PlantUML diagrams (#8712)

* Overview of keepers in object capability model (OCM)

* Updates to the spec, making clarifications

* Create a sequence diagram of a (fresh) delegation

* Misc notes, not yet decided where to put them

* Description of the shares abstraction in validators

* Model all keeper dependencies and move the UML file to docs

* Move and rename delegation sequence diagram

* Move shares description

* Remove TODO

* Diagram touch-ups

* Add how consensus power is calculated

* remove temp file

* Diagram improvements

* Describe slashing in more detail

* Describe redelegation

* Describe unbonding

* Delegation updates

* Delegation updates

* Make a diagram describing overall transaction flow

* Add delegation flows for the events of tokens being bonded/unbonding/etc.

* Grammar fix

* Diagram updates: distinguish alts, remove numbering.

* Use groups instead of "func:" participants

* Remove unused keepers from dependency diagram

* Add title to unbonding diagram

* Move keeper dependencies

* small doc updates

* remove numbers on sequence diagram

* !!!WIP EndBlock

* Explain "Last"-prefix in storage

* Remove `panic` step (they are supposed to never happen)

* EndBlock sequence diagram (with TODOs)

* Add TODO

* More visible TODOs

* Remove numbering

* Complete EndBlock

* Remove numbering

* Remove TODOs and update title

* add title back

* remove endblock seq-diagram

* Make power index update conditional on not being jailed

* update title

* Move files to /docs

* Install PlantUML and compile images to png and txt

* Use transaction flow in documentation

* Use staking UML in staking docs

* Clarify uml with inline doc

* Add keeper deps diagram to docs

* Only produce SVG images

Co-authored-by: hjort <>
Co-authored-by: Marko <[email protected]>

Dockerfile

@@ -13,7 +13,7 @@
 FROM golang:alpine AS build-env
 
 # Install minimum necessary dependencies,
-ENV PACKAGES curl make git libc-dev bash gcc linux-headers eudev-dev python3
+ENV PACKAGES curl make git libc-dev bash gcc linux-headers eudev-dev python3 plantuml
 RUN apk add --no-cache $PACKAGES
 
 # Set working directory for the build

docs/building-modules/msg-services.md

@@ -54,6 +54,10 @@ This method takes care of marshaling the `res` parameter to protobuf and attachi
 
 +++ https://github.com/cosmos/cosmos-sdk/blob/d55c1a26657a0af937fa2273b38dcfa1bb3cff9f/proto/cosmos/base/abci/v1beta1/abci.proto#L81-L95
 
+This diagram shows a typical structure of an `Msg` Service, and how the message propagates through the module.
+
+![](../uml/transaction_flow.svg)
+
 ## Legacy Amino `Msg`s
 
 ### `handler` type

docs/core/ocap.md

@@ -70,6 +70,10 @@ gaia app.
 
 +++ https://github.com/cosmos/cosmos-sdk/blob/v0.41.4/simapp/app.go#L249-L273
 
+The following diagram shows the current dependencies between keepers.
+
+![](../uml/keeper_dependencies.svg)
+
 ## Next {hide}
 
 Learn about the [`runTx` middleware](./runtx_middleware.md) {hide}

docs/pre.sh

@@ -9,4 +9,6 @@ for D in ../x/*; do
   fi
 done
 
-cat ../x/README.md | sed 's/\.\/x/\/modules/g' | sed 's/spec\/README.md//g' | sed 's/\.\.\/docs\/building-modules\/README\.md/\/building-modules\/intro\.html/g' > ./modules/README.md
+cat ../x/README.md | sed 's/\.\/x/\/modules/g' | sed 's/spec\/README.md//g' | sed 's/\.\.\/docs\/building-modules\/README\.md/\/building-modules\/intro\.html/g' > ./modules/README.md
+
+plantuml -tsvg uml/*.puml

docs/uml/begin_redelegation_sequence.puml

@@ -0,0 +1,50 @@
+@startuml
+'https://plantuml.com/sequence-diagram
+
+title: Redelegation
+
+msgServer -> keeper : BeginRedelegation(delAddr, valSrcAddr, valDstAddr, sharesAmount)
+participant  "keeper (staking)" as keeper
+keeper -> keeper : get number of sharew
+note left: If the delegator has more shares than the total shares in the validator\n(due to rounding errors), then just withdraw the max number of shares.
+keeper -> keeper : check the redelegation uses correct denom
+
+alt valSrcAddr == valDstAddr
+  keeper --> msgServer : error
+end
+alt transitive redelegation
+  keeper --> msgServer : error
+end
+alt already has max redelegations
+  keeper --> msgServer : error
+  note left : this is the number of redelegations for a specific (del, valSrc, valDst) triple\ndefault : 7
+end
+
+
+keeper -> keeper : Unbond(del, valSrc) returns returnAmount
+...
+note left : See unbonding diagram
+
+alt returnAmount is zero
+keeper -> msgServer : error
+end
+
+keeper -> keeper : Delegate(del, returnAmount, status := valSrc.status, valDst, subtractAccount := false)
+note left : See delegation diagram
+...
+
+alt validator is unbonded
+    keeper -> msgServer : current time
+end
+
+alt unbonding not complete, or just started
+    database store
+    keeper -> store : create redelegation object
+    keeper -> store : insert redelegation in queue, to be processed at the appropriate time
+end
+
+msgServer <-- keeper : completion time of the redelegation
+msgServer -> msgServer : emit event: delegator, valSrc, valSrc,\nsharesAmount, completionTime
+
+@enduml
+

