smartcontractkit · cl-mayowa · Nov 28, 2025 · Nov 19, 2025 · Nov 19, 2025 · Nov 20, 2025
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+# CRE Indexer Block Trigger Workflows
+
+Workflows for processing new blocks and transactions using block-triggered webhooks (from Alchemy Notify) and matching 
+against watched addresses. These workflows demonstrate the **block trigger pattern** where the workflow reacts to 
+incoming block data and extracts relevant transactions.
+
+## Directory Structure
+
+```
+building-blocks/indexer-block-trigger/
+├── block-trigger-go/     (Go-based workflow)
+│   └── workflow/
+│       ├── main.go
+│       ├── config.staging.json
+│       ├── config.production.json
+│       ├── workflow.yaml
+│       └── README.md
+├── block-trigger-ts/     (TypeScript-based workflow)
+    └── workflow/
+        ├── main.ts
+        ├── package.json
+        ├── config.staging.json (optional)
+        ├── workflow.yaml
+        └── README.md
+
+```
+
+## Overview
+
+These workflows demonstrate how to:
+- React to block events via HTTP webhook triggers 
+(We use Alchemy Notify for this workflow)
+- Match transactions to a list of watched addresses
+- Process and return JSON-formatted block and transaction data
+- Implement the same logic in both Go and TypeScript
+
+Both workflows process incoming block data and extract:
+- Block number, hash, timestamp
+- All transactions in the block
+- Transactions where the `to` address matches a watched address
+
+## Workflows
+
+### 1. block-trigger-go (Go Implementation)
+
+**Language:** Go
+
+**Features:**
+- Uses `http.Trigger` from CRE Go SDK
+- Matches transactions to watched addresses from config
+- Returns formatted JSON summary of block and matched transactions
+
+**Running the workflow:**
+```bash
+cd building-blocks/indexer-block-trigger/block-trigger-go
+cre workflow simulate workflow --non-interactive --trigger-index 0 --http-payload test-block.json --target staging-settings
+```
+
+### 2. block-trigger-ts (TypeScript Implementation)
+
+**Language:** TypeScript
+
+**Features:**
+- Uses HTTP trigger from CRE TypeScript SDK
+- Matches transactions to watched addresses from config
+- Returns formatted JSON summary of block and matched transactions
+
+**Running the workflow:**
+```bash
+cd building-blocks/indexer-block-trigger/block-trigger-ts/workflow
+bun install
+cre workflow simulate workflow --non-interactive --trigger-index 0 --http-payload test-block.json --target staging-settings
+```
+
+## Setup and Testing
+
+### Prerequisites
+
+**For Go workflow:**
+1. Install CRE CLI
+2. Login: `cre login`
+3. Install Go
+
+**For TypeScript workflow:**
+1. Install CRE CLI
+2. Login: `cre login`
+3. Install Bun (or Node.js)
+4. Run `bun install` in the workflow directory
+
+### Running the Workflows
+
+**Go Workflow:**
+```bash
+cd building-blocks/indexer-block-trigger/block-trigger-go
+cre workflow simulate workflow --non-interactive --trigger-index 0 --http-payload test-block.json --target staging-settings
+```
+
+**TypeScript Workflow:**
+```bash
+cd building-blocks/indexer-block-trigger/block-trigger-ts
+cre workflow simulate workflow --non-interactive --trigger-index 0 --http-payload test-block.json --target staging-settings
+```
+
+### Example Output
+
+Both workflows return JSON output like:
+
+```json
+{
+  "blockNumber": 12345678,
+  "blockHash": "0xabc...",
+  "timestamp": 1700000000,
+  "totalLogs": 42,
+  "uniqueTransactions": 10,
+  "matchedTransactions": 2,
+  "transactions": [
+    {
+      "hash": "0xdef...",
+      "from": "0x...",
+      "to": "0x73b668d8374ddb42c9e2f46fd5b754ac215495bc",
+      "value": "1000000000000000000",
+      ...
+    }
+  ]
+}
+```
+
+## Example Use Cases
+
+### 1. Monitoring High-Value Addresses
+Track transactions to specific addresses in real time:
+```json
+{
+  "watchedAddresses": ["0x...", "0x..."]
+}
+```
+
+### 2. Contract Interaction Tracking
+Detect when contracts of interest receive transactions:
+```json
+{
+  "watchedAddresses": ["0xContract1", "0xContract2"]
+}
+```
+
+### 3. Block-Level Analytics
+Summarize block activity and matched transactions for analytics dashboards.
