PRE Application Events

When there is an interaction with PRE Application smart contracts, various on-chain events are emitted. These events are defined in the Contracts API, and they are queryable via the nucypher status events CLI command, and allows for any PRE Application event to be queried.

Querying Events

Since the number of events returned may be large, by default the query is limited to events within block numbers for the current period. However, this is configurable using the --from-block option.


Depending on the Ethereum provider being used, the number of results a query is allowed to return may be limited. For example, on Infura this limit is currently 10,000.

For a full list of CLI options, run:

$ nucypher status events --help

Event Filters

To aid with query limits and more specific queries, events can be filtered using the --event-filter option. Multiple --event-filter options can be defined, but note that only properties classified as indexed in the event’s solidity definition can be used as a filter.

The event filter can be defined as follows, --event-filter <PARAMETER_NAME>=<FILTER_VALUE>.

Legacy Events

To query for events related to the NuCypher Network prior to the merge to Threshold Network, e.g. CommitmentMade or Minted, use the --legacy flag.

For example, to view all of the legacy NuCypher Network commitments ever made by the node associated with a specific Staker run:

$ nucypher status events --legacy --eth-provider <ETH PROVIDER URI> --contract-name StakingEscrow --event-name CommitmentMade --event-filter staker=<STAKING_ADDRESS> --from-block 0

Reading Latest Chaindata...
Retrieving events from block 0 to latest

--------- StakingEscrow Events ---------

  - (EventRecord) staker: <STAKER_ADDRESS>, period: 18551, value: 1234567890123456789012, block_number: 11057641
  - (EventRecord) staker: <STAKER_ADDRESS>, period: 18552, value: 1234567890123456789012, block_number: 11063640
  - (EventRecord) staker: <STAKER_ADDRESS>, period: 18553, value: 1234567890123456789012, block_number: 11070103
  - (EventRecord) staker: <STAKER_ADDRESS>, period: 18554, value: 1234567890123456789012, block_number: 11076964

CSV Output

CLI output can be cumbersome when trying to generate insights and correlate different events. Instead, the event data can be written to a CSV file using either of the following command-line options:

  • --csv - flag to write event information to default CSV files in the current directory with default filenames

  • --csv-file <FILEPATH> - write event information to a specific CSV file at the provided filepath


If there were no events found, a CSV file is not written to.


When using the --csv-file option, since different events can have different properties, the --event-name and --contract-name options must be specified. If querying for multiple events at the same time i.e. running the command without --event-name, the --csv option should be used to generate separate default filenames for the different events.