Staking
Abstract
This paper specifies the Staking module of the Cosmos SDK that was first described in the Cosmos Whitepaper in June 2016.
The module enables Cosmos SDK-based blockchain to support an advanced Proof-of-Stake (PoS) system. In this system, holders of the native staking token of the chain can become validators and can delegate tokens to validators, ultimately determining the effective validator set for the system.
This module is used in the Cosmos Hub, the first Hub in the Cosmos network.
Contents
State
Pool
Pool is used for tracking bonded and not-bonded token supply of the bond denomination.
LastTotalPower
LastTotalPower tracks the total amounts of bonded tokens recorded during the previous end block. Store entries prefixed with "Last" must remain unchanged until EndBlock.
LastTotalPower:
0x12 -> ProtocolBuffer(math.Int)
ValidatorUpdates
ValidatorUpdates contains the validator updates returned to ABCI at the end of every block. The values are overwritten in every block.
ValidatorUpdates
0x61 -> []abci.ValidatorUpdate
UnbondingID
UnbondingID stores the ID of the latest unbonding operation. It enables creating unique IDs for unbonding operations, i.e., UnbondingID is incremented every time a new unbonding operation (validator unbonding, unbonding delegation, redelegation) is initiated.
UnbondingID:
0x37 -> uint64
Params
The staking module stores its params in state with the prefix of 0x51, it can be updated with governance or the address with authority.
Params:
0x51 | ProtocolBuffer(Params)
Validator
Validators can have one of three statuses
Unbonded: The validator is not in the active set. They cannot sign blocks and do not earn rewards. They can receive delegations.Bonded: Once the validator receives sufficient bonded tokens they automatically join the active set duringEndBlockand their status is updated toBonded. They are signing blocks and receiving rewards. They can receive further delegations. They can be slashed for misbehavior. Delegators to this validator who unbond their delegation must wait the duration of the UnbondingTime, a chain-specific param, during which time they are still slashable for offences of the source validator if those offences were committed during the period of time that the tokens were bonded.Unbonding: When a validator leaves the active set, either by choice or due to slashing, jailing or tombstoning, an unbonding of all their delegations begins. All delegations must then wait the UnbondingTime before their tokens are moved to their accounts from theBondedPool.
:::warning Tombstoning is permanent, once tombstoned a validator's consensus key can not be reused within the chain where the tombstoning happened. :::
Validators objects should be primarily stored and accessed by the OperatorAddr, an SDK validator address for the operator of the validator. Two additional indices are maintained per validator object in order to fulfill required lookups for slashing and validator-set updates. A third special index (LastValidatorPower) is also maintained which however remains constant throughout each block, unlike the first two indices which mirror the validator records within a block.
Validators:
0x21 | OperatorAddrLen (1 byte) | OperatorAddr -> ProtocolBuffer(validator)ValidatorsByConsAddr:
0x22 | ConsAddrLen (1 byte) | ConsAddr -> OperatorAddrValidatorsByPower:
0x23 | BigEndian(ConsensusPower) | OperatorAddrLen (1 byte) | OperatorAddr -> OperatorAddrLastValidatorsPower:
0x11 | OperatorAddrLen (1 byte) | OperatorAddr -> ProtocolBuffer(ConsensusPower)ValidatorsByUnbondingID:
0x38 | UnbondingID -> 0x21 | OperatorAddrLen (1 byte) | OperatorAddr
Validators is the primary index - it ensures that each operator can have only one associated validator, where the public key of that validator can change in the future. Delegators can refer to the immutable operator of the validator, without concern for the changing public key.
ValidatorsByUnbondingID is an additional index that enables lookups for validators by the unbonding IDs corresponding to their current unbonding.
ValidatorByConsAddr is an additional index that enables lookups for slashing. When CometBFT reports evidence, it provides the validator address, so this map is needed to find the operator. Note that the ConsAddr corresponds to the address which can be derived from the validator's ConsPubKey.
ValidatorsByPower is an additional index that provides a sorted list of potential validators to quickly determine the current active set. Here ConsensusPower is validator.Tokens/10^6 by default. Note that all validators where Jailed is true are not stored within this index.
LastValidatorsPower is a special index that provides a historical list of the last-block's bonded validators. This index remains constant during a block but is updated during the validator set update process which takes place in EndBlock.
Each validator's state is stored in a Validator struct:
Delegation
Delegations are identified by combining DelegatorAddr (the address of the delegator) with the ValidatorAddr Delegators are indexed in the store as follows:
Delegation:
0x31 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorAddr -> ProtocolBuffer(delegation)
Stake holders may delegate coins to validators; under this circumstance their funds are held in a Delegation data structure. It is owned by one delegator, and is associated with the shares for one validator. The sender of the transaction is the owner of the bond.
