collection

Documentation

Index

• func NewSTM(ctx context.Context, c *v3.Client, apply func(STM) error) (*v3.TxnResponse, error)
• type Collection
  • func NewCollection(etcdClient *etcd.Client, prefix string, indexes []Index, ...) Collection
• type ErrExists
  • func (e ErrExists) Error() string
• type ErrMalformedValue
  • func (e ErrMalformedValue) Error() string
• type ErrNotFound
  • func (e ErrNotFound) Error() string
• type Index
• type Iterator
• type ReadWriteCollection
• type ReadWriteIntCollection
• type ReadonlyCollection
• type STM

Functions

func NewSTM

func NewSTM(ctx context.Context, c *v3.Client, apply func(STM) error) (*v3.TxnResponse, error)

NewSTM intiates a new STM operation. It uses a serializable model.

Types

type Collection

type Collection interface {
	// ReadWrite enables reads and writes on a collection in a
	// transactional manner.  Specifically, all writes are applied
	// atomically, and writes are only applied if reads have not been
	// invalidated at the end of the transaction.  Basically, it's
	// software transactional memory.  See this blog post for details:
	// https://coreos.com/blog/transactional-memory-with-etcd3.html
	ReadWrite(stm STM) ReadWriteCollection
	// ReadWriteInt is the same as ReadWrite except that it operates on
	// integral items, as opposed to protobuf items
	ReadWriteInt(stm STM) ReadWriteIntCollection
	// For read-only operatons, use the ReadOnly for better performance
	ReadOnly(ctx context.Context) ReadonlyCollection
}

Collection implements helper functions that makes common operations on top of etcd more pleasant to work with. It's called collection because most of our data is modelled as collections, such as repos, commits, branches, etc.

func NewCollection

func NewCollection(etcdClient *etcd.Client, prefix string, indexes []Index, template proto.Message) Collection

NewCollection creates a new collection.

type ErrExists

type ErrExists struct {
	Type string
	Key  string
}

ErrExists indicates that a key was found to exist when it was expected not to.

func (ErrExists) Error

func (e ErrExists) Error() string

type ErrMalformedValue

type ErrMalformedValue struct {
	Type string
	Key  string
	Val  string
}

ErrMalformedValue indicates that a value was malformed, such as when it was supposed to be parseable as an int but wasn't.

func (ErrMalformedValue) Error

func (e ErrMalformedValue) Error() string

type ErrNotFound

type ErrNotFound struct {
	Type string
	Key  string
}

ErrNotFound indicates that a key was not found when it was expected to exist.

func (ErrNotFound) Error

func (e ErrNotFound) Error() string

type Index

type Index struct {
	Field string
	Multi bool
}

Index specifies a secondary index on a collection.

Indexes are created in a transactional manner thanks to etcd's transactional support.

A secondary index for collection "foo" on field "bar" will reside under the path `/foo__index_bar`. Each item under the path is in turn a directory whose name is the value of the field `bar`. For instance, if you have a object in collection `foo` whose `bar` field is `test`, then you will see a directory at path `/foo__index_bar/test`.

Under that directory, you have keys that point to items in the collection. For instance, if the aforementioned object has the key "buzz", then you will see an item at `/foo__index_bar/test/buzz`. The value of this item is empty. Thus, to get all items in collection `foo` whose values of field `bar` is `test`, we issue a query for all items under `foo__index_bar/test`.

Multi specifies whether this is a multi-index. A multi-index is an index on a field that's a slice. The item is then indexed on each element of the slice.

type Iterator

type Iterator interface {
	// Next is a function that, when called, serializes the key and value
	// of the next object in a collection.
	// ok is true if the serialization was successful.  It's false if the
	// collection has been exhausted.
	Next(key *string, val proto.Unmarshaler) (ok bool, retErr error)
}

Iterator is an interface for iterating protobufs.

type ReadWriteCollection

type ReadWriteCollection interface {
	Get(key string, val proto.Unmarshaler) error
	Put(key string, val proto.Marshaler)
	Create(key string, val proto.Marshaler) error
	Delete(key string) error
	DeleteAll()
}

ReadWriteCollection is a collection interface that supports read,write and delete operations.

type ReadWriteIntCollection

type ReadWriteIntCollection interface {
	Create(key string, val int) error
	Get(key string) (int, error)
	Increment(key string) error
	Decrement(key string) error
	Delete(key string) error
}

ReadWriteIntCollection is a ReadonlyCollection interface specifically for ints.

type ReadonlyCollection

type ReadonlyCollection interface {
	Get(key string, val proto.Unmarshaler) error
	GetByIndex(index Index, val interface{}) (Iterator, error)
	List() (Iterator, error)
	Watch() (watch.Watcher, error)
	// WatchWithPrev is like Watch, but the events will include the previous
	// versions of the key/value.
	WatchWithPrev() (watch.Watcher, error)
	WatchOne(key string) (watch.Watcher, error)
	WatchByIndex(index Index, val interface{}) (watch.Watcher, error)
}

ReadonlyCollection is a collection interface that only supports read ops.

type STM

type STM interface {
	// Get returns the value for a key and inserts the key in the txn's read set.
	// If Get fails, it aborts the transaction with an error, never returning.
	Get(key string) string
	// Put adds a value for a key to the write set.
	Put(key, val string, opts ...v3.OpOption)
	// Rev returns the revision of a key in the read set.
	Rev(key string) int64
	// Del deletes a key.
	Del(key string)
	// DelAll deletes all keys with the given prefix
	// Note that the current implementation of DelAll is incomplete.
	// To use DelAll safely, do not issue any Get/Put operations after
	// DelAll is called.
	DelAll(key string)
	Context() context.Context
	// contains filtered or unexported methods
}

STM is an interface for software transactional memory.