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Initiators

Cron

The Cron initiator is a simple way to schedule recurring job runs, using standard cron syntax.

Cron Parameters

Cron takes one parameter, schedule which is a cron like schedule string. The Cron‘s schedule is follows standard cron syntax but prepends an timezone to be specified with CRON_TZ, with an optional field for seconds. For example: CRON_TZ=UTC */10 * * * * would run every 10 minutes with the timezone set to UTC. CRON_TZ=UTC */30 * * * * * would run every 30 seconds.

Example

"initiators": [
    {
        "type": "cron",
        "params": {
            "schedule": "CRON_TZ=UTC */10 * * *"
        }
    }
]

EthLog

The EthLog initiator creates an Ethereum log filter, and when any log comes in it is passed on as the input to the a new job run.

EthLog Parameters

EthLog takes the same parameters as an Ethereum log filter.

Example

"initiators": [
    {
        "type": "ethlog",
        "address": "0xCAFE000000000000000000000000000000000001"
    }
]

External

The external initiator works like the web initiator, but is given its own credentials along with a name and URL.

You can create an external initiator by running the chainlink initiators create NAME URL command. This will give you an access key and secret pair, which will be used for incoming requests to invoke a job with this external initiator, and an outgoing token and secret pair which optionally can be used to help the Chainlink node authenticate with external services. Any incoming requests must provide the access key and secret in order to invoke the job run.

External Parameters

external requires a name to be set to handle authentication in order to invoke the job run.

Example

"initiators": [
    {
        "type": "external",
        "params": {
            "name": "myexternalservice"
        }
    }
]

RunAt

The RunAt initiator triggers a one off job run at the time specified.

RunAt Parameters

RunAt takes one parameter, time. time accepts a ISO8601 string or a Unix timestamp.

Example

"initiators": [
    {
        "type": "runat",
        "params": {
            "time": "2019-09-20T12:20:00.000Z"
        }
    }
]

RunLog

The RunLog initiator is the easiest initiator to use when integrating Chainlink with on-chain contracts. It works similarly to EthLog, but adds some helpful glue in to stitch together the off-chain job with the on-chain contracts.

When a RunLog job is created, Chainlink begins watching the blockchain for any log events that include that job’s ID. If any of the events that come back match the log event signature of the Chainlink oracle contract, then the Chainlink node parses the data out of that log and passes it into a new log run.

A new run created by a RunLog is automatically given the parameters needed for an EthTx task to report the run back to the contract that originally created the event log.

RunLog Parameters

RunLog initiators take an optional address parameter and requesters parameter. The address parameter is a single Ethereum address and the requesters parameter is an array of Ethereum addresses. By adding the address parameter, you make the event filter of the RunLog initiator more restrictive, only listening for events from that address, instead of any address. By adding the requesters parameter, you only allow requests to come from an address within the array.

Example

"initiators": [
    {
        "type": "runlog",
        "params": {
            "address": "0xCAFE000000000000000000000000000000000001",
            "requesters": [
                "0xCAFE000000000000000000000000000000000002",
                "0xCAFE000000000000000000000000000000000003"
            ]
        }
    }
]

Web

The Web initiator enables jobs to be triggered via web requests, specifically POSTs to /v2/specs/:jobID/runs. Requests coming in to create new job runs must be authenticated by cookie.

NOTE: For convenience, there is a "Run" button in the operator web UI for the job which will trigger a job run.

Web Parameters

Web currently takes no parameters.

Example

"initiators": [
    {
        "type": "web"
    }
]

Updated 18 days ago

Initiators


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