Delegator Shares
When one delegates tokens to a Validator, they are issued a number of delegator shares based on a dynamic exchange rate, calculated as follows from the total number of tokens delegated to the validator and the number of shares issued so far:
Shares per Token = validator.TotalShares() / validator.Tokens()
Only the number of shares received is stored on the DelegationEntry. When a delegator then Undelegates, the token amount they receive is calculated from the number of shares they currently hold and the inverse exchange rate:
Tokens per Share = validator.Tokens() / validatorShares()
These Shares are simply an accounting mechanism. They are not a fungible asset. The reason for this mechanism is to simplify the accounting around slashing. Rather than iteratively slashing the tokens of every delegation entry, instead the Validator's total bonded tokens can be slashed, effectively reducing the value of each issued delegator share.
UnbondingDelegation
Shares in a Delegation can be unbonded, but they must for some time exist as an UnbondingDelegation, where shares can be reduced if Byzantine behavior is detected.
UnbondingDelegation are indexed in the store as:
UnbondingDelegation:
0x32 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorAddr -> ProtocolBuffer(unbondingDelegation)UnbondingDelegationsFromValidator:
0x33 | ValidatorAddrLen (1 byte) | ValidatorAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nilUnbondingDelegationByUnbondingId:
0x38 | UnbondingId -> 0x32 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorAddrUnbondingDelegationis used in queries, to lookup all unbonding delegations for a given delegator.
UnbondingDelegationsFromValidator is used in slashing, to lookup all unbonding delegations associated with a given validator that need to be slashed.
UnbondingDelegationByUnbondingId is an additional index that enables lookups for unbonding delegations by the unbonding IDs of the containing unbonding delegation entries.
A UnbondingDelegation object is created every time an unbonding is initiated.
Redelegation
The bonded tokens worth of a Delegation may be instantly redelegated from a source validator to a different validator (destination validator). However when this occurs they must be tracked in a Redelegation object, whereby their shares can be slashed if their tokens have contributed to a Byzantine fault committed by the source validator.
Redelegation are indexed in the store as:
Redelegations:
0x34 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorSrcAddr | ValidatorDstAddr -> ProtocolBuffer(redelegation)RedelegationsBySrc:
0x35 | ValidatorSrcAddrLen (1 byte) | ValidatorSrcAddr | ValidatorDstAddrLen (1 byte) | ValidatorDstAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nilRedelegationsByDst:
0x36 | ValidatorDstAddrLen (1 byte) | ValidatorDstAddr | ValidatorSrcAddrLen (1 byte) | ValidatorSrcAddr | DelegatorAddrLen (1 byte) | DelegatorAddr -> nilRedelegationByUnbondingId:
0x38 | UnbondingId -> 0x34 | DelegatorAddrLen (1 byte) | DelegatorAddr | ValidatorAddrLen (1 byte) | ValidatorSrcAddr | ValidatorDstAddr
Redelegations is used for queries, to lookup all redelegations for a given delegator.
RedelegationsBySrc is used for slashing based on the ValidatorSrcAddr.
RedelegationsByDst is used for slashing based on the ValidatorDstAddr
The first map here is used for queries, to lookup all redelegations for a given delegator. The second map is used for slashing based on the ValidatorSrcAddr, while the third map is for slashing based on the ValidatorDstAddr.
RedelegationByUnbondingId is an additional index that enables lookups for redelegations by the unbonding IDs of the containing redelegation entries.
A redelegation object is created every time a redelegation occurs. To prevent "redelegation hopping" redelegations may not occur under the situation that:
the (re)delegator already has another immature redelegation in progress with a destination to a validator (let's call it
Validator X)and, the (re)delegator is attempting to create a new redelegation where the source validator for this new redelegation is
Validator X.
Queues
All queue objects are sorted by timestamp. The time used within any queue is firstly converted to UTC, rounded to the nearest nanosecond then sorted. The sortable time format used is a slight modification of the RFC3339Nano and uses the format string "2006-01-02T15:04:05.000000000". Notably this format:
right pads all zeros
drops the time zone info (we already use UTC)
In all cases, the stored timestamp represents the maturation time of the queue element.
UnbondingDelegationQueue
For the purpose of tracking progress of unbonding delegations the unbonding delegations queue is kept.
UnbondingDelegation:
0x41 | format(time) -> []DVPair
RedelegationQueue
For the purpose of tracking progress of redelegations the redelegation queue is kept.