+
+## Reference Documentation
+
+- [CRE Documentation](https://docs.chain.link/cre)
+- [Alchemy Webhooks](https://www.alchemy.com/docs/reference/custom-webhook)
+
@@ -0,0 +1 @@
+*.env
@@ -0,0 +1,19 @@
+module block-trigger-go
+
+go 1.25.3
+
+require (
+	github.com/smartcontractkit/cre-sdk-go v1.0.0
+	github.com/smartcontractkit/cre-sdk-go/capabilities/networking/http v0.10.0
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/shopspring/decimal v1.4.0 // indirect
+	github.com/smartcontractkit/chainlink-protos/cre/go v0.0.0-20250918131840-564fe2776a35 // indirect
+	github.com/stretchr/testify v1.11.1 // indirect
+	google.golang.org/protobuf v1.36.7 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
@@ -0,0 +1,24 @@
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
+github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/shopspring/decimal v1.4.0 h1:bxl37RwXBklmTi0C79JfXCEBD1cqqHt0bbgBAGFp81k=
+github.com/shopspring/decimal v1.4.0/go.mod h1:gawqmDU56v4yIKSwfBSFip1HdCCXN8/+DMd9qYNcwME=
+github.com/smartcontractkit/chainlink-protos/cre/go v0.0.0-20250918131840-564fe2776a35 h1:hhKdzgNZT+TnohlmJODtaxlSk+jyEO79YNe8zLFtp78=
+github.com/smartcontractkit/chainlink-protos/cre/go v0.0.0-20250918131840-564fe2776a35/go.mod h1:jUC52kZzEnWF9tddHh85zolKybmLpbQ1oNA4FjOHt1Q=
+github.com/smartcontractkit/cre-sdk-go v1.0.0 h1:O52/QDmw/W8SJ7HQ9ASlVx7alSMGsewjL0Y8WZmgf5w=
+github.com/smartcontractkit/cre-sdk-go v1.0.0/go.mod h1:CQY8hCISjctPmt8ViDVgFm4vMGLs5fYI198QhkBS++Y=
+github.com/smartcontractkit/cre-sdk-go/capabilities/networking/http v0.10.0 h1:nP6PVWrrTIICvjwQuFitsQecQWbqpPaYzaTEjx92eTQ=
+github.com/smartcontractkit/cre-sdk-go/capabilities/networking/http v0.10.0/go.mod h1:M83m3FsM1uqVu06OO58mKUSZJjjH8OGJsmvFpFlRDxI=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+google.golang.org/protobuf v1.36.7 h1:IgrO7UwFQGJdRNXH/sQux4R1Dj1WAKcLElzeeRaXV2A=
+google.golang.org/protobuf v1.36.7/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
@@ -0,0 +1,27 @@
+# ==========================================================================
+# CRE PROJECT SETTINGS FILE
+# ==========================================================================
+# Project-specific settings for CRE CLI targets.
+# Each target defines cre-cli, account, and rpcs groups.
+#
+# Example custom target:
+# my-target:
+#   account:
+#     workflow-owner-address: "0x123..."            # Optional: Owner wallet/MSIG address (used for --unsigned transactions)
+#   rpcs:
+#     - chain-name: ethereum-mainnet                # Required: Chain RPC endpoints
+#       url: "https://mainnet.infura.io/v3/KEY"
+
+# ==========================================================================
+staging-settings:
+  rpcs:
+    - chain-name: ethereum-testnet-sepolia
+      url: https://ethereum-sepolia-rpc.publicnode.com
+
+# ==========================================================================
+production-settings:
+  rpcs:
+    - chain-name: ethereum-testnet-sepolia
+      url: https://ethereum-sepolia-rpc.publicnode.com
+    - chain-name: ethereum-mainnet
+      url: https://mainnet.infura.io/v3/<YOUR-PROJECT-ID>
@@ -0,0 +1 @@
+secretsNames:
@@ -0,0 +1,22 @@
+# Blank Workflow Example
+
+This template provides a blank workflow example. It aims to give a starting point for writing a workflow from scratch and to get started with local simulation.
+
+Steps to run the example
+
+## 1. Update .env file
+
+You need to add a private key to env file. This is specifically required if you want to simulate chain writes. For that to work the key should be valid and funded.
+If your workflow does not do any chain write then you can just put any dummy key as a private key. e.g.
+```
+CRE_ETH_PRIVATE_KEY=0000000000000000000000000000000000000000000000000000000000000001
+```
+
+## 2. Simulate the workflow
+Run the command from <b>project root directory</b>
+
+```bash
+cre workflow simulate <path-to-workflow> --target=staging-settings
+```
+
+It is recommended to look into other existing examples to see how to write a workflow. You can generate then by running the `cre init` command.
@@ -0,0 +1,6 @@
+{
+  "watchedAddresses": [
+    "0x73b668d8374ddb42c9e2f46fd5b754ac215495bc",
+    "0x6edce65403992e310a62460808c4b910d972f10f"
+  ]
+}
@@ -0,0 +1,6 @@
+{
+  "watchedAddresses": [
+    "0x73b668d8374ddb42c9e2f46fd5b754ac215495bc",
+    "0x6edce65403992e310a62460808c4b910d972f10f"
+  ]
+}