Explorer and Indexer

The next step is to be able to see what is actually happening in your blockchain. One easy way to do this is to use Blockscout (opens in a new tab).

Before You Begin

You'll need to create a separate archive node and install a Docker Engine to work with Blockscout.

Archive mode

Blockscout expects to interact with an Ethereum execution client in archive mode (opens in a new tab). If your op-geth is running in full mode, you can create a separate archive node. To do so, follow the directions to add a node, but in the command you use to start op-geth replace:

	--gcmode=full \

with

	--gcmode=archive \

Docker

The easiest way to run Blockscout is to use Docker. Download and install Docker engine (opens in a new tab).

Installation and Configuration

Clone the Blockscout repository.

cd ~
git clone https://github.com/blockscout/blockscout.git
cd blockscout/docker-compose

Depending on the version of Docker you have, there may be an issue with the environment path. Run this command to fix it:
```
ln -s `pwd`/envs ..
```
If op-geth in archive mode runs on a different computer or a port that isn't 8545, edit docker-compose-no-build-geth.yml to set ETHEREUM_JSONRPC_HTTP_URL to the correct URL.

Start Blockscout

docker compose -f docker-compose-no-build-geth.yml up

Usage

After the docker containers start, browse to http:// < computer running Blockscout > :4000 to view the user interface.

You can also use the API (opens in a new tab)

GraphQL

Blockscout's API includes GraphQL (opens in a new tab) support under /graphiql. For example, this query looks at addresses.

query {
  addresses(hashes:[
   "0xcB69A90Aa5311e0e9141a66212489bAfb48b9340", 
   "0xC2dfA7205088179A8644b9fDCecD6d9bED854Cfe"])

GraphQL queries start with a top level entity (or entities). In this case, our top level query (opens in a new tab) is for multiple addresses.

Note that you can only query on fields that are indexed. For example, here we query on the addresses. However, we couldn't query on contractCode or fetchedCoinBalance.

 {
    hash
    contractCode
    fetchedCoinBalance

The fields above are fetched from the address table.

    transactions(first:5) {

We can also fetch the transactions that include the address (either as source or destination). The API does not let us fetch an unlimited number of transactions, so here we ask for the first 5.

      edges {
        node {

Because this is a graph (opens in a new tab), the entities that connect two types, for example addresses and transactions, are called edges. At the other end of each edge there is a transaction, which is a separate node.

          hash
          fromAddressHash
          toAddressHash
          input
        }

These are the fields we read for each transaction.

      }
    }
  }
}

Finally, close all the brackets.

Settlement Hacks Chain Troubleshooting