RedelegationQueue:
0x42 | format(time) -> []DVVTriplet
ValidatorQueue
For the purpose of tracking progress of unbonding validators the validator queue is kept.
ValidatorQueueTime:
0x43 | format(time) -> []sdk.ValAddress
The stored object by each key is an array of validator operator addresses from which the validator object can be accessed. Typically it is expected that only a single validator record will be associated with a given timestamp however it is possible that multiple validators exist in the queue at the same location.
HistoricalInfo
HistoricalInfo objects are stored and pruned at each block such that the staking keeper persists the n most recent historical info defined by staking module parameter: HistoricalEntries.
At each BeginBlock, the staking keeper will persist the current Header and the Validators that committed the current block in a HistoricalInfo object. The Validators are sorted on their address to ensure that they are in a deterministic order. The oldest HistoricalEntries will be pruned to ensure that there only exist the parameter-defined number of historical entries.
State Transitions
Validators
State transitions in validators are performed on every EndBlock in order to check for changes in the active ValidatorSet.
A validator can be Unbonded, Unbonding or Bonded. Unbonded and Unbonding are collectively called Not Bonded. A validator can move directly between all the states, except for from Bonded to Unbonded.
Not bonded to Bonded
The following transition occurs when a validator's ranking in the ValidatorPowerIndex surpasses that of the LastValidator.
set
validator.StatustoBondedsend the
validator.Tokensfrom theNotBondedTokensto theBondedPoolModuleAccountdelete the existing record from
ValidatorByPowerIndexadd a new updated record to the
ValidatorByPowerIndexupdate the
Validatorobject for this validatorif it exists, delete any
ValidatorQueuerecord for this validator
Bonded to Unbonding
When a validator begins the unbonding process the following operations occur:
send the
validator.Tokensfrom theBondedPoolto theNotBondedTokensModuleAccountset
validator.StatustoUnbondingdelete the existing record from
ValidatorByPowerIndexadd a new updated record to the
ValidatorByPowerIndexupdate the
Validatorobject for this validatorinsert a new record into the
ValidatorQueuefor this validator
Unbonding to Unbonded
A validator moves from unbonding to unbonded when the ValidatorQueue object moves from bonded to unbonded
update the
Validatorobject for this validatorset
validator.StatustoUnbonded
Jail/Unjail
when a validator is jailed it is effectively removed from the CometBFT set. this process may be also be reversed. the following operations occur:
set
Validator.Jailedand update objectif jailed delete record from
ValidatorByPowerIndexif unjailed add record to
ValidatorByPowerIndex
Jailed validators are not present in any of the following stores:
the power store (from consensus power to address)
Delegations
Delegate
When a delegation occurs both the validator and the delegation objects are affected
determine the delegators shares based on tokens delegated and the validator's exchange rate
remove tokens from the sending account
add shares the delegation object or add them to a created validator object
add new delegator shares and update the
Validatorobjecttransfer the
delegation.Amountfrom the delegator's account to theBondedPoolor theNotBondedPoolModuleAccountdepending if thevalidator.StatusisBondedor notdelete the existing record from
ValidatorByPowerIndexadd an new updated record to the
ValidatorByPowerIndex
Begin Unbonding
As a part of the Undelegate and Complete Unbonding state transitions Unbond Delegation may be called.
subtract the unbonded shares from delegator
add the unbonded tokens to an
UnbondingDelegationEntryupdate the delegation or remove the delegation if there are no more shares
if the delegation is the operator of the validator and no more shares exist then trigger a jail validator
update the validator with removed the delegator shares and associated coins
if the validator state is
Bonded, transfer theCoinsworth of the unbonded shares from theBondedPoolto theNotBondedPoolModuleAccountremove the validator if it is unbonded and there are no more delegation shares.
remove the validator if it is unbonded and there are no more delegation shares
get a unique
unbondingIdand map it to theUnbondingDelegationEntryinUnbondingDelegationByUnbondingIdcall the
AfterUnbondingInitiated(unbondingId)hookadd the unbonding delegation to
UnbondingDelegationQueuewith the completion time set toUnbondingTime
Cancel an UnbondingDelegation Entry
UnbondingDelegation EntryWhen a cancel unbond delegation occurs both the validator, the delegation and an UnbondingDelegationQueue state will be updated.
if cancel unbonding delegation amount equals to the
UnbondingDelegationentrybalance, then theUnbondingDelegationentry deleted fromUnbondingDelegationQueue.if the
cancel unbonding delegation amount is less than theUnbondingDelegationentry balance, then theUnbondingDelegationentry will be updated with new balance in theUnbondingDelegationQueue`.cancel
amountis Delegated back to the originalvalidator.
