Hydra Processor

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Hydra Processor
Hydra processor is a client-side 'sink' tool used to fetch substrate events from a Hydra indexer. It sequentially applies the event handlers one by one in the order the events have been emitted.
Commands
​hydra-processor help [COMMAND]​
​hydra-processor migrate​
​hydra-processor run​
hydra-processor help [COMMAND]
display help for hydra-processor
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display help for <%= config.bin %>
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​
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USAGE
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  $ hydra-processor help [COMMAND]
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​
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ARGUMENTS
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  COMMAND  command to show help for
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​
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OPTIONS
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  --all  see all commands in CLI
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See code: @oclif/plugin-help​
hydra-processor migrate
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undefined
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​
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USAGE
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  $ hydra-processor migrate
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​
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OPTIONS
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  -e, --env=env  Path to a file with environment variables
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hydra-processor run
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undefined
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​
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USAGE
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  $ hydra-processor run
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​
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OPTIONS
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  -e, --env=env            Path to a file with environment variables
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  -m, --manifest=manifest  Manifest file
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  --id=id                  ID of the processor (useful for multi-processor setups)
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  --indexer=indexer        Indexer URL to source events
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Qickstart
Before the first run, the processor should set up auxiliary database tables required for its work:
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hydra-processor migrate
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Then hydra-processor can be run against the manifest file (by default, it looks up manifest.yml in the current folder)
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hydra-processor run -m <path/to/manifest> -e <path to a file with env variables>
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Environment variables
Hydra processor requires a manifest file and certain environment variables to be set.
Variable
Default
Required
Description
INDEXER_ENDPOINT_URL
-
Yes
Hydra indexer endpoint to source the raw event and extrinsic data
MANIFEST_PATH
manifest.yml
No
Path to the manifest file
DB_NAME
-
Yes
Database name
DB_PORT
-
Yes
Database port
DB_HOST
-
Yes
Database host
DB_USER
-
Yes
Database user
DB_PASS
-
Yes
Database password
PROMETHEUS_PORT
3000
No
A prometheus metrics endpoint is started at this port
POLL_INTERVAL_MS
1 sec (60000 msec)
No
How often the processor polls the indexer for new blocks
The required variables can either be set externally or loaded from a file using the -e flag, e.g.:
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hydra-processor migrate -e .env
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Manifest file
The manifest file describes which and how the events and extrinsics should be processed. Here is an example for Kusama blockchain:
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version: '0.1'
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description: Test manifest
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repository: https://github.com/
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## currently only these settings for the datasouce section are accepted
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dataSource:
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  kind: substrate 
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  chain: kusama
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  indexerVersion: '0.0.4'
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# compiled model classes generated by hydra-cli codegen from the input schema 
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entities:
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  - mappings/lib/generated/**/*.model.js
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mappings:
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  hydraCommonVersion: '0.0.3'
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  # process only blocks with height >= 1M 
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  blockInterval: '[1000000,]'
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  # js module that exports the handler functions 
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  mappingsModule: mappings/lib/mappings
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  # additinal libraries the processor loads
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  # typically it is a module with event and extrinsic types generated by hydra-typegen 
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  imports:
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    - mappings/lib/mappings/generated/types
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  eventHandlers:
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  # event name
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    - event: balances.Transfer 
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  # function handler name with the argument types
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      handler: balancesTransfer(DatabaseManager, Balances.TransferEvent)
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  extrinsicHandlers:
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    # infer defaults here
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    #- extrinsic: Balances.Transfer 
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    #- extrinsic: Sudo.batchCall 
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    #  handler: handleSudoCall(DatabaseManager,SubstrateEvent)
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  preBlockHooks:
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  postBlockHooks:
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Hydra Indexer Gateway
Hydra Typegen
Last modified 4mo ago
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Contents
Commands
hydra-processor help [COMMAND]
hydra-processor migrate
hydra-processor run
Qickstart
Environment variables
Manifest file