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75 lines
3.8 KiB
ReStructuredText
75 lines
3.8 KiB
ReStructuredText
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Upgrading CorDapps on a node
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============================
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In order to upgrade a CorDapp on a node to a new version, it needs to be determined whether any backwards compatible
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changes have been made. These could range from database changes, to changes in the protocol.
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For developer information on upgrading CorDapps, see :doc:`upgrading-cordapps`.
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CorDapps must ship with database migration scripts or clear documentation about how to update the database to be compatible with the new version.
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Flow upgrades
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~~~~~~~~~~~~~
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If any backwards-incompatible changes have been made (see :ref:`upgrading-cordapps-backwards-incompatible-flow-changes`
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for more information), the upgrade method detailed below will need to be followed. Otherwise the CorDapp JAR can just
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be replaced with the new version.
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Contract and State upgrades
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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There are two types of contract/state upgrade:
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1. *Implicit:* By allowing multiple implementations of the contract ahead of time, using constraints. See
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:doc:`api-contract-constraints` to learn more.
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2. *Explicit:* By creating a special *contract upgrade transaction* and getting all participants of a state to sign it using the
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contract upgrade flows.
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This documentation only considers the *explicit* type of upgrade, as implicit contract upgrades are handled by the application.
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In an explicit upgrade contracts and states can be changed in arbitrary ways, if and only if all of the state's participants
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agree to the proposed upgrade. The following combinations of upgrades are possible:
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* A contract is upgraded while the state definition remains the same.
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* A state is upgraded while the contract stays the same.
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* The state and the contract are updated simultaneously.
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Running the upgrade
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~~~~~~~~~~~~~~~~~~~
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If a contract or state requires an explicit upgrade then all states will need updating to the new contract at a time agreed
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by all participants. The updated CorDapp JAR needs to be distributed to all relevant parties in advance of the changeover
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time.
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In order to perform the upgrade, follow the following steps:
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* If required, do a flow drain to avoid the definition of states or contracts changing whilst a flow is in progress (see :ref:`upgrading-cordapps-flow-drains` for more information)
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* By RPC using the ``setFlowsDrainingModeEnabled`` method with the parameter ``true``
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* Via the shell by issuing the following command ``run setFlowsDrainingModeEnabled enabled: true``
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* Check that all the flows have completed
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* By RPC using the ``stateMachinesSnapshot`` method and checking that there are no results
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* Via the shell by issuing the following command ``run stateMachinesSnapshot``
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* Once all flows have completed, stop the node
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* Replace the existing JAR with the new one
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* Make any database changes required to any custom vault tables for the upgraded CorDapp,
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following the database upgrade steps in :doc:`node-operations-cordapp-deployment`.
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The database update for a CorDapp upgrade follows the same steps as database setup for a new CorDapp.
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* Restart the node
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* If you drained the node prior to upgrading, switch off flow draining mode to allow the node to continue to receive requests
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* By RPC using the ``setFlowsDrainingModeEnabled`` method with the parameter ``false``
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* Via the shell by issuing the following command ``run setFlowsDrainingModeEnabled enabled: false``
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* Run the contract upgrade authorisation flow (``ContractUpgradeFlow$Initiate``) for each state that requires updating on every node.
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* You can do this manually via RPC but for anything more than a couple of states it is assumed that a script will be
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provided by the CorDapp developer to query the vault and run this for all states
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* The contract upgrade initiate flow only needs to be run on one of the participants for each state. The flow will
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automatically upgrade the state on all participants.
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