Complete Unbonding
For undelegations which do not complete immediately, the following operations occur when the unbonding delegation queue element matures:
remove the entry from the
UnbondingDelegationobjecttransfer the tokens from the
NotBondedPoolModuleAccountto the delegatorAccount
Begin Redelegation
Redelegations affect the delegation, source and destination validators.
perform an
unbonddelegation from the source validator to retrieve the tokens worth of the unbonded sharesusing the unbonded tokens,
Delegatethem to the destination validatorif the
sourceValidator.StatusisBonded, and thedestinationValidatoris not, transfer the newly delegated tokens from theBondedPoolto theNotBondedPoolModuleAccountotherwise, if the
sourceValidator.Statusis notBonded, and thedestinationValidatorisBonded, transfer the newly delegated tokens from theNotBondedPoolto theBondedPoolModuleAccountrecord the token amount in an new entry in the relevant
Redelegation
From when a redelegation begins until it completes, the delegator is in a state of "pseudo-unbonding", and can still be slashed for infractions that occurred before the redelegation began.
Complete Redelegation
When a redelegations complete the following occurs:
remove the entry from the
Redelegationobject
Slashing
Slash Validator
When a Validator is slashed, the following occurs:
The total
slashAmountis calculated as theslashFactor(a chain parameter) *TokensFromConsensusPower, the total number of tokens bonded to the validator at the time of the infraction.Every unbonding delegation and pseudo-unbonding redelegation such that the infraction occured before the unbonding or redelegation began from the validator are slashed by the
slashFactorpercentage of the initialBalance.Each amount slashed from redelegations and unbonding delegations is subtracted from the total slash amount.
The
remaingSlashAmountis then slashed from the validator's tokens in theBondedPoolorNonBondedPooldepending on the validator's status. This reduces the total supply of tokens.
In the case of a slash due to any infraction that requires evidence to submitted (for example double-sign), the slash occurs at the block where the evidence is included, not at the block where the infraction occured. Put otherwise, validators are not slashed retroactively, only when they are caught.
Slash Unbonding Delegation
When a validator is slashed, so are those unbonding delegations from the validator that began unbonding after the time of the infraction. Every entry in every unbonding delegation from the validator is slashed by slashFactor. The amount slashed is calculated from the InitialBalance of the delegation and is capped to prevent a resulting negative balance. Completed (or mature) unbondings are not slashed.
Slash Redelegation
When a validator is slashed, so are all redelegations from the validator that began after the infraction. Redelegations are slashed by slashFactor. Redelegations that began before the infraction are not slashed. The amount slashed is calculated from the InitialBalance of the delegation and is capped to prevent a resulting negative balance. Mature redelegations (that have completed pseudo-unbonding) are not slashed.
How Shares are calculated
At any given point in time, each validator has a number of tokens, T, and has a number of shares issued, S. Each delegator, i, holds a number of shares, S_i. The number of tokens is the sum of all tokens delegated to the validator, plus the rewards, minus the slashes.
The delegator is entitled to a portion of the underlying tokens proportional to their proportion of shares. So delegator i is entitled to T * S_i / S of the validator's tokens.
When a delegator delegates new tokens to the validator, they receive a number of shares proportional to their contribution. So when delegator j delegates T_j tokens, they receive S_j = S * T_j / T shares. The total number of tokens is now T + T_j, and the total number of shares is S + S_j. js proportion of the shares is the same as their proportion of the total tokens contributed: (S + S_j) / S = (T + T_j) / T.
A special case is the initial delegation, when T = 0 and S = 0, so T_j / T is undefined. For the initial delegation, delegator j who delegates T_j tokens receive S_j = T_j shares. So a validator that hasn't received any rewards and has not been slashed will have T = S.
Messages
In this section we describe the processing of the staking messages and the corresponding updates to the state. All created/modified state objects specified by each message are defined within the state section.
MsgCreateValidator
A validator is created using the MsgCreateValidator message. The validator must be created with an initial delegation from the operator.
This message is expected to fail if:
another validator with this operator address is already registered
another validator with this pubkey is already registered
the initial self-delegation tokens are of a denom not specified as the bonding denom
the commission parameters are faulty, namely:
MaxRateis either > 1 or < 0the initial
Rateis either negative or >MaxRatethe initial
MaxChangeRateis either negative or >MaxRate
the description fields are too large
This message creates and stores the Validator object at appropriate indexes. Additionally a self-delegation is made with the initial tokens delegation tokens Delegation. The validator always starts as unbonded but may be bonded in the first end-block.