docs/uml/delegation_sequence.puml

@@ -0,0 +1,93 @@
+@startuml
+'https://plantuml.com/sequence-diagram
+
+title: Delegating (currently undelegated funds delegator)
+
+participant "msgServer (staking)"
+participant  "keeper (staking)" as keeper
+participant validator
+participant keeper.bankKeeper
+participant vestingAccount
+participant ctx.EventManager
+
+database store
+
+"msgServer (staking)" -> keeper : Delegate(Context, DelegatorAddress, Amount, Validator, tokenSrc := Unbonded)
+
+alt exchange rate is invalid (tokens in validator is 0)
+    keeper -->  "msgServer (staking)" : error
+end
+
+alt perform a new delegation
+    keeper -> keeper : delegation := create delegation object
+    keeper -> keeper : BeforeDelegationCreated hook
+    note left: Calls IncrementValidatorPeriod (Used to calculate distribution) in keeper/validator.go
+else delegation exists, more tokens being added
+    keeper -> keeper : BeforeDelegationModified hook
+    note left: withdraw current delegation rewards (and increment period)
+end
+
+alt delegating from an account (subtractTokens == true)
+    keeper -> keeper.bankKeeper : DelegateCoinsFromAccountToModule
+    group DelegateCoinsFromAccountToModule function
+        keeper.bankKeeper -> keeper.bankKeeper : DelegateCoinsFromAccountToModule
+        keeper.bankKeeper -> keeper.bankKeeper : DelegateCoins
+        group DelegateCoins function
+            keeper.bankKeeper --> keeper.bankKeeper : Check the delegator has enough balances of all tokens delegated
+            keeper.bankKeeper --> keeper.bankKeeper : Track delegation (register that it exists to keep track of it)
+            alt validator is currently bonded
+                keeper.bankKeeper --> store : Transfer tokens from delegator to BondedTokensPool.
+            else validator is currently unbonded or unbonding
+                keeper.bankKeeper --> store : Transfer tokens from delegator to NotBondedTokensPool.
+            end
+            group trackDelegation function
+                keeper.bankKeeper -> keeper.bankKeeper : trackDelegation
+                alt delegator is a vesting account
+                    keeper.bankKeeper -> vestingAccount : keep track of this delegation
+                end
+            end
+        end
+    end
+    keeper <-- keeper.bankKeeper : nil (success)
+else moving tokens between pools (subtractTokens == false)
+    alt delegator tokens are not bonded but validator is bonded
+       keeper -> keeper.bankKeeper : SendCoinsFromModuleToModule(notBondedPool, bondedPool, coins)
+    else delegator tokens are bonded but validator is not bonded
+       keeper -> keeper.bankKeeper : SendCoinsFromModuleToModule(bondedPool, notBondedPool, coins)
+    end
+    group SendCoins function
+        keeper.bankKeeper -> keeper.bankKeeper : SendCoins
+        keeper.bankKeeper -> ctx.EventManager : Emit TransferEvent(to, from, amount)
+        alt amount of spendable (balance - locked) coins too low
+            keeper <-- keeper.bankKeeper : error
+        end
+        keeper.bankKeeper -> store : subtract balance from sender
+        keeper.bankKeeper -> store : add balance to recipient
+    end
+end
+
+keeper -> validator : AddTokensFromDel
+validator -> validator : calculate number of shares to issue
+note left: If there are no shares (validator being created) then 1 token = 1 share.\nIf there are already shares, then\nadded shares =  (added tokens amount) * (current validator shares) / (current validator tokens)
+
+validator -> validator : add delegated tokens to validator
+keeper <-- validator : validator, addedShares
+keeper -> store : update validator state
+keeper -> keeper: calculate new validator's power
+note left : Number of tokens divided by PowerReduction (default: 1,000,000,000,000,000,000 = 10^18)
+alt validator is not jailed
+    keeper -> store : update validator's power in power index
+    note left : the power index has entries shaped as 35 || power || address.\nThis makes the validators sorted by power, high to low.
+end
+
+keeper -> keeper : AfterDelegationModified hook
+note left: Calls initializeDelegation\nStore the previous period\nCalculate the number of tokens from shares\n(shares the delegator has) * (tokens in delegation object)/(total tokens delegated to the validator)\nStore delegation starting info.
+"msgServer (staking)" <-- keeper : newShares (ignored by Delegate function)
+
+
+"msgServer (staking)" -> "msgServer (staking)" : Emit event: Delegation(ValidatorAddress)
+"msgServer (staking)" -> "msgServer (staking)" : Emit event: Message(DelegatorAddress)
+"msgServer (staking)" -> "msgServer (staking)" : telemetry(Amount, Denom)
+
+@enduml
+

