feat: feegrant module for blobs submission via DA Light node

.vitepress/config.ts

@@ -508,6 +508,10 @@ function sidebarHome() {
           text: "Transaction resubmission guidelines",
           link: "/developers/transaction-resubmission",
         },
+        {
+          text: "FeeGrant module for blobs submission",
+          link: "/developers/feegrant-for-blobs",
+        },
         {
           text: "Node API",
           link: "/developers/node-api",

developers/feegrant-for-blobs.md

@@ -0,0 +1,141 @@
+# FeeGrant module for blobs submission
+
+## Overview
+
+This guide provides developers with the knowledge to use the FeeGrant
+module on the Celestia's Mocha testnet chain for granting a data
+availability node's account to submit blobs without constantly
+funding it, enabling a third-party account to cover the transaction fees.
+
+## Pre-requisites
+
+- celestia-app CLI installed
+- celestia-node and CLI tools installed
+- Access to a Mocha node (e.g., `https://rpc.celestia-mocha.com:443`)
+- Running DA Light node on Mocha testnet
+- Separate Celestia account with sufficient funds
+
+## Introduction
+
+Each DA node contains a Celestia account that is used to pay for blobs
+submissions. To unify the fee payment process, the FeeGrant module
+allows a third-party account to pay for the fees incurred by the DA node's
+account. You will need one account that will contain the funds and another
+account that will be in the DA node. You will see the DA node's account
+once you initialize the node.
+
+## Granting fee allowances
+
+To grant fee allowances, allowing a third-party (granter) account to pay
+for the fees incurred by a Celestia data availability node (grantee)
+account, use the following command:
+
+```bash
+celestia-appd tx feegrant grant \
+  [grantee_address] [granter_address] \
+  --home [path_to_grantee] \
+  --node [rpc_endpoint] \
+  --spend-limit 1000000utia \
+  --allowed-messages "/cosmos.bank.v1beta1.MsgSend,/celestia.blob.v1.MsgPayForBlobs" \
+  --chain-id mocha-4 \
+  --keyring-backend test \
+  --fees 20000utia \
+  --broadcast-mode block \
+  --yes
+```
+
+Example:
+[FeeGrant transaction on Mocha](https://mocha.celenium.io/tx/802a17777fbeab416f6fa2c25f0c56dd9cc8a92afc2a96293d114ac7c22efb5c)
+
+## Verifying balances and transactions
+
+Before diving into the specifics of verifying balances and transactions,
+it's important to note that currently, it's necessary to fund the light node
+in order for its transactions to be included in the state of the chain. We recognize
+this step as an extra layer of complexity and are actively working on improving
+the user experience. Future updates to the nodes implementations will aim to
+make this step non-mandatory for the FeeGrant module to function effectively,
+streamlining the process for developers and users alike.
+
+### Check balance of the new DA light node
+
+To check the balance of a new light node, use the following command:
+<!-- markdownlint-disable MD013 -->
+```bash
+celestia state balance --node.store ~/.celestia-light-mocha-4/
+```
+<!-- markdownlint-enable MD013 -->
+
+Example response when the account balance does not exist:
+
+```json
+{
+  "result": {
+    "denom": "utia",
+    "amount": "0"
+  }
+}
+```
+
+This indicates that the light node currently does not have any funds.
+
+### Funding the light node
+
+As of now, to ensure the light node's transactions are included in the
+state, you must initially fund the light node with the least amount
+of funds using the following command:
+
+```bash
+celestia-appd tx bank send [granter_address] [grantee_address] 10000utia \
+  --node https://rpc.celestia-mocha.com:443 \
+  --chain-id mocha-4 \
+  --keyring-backend test \
+  --fees 20000utia \
+  --broadcast-mode block \
+  --yes \
+  --home ~/.celestia-app/
+```
+
+### Submitting a blob
+
+To submit a blob, utilize the following command:
+<!-- markdownlint-disable MD013 -->
+```bash
+celestia blob submit 0x6B656B 'nice' --node.store $NODE_STORE
+```
+<!-- markdownlint-enable MD013 -->
+
+### Checking account balances after submission
+
+Light node account:
+After submitting a blob, you can check the light node account's balance
+to verify that the fees have been deducted:
+<!-- markdownlint-disable MD013 -->
+```bash
+celestia state balance --node.store ~/.celestia-light-mocha-4/
+```
+<!-- markdownlint-enable MD013 -->
+
+Example output showing fees are not deducted:
+
+```json
+{
+  "result": {
+    "denom": "utia",
+    "amount": "10000"
+  }
+}
+```
+
+### Third-party account:
+
+To confirm that the fees have been deducted from the third-party account that
+granted the fee allowance, run:
+
+```bash
+celestia-appd query bank balances [granter_address] \
+--node https://rpc.celestia-mocha.com:443 --denom utia
+```
+
+This output will show the remaining balance after fees have been deducted,
+confirming that the FeeGrant module is working as intended.