MsgEditValidator
The Description, CommissionRate of a validator can be updated using the MsgEditValidator message.
This message is expected to fail if:
the initial
CommissionRateis either negative or >MaxRatethe
CommissionRatehas already been updated within the previous 24 hoursthe
CommissionRateis >MaxChangeRatethe description fields are too large
This message stores the updated Validator object.
MsgDelegate
Within this message the delegator provides coins, and in return receives some amount of their validator's (newly created) delegator-shares that are assigned to Delegation.Shares.
This message is expected to fail if:
the validator does not exist
the
AmountCoinhas a denomination different than one defined byparams.BondDenomthe exchange rate is invalid, meaning the validator has no tokens (due to slashing) but there are outstanding shares
the amount delegated is less than the minimum allowed delegation
If an existing Delegation object for provided addresses does not already exist then it is created as part of this message otherwise the existing Delegation is updated to include the newly received shares.
The delegator receives newly minted shares at the current exchange rate. The exchange rate is the number of existing shares in the validator divided by the number of currently delegated tokens.
The validator is updated in the ValidatorByPower index, and the delegation is tracked in validator object in the Validators index.
It is possible to delegate to a jailed validator, the only difference being it will not be added to the power index until it is unjailed.
MsgUndelegate
The MsgUndelegate message allows delegators to undelegate their tokens from validator.
This message returns a response containing the completion time of the undelegation:
This message is expected to fail if:
the delegation doesn't exist
the validator doesn't exist
the delegation has less shares than the ones worth of
Amountexisting
UnbondingDelegationhas maximum entries as defined byparams.MaxEntriesthe
Amounthas a denomination different than one defined byparams.BondDenom
When this message is processed the following actions occur:
validator's
DelegatorSharesand the delegation'sSharesare both reduced by the messageSharesAmountcalculate the token worth of the shares remove that amount tokens held within the validator
with those removed tokens, if the validator is:
Bonded- add them to an entry inUnbondingDelegation(createUnbondingDelegationif it doesn't exist) with a completion time a full unbonding period from the current time. Update pool shares to reduce BondedTokens and increase NotBondedTokens by token worth of the shares.Unbonding- add them to an entry inUnbondingDelegation(createUnbondingDelegationif it doesn't exist) with the same completion time as the validator (UnbondingMinTime).Unbonded- then send the coins the messageDelegatorAddr
if there are no more
Sharesin the delegation, then the delegation object is removed from the storeunder this situation if the delegation is the validator's self-delegation then also jail the validator.
MsgCancelUnbondingDelegation
The MsgCancelUnbondingDelegation message allows delegators to cancel the unbondingDelegation entry and delegate back to a previous validator.
This message is expected to fail if:
the
unbondingDelegationentry is already processed.the
cancel unbonding delegationamount is greater than theunbondingDelegationentry balance.the
cancel unbonding delegationheight doesn't exist in theunbondingDelegationQueueof the delegator.
When this message is processed the following actions occur:
if the
unbondingDelegationEntry balance is zeroin this condition
unbondingDelegationentry will be removed fromunbondingDelegationQueue.otherwise
unbondingDelegationQueuewill be updated with newunbondingDelegationentry balance and initial balance
the validator's
DelegatorSharesand the delegation'sSharesare both increased by the messageAmount.
MsgBeginRedelegate
The redelegation command allows delegators to instantly switch validators. Once the unbonding period has passed, the redelegation is automatically completed in the EndBlocker.
This message returns a response containing the completion time of the redelegation:
This message is expected to fail if:
the delegation doesn't exist
the source or destination validators don't exist
the delegation has less shares than the ones worth of
Amountthe source validator has a receiving redelegation which is not matured (aka. the redelegation may be transitive)
existing
Redelegationhas maximum entries as defined byparams.MaxEntriesthe
AmountCoinhas a denomination different than one defined byparams.BondDenom
When this message is processed the following actions occur:
the source validator's
DelegatorSharesand the delegationsSharesare both reduced by the messageSharesAmountcalculate the token worth of the shares remove that amount tokens held within the source validator.
if the source validator is:
Bonded- add an entry to theRedelegation(createRedelegationif it doesn't exist) with a completion time a full unbonding period from the current time. Update pool shares to reduce BondedTokens and increase NotBondedTokens by token worth of the shares (this may be effectively reversed in the next step however).Unbonding- add an entry to theRedelegation(createRedelegationif it doesn't exist) with the same completion time as the validator (UnbondingMinTime).Unbonded- no action required in this step
Delegate the token worth to the destination validator, possibly moving tokens back to the bonded state.
if there are no more
Sharesin the source delegation, then the source delegation object is removed from the storeunder this situation if the delegation is the validator's self-delegation then also jail the validator.
