent the way to select objects from api storage.

func (*SelectionPredicate) Empty

func (s *SelectionPredicate) Empty() bool

Empty returns true if the predicate performs no filtering.

func (*SelectionPredicate) MatcherIndex

func (s *SelectionPredicate) MatcherIndex() []MatchValue

For any index defined by IndexFields, if a matcher can match only (a subset) of objects that return <value> for a given index, a pair (<index name>, <value>) wil be returned.

func (*SelectionPredicate) Matches

func (s *SelectionPredicate) Matches(obj runtime.Object) (bool, error)

Matches returns true if the given object's labels and fields (as returned by s.GetAttrs) match s.Label and s.Field. An error is returned if s.GetAttrs fails.

func (*SelectionPredicate) MatchesObjectAttributes

func (s *SelectionPredicate) MatchesObjectAttributes(l labels.Set, f fields.Set) bool

MatchesObjectAttributes returns true if the given labels and fields match s.Label and s.Field.

func (*SelectionPredicate) MatchesSingle

func (s *SelectionPredicate) MatchesSingle() (string, bool)

MatchesSingle will return (name, true) if and only if s.Field matches on the object's name.

type SimpleUpdateFunc

type SimpleUpdateFunc func(runtime.Object) (runtime.Object, error)

type StorageError

type StorageError struct {
	Code               int
	Key                string
	ResourceVersion    int64
	AdditionalErrorMsg string
}

func NewInvalidObjError

func NewInvalidObjError(key, msg string) *StorageError

func NewKeyExistsError

func NewKeyExistsError(key string, rv int64) *StorageError

func NewKeyNotFoundError

func NewKeyNotFoundError(key string, rv int64) *StorageError

func NewResourceVersionConflictsError

func NewResourceVersionConflictsError(key string, rv int64) *StorageError

func NewUnreachableError

func NewUnreachableError(key string, rv int64) *StorageError

func (*StorageError) Error

func (e *StorageError) Error() string

type UpdateFunc

type UpdateFunc func(input runtime.Object, res ResponseMeta) (output runtime.Object, ttl *uint64, err error)

Pass an UpdateFunc to Interface.GuaranteedUpdate to make an update that is guaranteed to succeed. See the comment for GuaranteedUpdate for more details.

func SimpleUpdate

func SimpleUpdate(fn SimpleUpdateFunc) UpdateFunc

SimpleUpdateFunc converts SimpleUpdateFunc into UpdateFunc

type ValidateObjectFunc

type ValidateObjectFunc func(ctx context.Context, obj runtime.Object) error

ValidateObjectFunc is a function to act on a given object. An error may be returned if the hook cannot be completed. The function may NOT transform the provided object.

type Versioner

type Versioner interface {
	// UpdateObject sets storage metadata into an API object. Returns an error if the object
	// cannot be updated correctly. May return nil if the requested object does not need metadata
	// from database.
	UpdateObject(obj runtime.Object, resourceVersion uint64) error
	// UpdateList sets the resource version into an API list object. Returns an error if the object
	// cannot be updated correctly. May return nil if the requested object does not need metadata from
	// database. continueValue is optional and indicates that more results are available if the client
	// passes that value to the server in a subsequent call. remainingItemCount indicates the number
	// of remaining objects if the list is partial. The remainingItemCount field is omitted during
	// serialization if it is set to nil.
	UpdateList(obj runtime.Object, resourceVersion uint64, continueValue string, remainingItemCount *int64) error
	// PrepareObjectForStorage should set SelfLink and ResourceVersion to the empty value. Should
	// return an error if the specified object cannot be updated.
	PrepareObjectForStorage(obj runtime.Object) error
	// ObjectResourceVersion returns the resource version (for persistence) of the specified object.
	// Should return an error if the specified object does not have a persistable version.
	ObjectResourceVersion(obj runtime.Object) (uint64, error)

	// ParseResourceVersion takes a resource version argument and
	// converts it to the storage backend. For watch we should pass to helper.Watch().
	// Because resourceVersion is an opaque value, the default watch
	// behavior for non-zero watch is to watch the next value (if you pass
	// "1", you will see updates from "2" onwards).
	ParseResourceVersion(resourceVersion string) (uint64, error)
}

Versioner abstracts setting and retrieving metadata fields from database response onto the object ot list. It is required to maintain storage invariants - updating an object twice with the same data except for the ResourceVersion and SelfLink must be a no-op. A resourceVersion of type uint64 is a 'raw' resourceVersion, intended to be sent directly to or from the backend. A resourceVersion of type string is a 'safe' resourceVersion, intended for consumption by users.

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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