How to Schedule Price Updates with Gelato
This guide explains how to create an automated Gelato task that updates Pyth price feeds on a schedule. The task will update the on-chain price after either a fixed time interval or if the price has changed by a certain percentage.
Introduction to Gelato
Gelato (opens in a new tab) is web3’s decentralized backend empowering developers to create augmented smart contracts that are automated, gasless and off-chain aware on all major EVM-compatible blockchains. Gelato offers Web3 Functions (W3F) that connect your smart contracts to off-chain data and computation by running decentralized cloud functions
Gelato W3F Pyth Task
The Gelato W3F Pyth Task is a Gelato task that updates Pyth price feeds on a schedule. The task is deployed to IPFS and can be used by anyone to schedule price updates for any Pyth price feed. The task is configured via a yaml file that is hosted on GitHub gist which contains various parameters such as the price feeds to update, the update frequency, price deviation threshold. Once the task is deployed, these configuration parameters can be updated by editing the GitHub gist and without needing to redeploy the task.
Steps
1. Join Gelato Web3 Functions whitelist
Web3 Functions are currently in private beta. In order to use them, you must be added to the whitelist. Apply to the whitelist by reaching out to the Gelato team here (opens in a new tab).
2. Configure your task
The Gelato task reads a yaml configuration file from a GitHub gist.
Create a GitHub gist by logging into GitHub and navigating to here (opens in a new tab). Add a file called config.yaml
.
Copy the example gist (opens in a new tab) and edit the parameters for
the environment you're deploying to and configure your price feeds and update thresholds. See
directory (opens in a new tab) for
some example configuration files. These parameters can be updated at any time by editing the gist even if the task has
already been deployed. The task will automatically pick up these configuration changes and use them for subsequent executions.
3. Create the task
Use the link below to auto-populate the task parameters with the Pyth web3 function code:
The pyth web3 function code is deployed to IPFS, so you can use it via the cid/link above. You can find a copy of the web3 function code here (opens in a new tab)
Choose network, and then in the "Task secrets" section, set GIST_ID
to the gistId of the gist you created in step 2.
Note that the beta currently only supports triggering the task every minute. Once other time intervals are available, you will need to ensure that your current subscription plan with Gelato supports the desired number of monthly runs. See Subscription Plans (opens in a new tab).
4. Fund the task
There are two sets of fees that must be paid before the task can execute successfully
Gelato Fees
Gelato's fees are paid through 1Balance (opens in a new tab). Once you are whitelisted, visit the 1Balance app (opens in a new tab) and deposit USDC on Polygon to top up your Gelato balance which will be used to pay the Gelato fees on all supported chains. These include computational costs and transaction gas fees. Testnet executions are subsidized by Gelato and free. Make sure to create your 1Balance account using the same wallet address that you used to create the Gelato task.
Switch network to Polygon
Deposit USDC
Pyth Fees
Updating a pyth price feed requires the caller to pay a small fee. Pyth fees are paid in the native token of the chain
where the task is running. The method that updates the price is payable and the update transaction has to include the
corresponding fee in the msg.value
.
The on-chain transaction executed via a web3 function gets routed through a proxy smart contract
which is solely owned by the web3 function task creator. This proxy smart contract is known as the dedicatedMsgSender
and will be deployed the first time a task is created for a given wallet address.
Pyth fees are paid by the dedicatedMsgSender
and transaction fees as well as computational costs by 1Balance.
You will need to transfer over the native tokens to dedicatedMsgSender
on every chain where you want to run
the task using a standard transfer. The dedicatedMsgSender
address can be found in the Gelato task details
under Target smart contract
as the Your msg.sender
field
You can simply open your wallet and send native tokens to dedicatedMsgSender
on the chain(s) where you want to run the
task.
5. Check task execution
Once your task has been successfully created, you can check the task execution details in the Gelato app. Example Pyth Web3 Function on Mumbai (opens in a new tab)
Managing your Gelato Task
Monitoring
To ensure that your tasks are running as expected, you can set up monitoring. Gelato supports monitoring 1Balance and
address balances as well as execution statuses for tasks. You can set up monitoring for your Gelato balance and
the dedicatedMsgSender
address on each chain where you are running tasks and receive notifications in either
Telegram or Discord.
See the following links for more information:
Updating configuration
To update the configuration of your task, such as adding/removing new price feeds or changing the deviation thresholds,
you can simply update the config.yaml
file in your gist. The task will automatically pick up the changes and use them.
Note that the config.yaml
includes a configRefreshRateInSeconds
parameter which determines how often the task will
fetch the latest configuration from the gist vs reading a locally cached version. This is to prevent the task from being
rate-limited by GitHub. To verify that your most recent task execution used the latest configuration, you can check the
"Storage" tab on the task details page and look at the configuration stored under the pythConfig
key.
Notes
If you want to customize the behavior of the web3 function beyond what is supported by updating the config.yaml, you can clone this repo (opens in a new tab) and deploy your own version of the web3 function. You can then use the cid of your deployed web3 function to create a new task. See README.md (opens in a new tab) and Gelato Web3 Function Documentation (opens in a new tab) for more details.