MsgUpdateParams
The MsgUpdateParams update the staking module parameters. The params are updated through a governance proposal where the signer is the gov module account address.
The message handling can fail if:
signer is not the authority defined in the staking keeper (usually the gov module account).
Begin-Block
Each abci begin block call, the historical info will get stored and pruned according to the HistoricalEntries parameter.
Historical Info Tracking
If the HistoricalEntries parameter is 0, then the BeginBlock performs a no-op.
Otherwise, the latest historical info is stored under the key historicalInfoKey|height, while any entries older than height - HistoricalEntries is deleted. In most cases, this results in a single entry being pruned per block. However, if the parameter HistoricalEntries has changed to a lower value there will be multiple entries in the store that must be pruned.
End-Block
Each abci end block call, the operations to update queues and validator set changes are specified to execute.
Validator Set Changes
The staking validator set is updated during this process by state transitions that run at the end of every block. As a part of this process any updated validators are also returned back to CometBFT for inclusion in the CometBFT validator set which is responsible for validating CometBFT messages at the consensus layer. Operations are as following:
the new validator set is taken as the top
params.MaxValidatorsnumber of validators retrieved from theValidatorsByPowerindexthe previous validator set is compared with the new validator set:
missing validators begin unbonding and their
Tokensare transferred from theBondedPoolto theNotBondedPoolModuleAccountnew validators are instantly bonded and their
Tokensare transferred from theNotBondedPoolto theBondedPoolModuleAccount
In all cases, any validators leaving or entering the bonded validator set or changing balances and staying within the bonded validator set incur an update message reporting their new consensus power which is passed back to CometBFT.
The LastTotalPower and LastValidatorsPower hold the state of the total power and validator power from the end of the last block, and are used to check for changes that have occurred in ValidatorsByPower and the total new power, which is calculated during EndBlock.
Queues
Within staking, certain state-transitions are not instantaneous but take place over a duration of time (typically the unbonding period). When these transitions are mature certain operations must take place in order to complete the state operation. This is achieved through the use of queues which are checked/processed at the end of each block.
Unbonding Validators
When a validator is kicked out of the bonded validator set (either through being jailed, or not having sufficient bonded tokens) it begins the unbonding process along with all its delegations begin unbonding (while still being delegated to this validator). At this point the validator is said to be an "unbonding validator", whereby it will mature to become an "unbonded validator" after the unbonding period has passed.
Each block the validator queue is to be checked for mature unbonding validators (namely with a completion time <= current time and completion height <= current block height). At this point any mature validators which do not have any delegations remaining are deleted from state. For all other mature unbonding validators that still have remaining delegations, the validator.Status is switched from types.Unbonding to types.Unbonded.
Unbonding operations can be put on hold by external modules via the PutUnbondingOnHold(unbondingId) method. As a result, an unbonding operation (e.g., an unbonding delegation) that is on hold, cannot complete even if it reaches maturity. For an unbonding operation with unbondingId to eventually complete (after it reaches maturity), every call to PutUnbondingOnHold(unbondingId) must be matched by a call to UnbondingCanComplete(unbondingId).
Unbonding Delegations
Complete the unbonding of all mature UnbondingDelegations.Entries within the UnbondingDelegations queue with the following procedure:
transfer the balance coins to the delegator's wallet address
remove the mature entry from
UnbondingDelegation.Entriesremove the
UnbondingDelegationobject from the store if there are no remaining entries.
Redelegations
Complete the unbonding of all mature Redelegation.Entries within the Redelegations queue with the following procedure:
remove the mature entry from
Redelegation.Entriesremove the
Redelegationobject from the store if there are no remaining entries.
