kvstore

package
v0.36.9-crescendo-RC2-... Latest Latest
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 Go to latest Published: Aug 5, 2024 License: AGPL-3.0 Imports: 11 Imported by: 1

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Index

Constants

This section is empty.

Variables

View Source 
var ErrIncompatibleVersionChange = errors.New("incompatible version change when replicating the Protocol State's kvstore")

ErrIncompatibleVersionChange is a sentinel returned when we attempt to replicate a parent KV store snapshot into a snapshot with the specified `protocolVersion` but such operation is not supported by the parent snapshot.

View Source 
var ErrInvalidActivationView = errors.New("invalid activation view for the new Protocol State version")

ErrInvalidActivationView is a sentinel returned when we attempt to process a KV store update, which has an activation candidateView `V` so that `CurrentView + SafetyBuffer < V` does NOT hold.

View Source 
var ErrInvalidUpgradeVersion = errors.New("invalid upgrade version for the Protocol State's kvstore")

ErrInvalidUpgradeVersion is a sentinel returned when we attempt to set a new kvstore version via a ProtocolStateVersionUpgrade event, but the new version is not strictly greater than the current version. This error happens when smart contract has different understanding of the protocol state version than the node software.

View Source 
var ErrInvalidValue = errors.New("invalid value for the requested key in Protocol State's kvstore")

ErrInvalidValue is a sentinel returned when a value is not considered valid for a given key. This sentinel is applicable on a key-by-key basis: same value can be considered valid/invalid for different keys.

View Source 
var ErrKeyNotSet = errors.New("no value for requested key in Protocol State's kvstore")

ErrKeyNotSet is a sentinel returned when a key is queried and no value has been set. The key must exist in the currently active key-value store version. This sentinel is used to communicate an empty/unset value rather than using zero or nil values. This sentinel is applicable on a key-by-key basis: some keys will always have a value set, others will support unset values.

View Source 
var ErrKeyNotSupported = errors.New("protocol state's kvstore does not support the specified key at this version")

ErrKeyNotSupported is a sentinel returned when a key is read or written, but the key does not exist in the currently active version of the key-value store. This can happen in two circumstances, for example:

  1. Current model is v2, software supports v3, and we query a key which was newly added in v3.
  2. Current model is v3 and we query a key which was added in v2 then removed in v3
View Source 
var ErrUnsupportedVersion = errors.New("unsupported version for the Protocol State's kvstore")

ErrUnsupportedVersion is a sentinel returned when we attempt to decode a key-value store instance, but provide an unsupported version. This could happen if we accept an already-encoded key-value store instance from an external source (should be avoided in general) or if the node software version is downgraded.

Functions

func NewDefaultKVStore 

func NewDefaultKVStore(finalizationSafetyThreshold, epochExtensionViewCount uint64, epochStateID flow.Identifier) (protocol_state.KVStoreAPI, error)

NewDefaultKVStore constructs a default Key-Value Store of the *latest* protocol version for bootstrapping. Currently, the KV store is largely empty. TODO: Shortcut in bootstrapping; we will probably have to start with a non-empty KV store in the future; Potentially we may need to carry over the KVStore during a spork (with possible migrations).

func NewKVStoreV0 

func NewKVStoreV0(finalizationSafetyThreshold, epochExtensionViewCount uint64, epochStateID flow.Identifier) (protocol_state.KVStoreAPI, error)

NewKVStoreV0 constructs a KVStore using the v0 model. This is used to test version upgrades, from v0 to v1.

func VersionedDecode 

func VersionedDecode(version uint64, bz []byte) (protocol_state.KVStoreAPI, error)

VersionedDecode decodes a serialized key-value store instance with the given version. Errors:

  • ErrUnsupportedVersion if input version is not supported

Types

type Modelv0 

type Modelv0 struct {
	UpgradableModel
	EpochStateID               flow.Identifier
	EpochExtensionViewCount    uint64
	EpochCommitSafetyThreshold uint64
}

Modelv0 is v0 of the Protocol State key-value store. This model version is not intended to ever be the latest version supported by any software version. Since it is important that the store support managing different model version, this is here so that we can test the implementation with multiple supported KV model versions from the beginning.

func (*Modelv0) GetEpochCommitSafetyThreshold added in v0.37.1 

func (model *Modelv0) GetEpochCommitSafetyThreshold() uint64

func (*Modelv0) GetEpochExtensionViewCount added in v0.37.1 

func (model *Modelv0) GetEpochExtensionViewCount() uint64

GetEpochExtensionViewCount returns the number of views for a hypothetical epoch extension. Note that this value can change at runtime (through a service event). When a new extension is added, the view count is used right at this point in the protocol state's evolution. In other words, different extensions can have different view counts.

func (*Modelv0) GetEpochStateID 

func (model *Modelv0) GetEpochStateID() flow.Identifier

GetEpochStateID returns the state ID of the epoch state. This is part of the most basic model and is used to commit the epoch state to the KV store.