docs/uml/keeper_dependencies.puml

@@ -0,0 +1,36 @@
+@startuml
+'https://plantuml.com/class-diagram
+
+title: The dependencies between Keepers (Feb 2021)
+
+abstract class Staking
+abstract class Distribution
+abstract class Slashing
+abstract class Evidence
+abstract class Bank
+abstract class "Auth/Account" as Auth
+abstract class Gov
+abstract class Mint
+
+Staking <|-- Mint
+Bank <|-- Mint
+
+Staking <|-- Gov
+Bank <|-- Gov
+Auth <|-- Gov
+
+Auth <|-- Bank
+
+Bank <|-- Distribution
+Auth <|-- Distribution
+Staking <|-- Distribution
+
+Staking <|-- Evidence
+Slashing <|-- Evidence
+
+Staking <|-- Slashing
+
+Auth <|-- Staking
+Bank <|-- Staking
+
+@enduml

docs/uml/transaction_flow.puml

@@ -0,0 +1,22 @@
+What happens after a transaction is unmarshalled and is processed by the SDK?
+
+@startuml
+'https://plantuml.com/sequence-diagram
+
+actor User
+User -> baseApp : Transaction Type<Tx>
+baseApp -> router : Route(ctx, msgRoute)
+router --> baseApp : handler
+baseApp -> handler: Msg<Tx>(Context, Msg(...))
+handler -> msgServer : <Tx>(Context, Msg)
+alt addresses invalid, denominations wrong, etc.
+msgServer --> handler : error
+end
+msgServer -> keeper : perform action, update context
+keeper --> msgServer : results, error code
+msgServer -> Context.EventManager : Emit relevant events
+msgServer -> msgServer : maybe wrap results in more structure
+msgServer --> handler : result, error code
+baseApp <-- handler : results, error code
+
+@enduml

docs/uml/unbond_sequence.puml

@@ -0,0 +1,51 @@
+@startuml
+'https://plantuml.com/sequence-diagram
+
+title: Undelegate
+
+msgServer -> keeper : Undelegate(delAddr, valAddr, tokenAmount)
+
+keeper -> keeper : calculate number of shares the tokenAmount represents
+
+alt wrong denom
+    msgServer <-- keeper : error
+end
+
+group Unbond(delAddr, valAddr, shares)
+    keeper -> keeper: BeforeDelegationSharesModified hook
+    alt no such delegation
+        keeper --> msgServer : error
+    end
+    alt not enough shares
+        keeper --> msgServer : error
+    end
+    alt delegator is the operator of the validator\nand validator is not already jailed\nand unbonding would put self-delegation under min threshold
+                keeper -> keeper : jail the validator, but proceed with unbonding
+                note left : Default min delegation threshold : 1 share
+    end
+
+    database store
+
+    alt complete unbonding, all shares removed
+        keeper -> store : remove delegation object
+    else there are still shares delegated (not a complete undbonding)
+        keeper -> store : update delegation object
+        keeper -> keeper : AfterDelegationModified hook
+    end
+
+    keeper -> store : update validator power index
+    keeper -> store : update validator information (including token amount)
+
+    alt validator status is "unbonded" and it has no more tokens
+       keeper -> store : delete the validator
+       note right : otherwise, do this in EndBlock once validator is unbonded
+    end
+end
+
+alt validator is bonded
+    keeper -> bankKeeper : send tokens from bonded pool to not bonded pool
+end
+
+msgServer -> msgServer : emit event : EventTypeUnbond(delAddr, valAddr, tokenAmount, completion time)
+
+@enduml

x/staking/spec/03_messages.md

@@ -80,6 +80,8 @@ 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.
 
+![](docs/uml/delegation_sequence.svg)
+
 ## Msg/Undelegate
 
 The `Msg/Undelegate` service message allows delegators to undelegate their tokens from
@@ -112,6 +114,8 @@ When this service message is processed the following actions occur:
 - if there are no more `Shares` in the delegation, then the delegation object is removed from the store
   - under this situation if the delegation is the validator's self-delegation then also jail the validator.
 
+![](docs/uml/unbond_sequence.svg)
+
 ## Msg/BeginRedelegate
 
 The redelegation command allows delegators to instantly switch validators. Once
@@ -146,3 +150,5 @@ When this service message is processed the following actions occur:
 - Delegate the token worth to the destination validator, possibly moving tokens back to the bonded state.
 - if there are no more `Shares` in the source delegation, then the source delegation object is removed from the store
   - under this situation if the delegation is the validator's self-delegation then also jail the validator.
+
+![](docs/uml/begin_redelegation_sequence.svg)