Hooks
Other modules may register operations to execute when a certain event has occurred within staking. These events can be registered to execute either right Before or After the staking event (as per the hook name). The following hooks can registered with staking:
AfterValidatorCreated(Context, ValAddress) errorcalled when a validator is created
BeforeValidatorModified(Context, ValAddress) errorcalled when a validator's state is changed
AfterValidatorRemoved(Context, ConsAddress, ValAddress) errorcalled when a validator is deleted
AfterValidatorBonded(Context, ConsAddress, ValAddress) errorcalled when a validator is bonded
AfterValidatorBeginUnbonding(Context, ConsAddress, ValAddress) errorcalled when a validator begins unbonding
BeforeDelegationCreated(Context, AccAddress, ValAddress) errorcalled when a delegation is created
BeforeDelegationSharesModified(Context, AccAddress, ValAddress) errorcalled when a delegation's shares are modified
AfterDelegationModified(Context, AccAddress, ValAddress) errorcalled when a delegation is created or modified
BeforeDelegationRemoved(Context, AccAddress, ValAddress) errorcalled when a delegation is removed
AfterUnbondingInitiated(Context, UnbondingID)called when an unbonding operation (validator unbonding, unbonding delegation, redelegation) was initiated
Events
The staking module emits the following events:
EndBlocker
| Type | Attribute Key | Attribute Value |
|---|---|---|
complete_unbonding | amount | {totalUnbondingAmount} |
complete_unbonding | validator | {validatorAddress} |
complete_unbonding | delegator | {delegatorAddress} |
complete_redelegation | amount | {totalRedelegationAmount} |
complete_redelegation | source_validator | {srcValidatorAddress} |
complete_redelegation | destination_validator | {dstValidatorAddress} |
complete_redelegation | delegator | {delegatorAddress} |
Msg's
MsgCreateValidator
| Type | Attribute Key | Attribute Value |
|---|---|---|
create_validator | validator | {validatorAddress} |
create_validator | amount | {delegationAmount} |
message | module | staking |
message | action | create_validator |
message | sender | {senderAddress} |
MsgEditValidator
| Type | Attribute Key | Attribute Value |
|---|---|---|
edit_validator | commission_rate | {commissionRate} |
edit_validator | min_self_delegation | {minSelfDelegation} |
message | module | staking |
message | action | edit_validator |
message | sender | {senderAddress} |
MsgDelegate
| Type | Attribute Key | Attribute Value |
|---|---|---|
delegate | validator | {validatorAddress} |
delegate | amount | {delegationAmount} |
message | module | staking |
message | action | delegate |
message | sender | {senderAddress} |
MsgUndelegate
| Type | Attribute Key | Attribute Value |
|---|---|---|
unbond | validator | {validatorAddress} |
unbond | amount | {unbondAmount} |
unbond | completion_time [0] | {completionTime} |
message | module | staking |
message | action | begin_unbonding |
message | sender | {senderAddress} |
[0] Time is formatted in the RFC3339 standard
MsgCancelUnbondingDelegation
| Type | Attribute Key | Attribute Value |
|---|---|---|
cancel_unbonding_delegation | validator | {validatorAddress} |
cancel_unbonding_delegation | delegator | {delegatorAddress} |
cancel_unbonding_delegation | amount | {cancelUnbondingDelegationAmount} |
cancel_unbonding_delegation | creation_height | {unbondingCreationHeight} |
message | module | staking |
message | action | cancel_unbond |
message | sender | {senderAddress} |
MsgBeginRedelegate
| Type | Attribute Key | Attribute Value |
|---|---|---|
redelegate | source_validator | {srcValidatorAddress} |
redelegate | destination_validator | {dstValidatorAddress} |
redelegate | amount | {unbondAmount} |
redelegate | completion_time [0] | {completionTime} |
message | module | staking |
message | action | begin_redelegate |
message | sender | {senderAddress} |
[0] Time is formatted in the RFC3339 standard
Parameters
The staking module contains the following parameters:
| Key | Type | Example |
|---|---|---|
UnbondingTime | string (time ns) | "259200000000000" |
MaxValidators | uint16 | 100 |
KeyMaxEntries | uint16 | 7 |
HistoricalEntries | uint16 | 3 |
BondDenom | string | "stake" |
MinCommissionRate | string | "0.000000000000000000" |
Client
CLI
A user can query and interact with the staking module using the CLI.
Query
The query commands allows users to query staking state.
delegation
The delegation command allows users to query delegations for an individual delegator on an individual validator.
Usage:
Example:
Example Output:
delegations
The delegations command allows users to query delegations for an individual delegator on all validators.
Usage:
Example:
Example Output:
delegations-to
The delegations-to command allows users to query delegations on an individual validator.
Usage:
Example:
Example Output:
historical-info
The historical-info command allows users to query historical information at given height.
Usage:
Example:
Example Output:
params
The params command allows users to query values set as staking parameters.
Usage:
Example:
Example Output:
pool
The pool command allows users to query values for amounts stored in the staking pool.
Usage:
Example:
Example Output:
redelegation
The redelegation command allows users to query a redelegation record based on delegator and a source and destination validator address.
Usage:
Example:
Example Output:
redelegations
The redelegations command allows users to query all redelegation records for an individual delegator.
Usage:
Example:
Example Output:
redelegations-from
The redelegations-from command allows users to query delegations that are redelegating from a validator.