func (*Modelv0) GetProtocolStateVersion 

func (model *Modelv0) GetProtocolStateVersion() uint64

GetProtocolStateVersion returns the version of the Protocol State Snapshot that is backing the `Reader` interface. It is the protocol version that originally created the Protocol State Snapshot. Changes in the protocol state version correspond to changes in the set of key-value pairs which are supported, and which model is used for serialization.

func (*Modelv0) ID 

func (model *Modelv0) ID() flow.Identifier

ID returns an identifier for this key-value store snapshot by hashing internal fields and version number.

func (*Modelv0) Replicate 

func (model *Modelv0) Replicate(protocolVersion uint64) (protocol_state.KVStoreMutator, error)

Replicate instantiates a Protocol State Snapshot of the given `protocolVersion`. It clones existing snapshot and performs a migration if `protocolVersion = 1`. Expected errors during normal operations:

  • ErrIncompatibleVersionChange if replicating the Parent Snapshot into a Snapshot with the specified `protocolVersion` is not supported.

func (*Modelv0) SetEpochExtensionViewCount added in v0.37.1 

func (model *Modelv0) SetEpochExtensionViewCount(viewCount uint64) error

SetEpochExtensionViewCount sets the number of views for a hypothetical epoch extension. Expected errors during normal operations:

  • kvstore.ErrInvalidValue - if the view count is less than FinalizationSafetyThreshold*2.

func (*Modelv0) SetEpochStateID 

func (model *Modelv0) SetEpochStateID(id flow.Identifier)

SetEpochStateID sets the state ID of the epoch state. This method is used to commit the epoch state to the KV store when the state of the epoch is updated.

func (*Modelv0) VersionedEncode 

func (model *Modelv0) VersionedEncode() (uint64, []byte, error)

VersionedEncode encodes the key-value store, returning the version separately from the encoded bytes. No errors are expected during normal operation.

type Modelv1 

type Modelv1 struct {
	Modelv0
}

Modelv1 is v1 of the Protocol State key-value store. This represents the first model version which will be considered "latest" by any deployed software version.

func (*Modelv1) GetProtocolStateVersion 

func (model *Modelv1) GetProtocolStateVersion() uint64

GetProtocolStateVersion returns the version of the Protocol State Snapshot that is backing the `Reader` interface. It is the protocol version that originally created the Protocol State Snapshot. Changes in the protocol state version correspond to changes in the set of key-value pairs which are supported, and which model is used for serialization.

func (*Modelv1) ID 

func (model *Modelv1) ID() flow.Identifier

ID returns an identifier for this key-value store snapshot by hashing internal fields and version number.

func (*Modelv1) Replicate 

func (model *Modelv1) Replicate(protocolVersion uint64) (protocol_state.KVStoreMutator, error)

Replicate instantiates a Protocol State Snapshot of the given `protocolVersion`. It clones existing snapshot if `protocolVersion = 1`, other versions are not supported yet. Expected errors during normal operations:

  • ErrIncompatibleVersionChange if replicating the Parent Snapshot into a Snapshot with the specified `protocolVersion` is not supported.

func (*Modelv1) VersionedEncode 

func (model *Modelv1) VersionedEncode() (uint64, []byte, error)

VersionedEncode encodes the key-value store, returning the version separately from the encoded bytes. No errors are expected during normal operation.

type PSVersionUpgradeStateMachine 

type PSVersionUpgradeStateMachine struct {
	// contains filtered or unexported fields
}

PSVersionUpgradeStateMachine encapsulates the logic for evolving the version of the Protocol State. Specifically, it consumes ProtocolStateVersionUpgrade ServiceEvent that are sealed by the candidate block (possibly still under construction) with the given view. Each relevant event is validated before it is applied to the KV store. All updates are applied to a copy of parent KV store, so parent KV store is not modified. A separate instance should be created for each block to process the updates therein.

func NewPSVersionUpgradeStateMachine 

func NewPSVersionUpgradeStateMachine(
	candidateView uint64,
	parentState protocol.KVStoreReader,
	mutator protocol_state.KVStoreMutator,
) *PSVersionUpgradeStateMachine

NewPSVersionUpgradeStateMachine creates a new state machine to update a specific sub-state of the KV Store. It schedules protocol state version upgrades upon receiving a `ProtocolStateVersionUpgrade` event. The actual model upgrade is handled in the upper layer (`ProtocolStateMachine`).

func (*PSVersionUpgradeStateMachine) Build 

func (m *PSVersionUpgradeStateMachine) Build() (*transaction.DeferredBlockPersist, error)

Build is a no-op, because scheduled version upgrades are stored in the KVStore only, which the caller `protocol.MutableProtocolState` persist. (There is no secondary database operations to index or persist version upgrade data separately)

func (*PSVersionUpgradeStateMachine) EvolveState 

func (m *PSVersionUpgradeStateMachine) EvolveState(orderedUpdates []flow.ServiceEvent) error

EvolveState applies the state change(s) on sub-state P for the candidate block (under construction). Implementation processes only relevant service events and ignores all other events. No errors are expected during normal operations.

func (*PSVersionUpgradeStateMachine) ParentState 

func (m *PSVersionUpgradeStateMachine) ParentState() protocol.KVStoreReader

ParentState returns parent state associated with this state machine.