Usage:
Example:
Example Output:
unbonding-delegation
The unbonding-delegation command allows users to query unbonding delegations for an individual delegator on an individual validator.
Usage:
Example:
Example Output:
unbonding-delegations
The unbonding-delegations command allows users to query all unbonding-delegations records for one delegator.
Usage:
Example:
Example Output:
unbonding-delegations-from
The unbonding-delegations-from command allows users to query delegations that are unbonding from a validator.
Usage:
Example:
Example Output:
validator
The validator command allows users to query details about an individual validator.
Usage:
Example:
Example Output:
validators
The validators command allows users to query details about all validators on a network.
Usage:
Example:
Example Output:
Transactions
The tx commands allows users to interact with the staking module.
create-validator
The command create-validator allows users to create new validator initialized with a self-delegation to it.
Usage:
Example:
where validator.json contains:
and pubkey can be obtained by using simd tendermint show-validator command.
delegate
The command delegate allows users to delegate liquid tokens to a validator.
Usage:
Example:
edit-validator
The command edit-validator allows users to edit an existing validator account.
Usage:
Example:
redelegate
The command redelegate allows users to redelegate illiquid tokens from one validator to another.
Usage:
Example:
unbond
The command unbond allows users to unbond shares from a validator.
Usage:
Example:
cancel unbond
The command cancel-unbond allow users to cancel the unbonding delegation entry and delegate back to the original validator.
Usage:
Example:
gRPC
A user can query the staking module using gRPC endpoints.
Validators
The Validators endpoint queries all validators that match the given status.
Example:
Example Output:
Validator
The Validator endpoint queries validator information for given validator address.
Example:
Example Output:
ValidatorDelegations
The ValidatorDelegations endpoint queries delegate information for given validator.
Example:
Example Output:
ValidatorUnbondingDelegations
The ValidatorUnbondingDelegations endpoint queries delegate information for given validator.
Example:
Example Output:
Delegation
The Delegation endpoint queries delegate information for given validator delegator pair.
Example:
Example Output:
UnbondingDelegation
The UnbondingDelegation endpoint queries unbonding information for given validator delegator.
Example:
Example Output:
DelegatorDelegations
The DelegatorDelegations endpoint queries all delegations of a given delegator address.
Example:
Example Output:
DelegatorUnbondingDelegations
The DelegatorUnbondingDelegations endpoint queries all unbonding delegations of a given delegator address.
Example:
Example Output:
Redelegations
The Redelegations endpoint queries redelegations of given address.
Example:
Example Output:
DelegatorValidators
The DelegatorValidators endpoint queries all validators information for given delegator.
Example:
Example Output:
DelegatorValidator
The DelegatorValidator endpoint queries validator information for given delegator validator
Example:
Example Output:
HistoricalInfo
Example:
Example Output:
Pool
The Pool endpoint queries the pool information.
Example:
Example Output:
Params
The Params endpoint queries the pool information.
Example:
Example Output:
REST
A user can query the staking module using REST endpoints.
DelegatorDelegations
The DelegtaorDelegations REST endpoint queries all delegations of a given delegator address.
Example:
Example Output:
Redelegations
The Redelegations REST endpoint queries redelegations of given address.
Example:
Example Output:
DelegatorUnbondingDelegations
The DelegatorUnbondingDelegations REST endpoint queries all unbonding delegations of a given delegator address.
Example:
Example Output:
DelegatorValidators
The DelegatorValidators REST endpoint queries all validators information for given delegator address.
Example:
Example Output:
DelegatorValidator
The DelegatorValidator REST endpoint queries validator information for given delegator validator pair.
Example:
Example Output:
HistoricalInfo
The HistoricalInfo REST endpoint queries the historical information for given height.
Example:
Example Output:
Parameters
The Parameters REST endpoint queries the staking parameters.
Example:
Example Output:
Pool
The Pool REST endpoint queries the pool information.
Example:
Example Output:
Validators
The Validators REST endpoint queries all validators that match the given status.
Example:
Example Output:
Validator
The Validator REST endpoint queries validator information for given validator address.
Example:
Example Output:
ValidatorDelegations
The ValidatorDelegations REST endpoint queries delegate information for given validator.
Example:
Example Output:
Delegation
The Delegation REST endpoint queries delegate information for given validator delegator pair.
Example:
Example Output:
UnbondingDelegation
The UnbondingDelegation REST endpoint queries unbonding information for given validator delegator pair.
Example:
Example Output:
ValidatorUnbondingDelegations
The ValidatorUnbondingDelegations REST endpoint queries unbonding delegations of a validator.
Example:
Example Output:
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