func (*PSVersionUpgradeStateMachine) View 

func (m *PSVersionUpgradeStateMachine) View() uint64

View returns the view associated with this state machine. The view of the state machine equals the view of the block carrying the respective updates.

type PSVersionUpgradeStateMachineFactory 

type PSVersionUpgradeStateMachineFactory struct {
}

PSVersionUpgradeStateMachineFactory is a factory for creating PSVersionUpgradeStateMachine instances.

func NewPSVersionUpgradeStateMachineFactory 

func NewPSVersionUpgradeStateMachineFactory() *PSVersionUpgradeStateMachineFactory

func (*PSVersionUpgradeStateMachineFactory) Create 

func (f *PSVersionUpgradeStateMachineFactory) Create(candidateView uint64, parentBlockID flow.Identifier, parentState protocol.KVStoreReader, mutator protocol_state.KVStoreMutator) (protocol_state.KeyValueStoreStateMachine, error)

Create instantiates a new PSVersionUpgradeStateMachine, which processes ProtocolStateVersionUpgrade ServiceEvent that are sealed by the candidate block (possibly still under construction) with the given view. No errors are expected during normal operations.

type ProtocolKVStore 

type ProtocolKVStore struct {
	storage.ProtocolKVStore
}

ProtocolKVStore persists different snapshots of key-value stores [KV-stores]. Here, we augment the low-level primitives provided by `storage.ProtocolKVStore` with logic for encoding and decoding the state snapshots into abstract representation `protocol_state.KVStoreAPI`.

TODO (optional): include a cache of the _decoded_ Protocol States, so we don't decode+encode on each consensus view (hot-path)

func NewProtocolKVStore 

func NewProtocolKVStore(protocolStateSnapshots storage.ProtocolKVStore) *ProtocolKVStore

NewProtocolKVStore instantiates a ProtocolKVStore for querying & storing deserialized `protocol_state.KVStoreAPIs`. At this abstraction level, we can only handle protocol state snapshots, whose data models are supported by the current software version. There might be serialized snapshots with legacy versions in the database, that are not supported anymore by this software version and can only be retrieved as versioned binary blobs via `storage.ProtocolKVStore`.

func (*ProtocolKVStore) ByBlockID 

func (p *ProtocolKVStore) ByBlockID(blockID flow.Identifier) (protocol_state.KVStoreAPI, error)

ByBlockID retrieves the kv-store snapshot that the block with the given ID proposes. CAUTION: this store snapshot requires confirmation by a QC and will only become active at the child block, _after_ validating the QC. Protocol convention:

  • Consider block B, whose ingestion might potentially lead to an updated KV store state. For example, the state changes if we seal some execution results emitting specific service events.
  • For the key `blockID`, we use the identity of block B which _proposes_ this updated KV store. As value, the hash of the resulting state at the end of processing B is to be used.
  • CAUTION: The updated state requires confirmation by a QC and will only become active at the child block, _after_ validating the QC.

Expected errors during normal operations:

  • storage.ErrNotFound if no snapshot has been indexed for the given block.
  • ErrUnsupportedVersion if input version is not supported

func (*ProtocolKVStore) ByID 

func (p *ProtocolKVStore) ByID(protocolStateID flow.Identifier) (protocol_state.KVStoreAPI, error)

ByID retrieves the KV store snapshot with the given ID. Expected errors during normal operations:

  • storage.ErrNotFound if no snapshot with the given Identifier is known.
  • ErrUnsupportedVersion if input version is not supported

func (*ProtocolKVStore) StoreTx 

func (p *ProtocolKVStore) StoreTx(stateID flow.Identifier, kvStore protocol.KVStoreReader) func(*transaction.Tx) error

StoreTx returns an anonymous function (intended to be executed as part of a badger transaction), which persists the given KV-store snapshot as part of a DB tx. Per convention, all implementations of `protocol.KVStoreReader` must support encoding their state into a version and data blob. Expected errors of the returned anonymous function:

  • storage.ErrAlreadyExists if a KV-store snapshot with the given id is already stored.

type UpgradableModel 

type UpgradableModel struct {
	VersionUpgrade *protocol.ViewBasedActivator[uint64]
}

UpgradableModel is a utility struct that must be embedded in all model versions to provide a common interface for managing protocol version upgrades.

func (*UpgradableModel) GetVersionUpgrade 

func (model *UpgradableModel) GetVersionUpgrade() *protocol.ViewBasedActivator[uint64]

GetVersionUpgrade returns the upgrade version of protocol. VersionUpgrade is a view-based activator that specifies the version which has to be applied and the view from which it has to be applied. It may return the current protocol version with a past view if the upgrade has already been activated.

func (*UpgradableModel) SetVersionUpgrade 

func (model *UpgradableModel) SetVersionUpgrade(activator *protocol.ViewBasedActivator[uint64])

SetVersionUpgrade sets the protocol upgrade version. This method is used to update the Protocol State version when a flow.ProtocolStateVersionUpgrade is processed. It contains the new version and the view at which it has to be applied.

Source Files

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