This page introduces the Ethereum adapter suitable for all the Ethereum clients that expose the web3 RPC interface over websockets.

This adapter relies on web3js 1.2.x that is the stable version coming from 1.0.0-beta.37

Hyperledger Besu and Geth are the current tested clients. The tests are driven via standard Ethereum JSON-RPC APIs so other clients should be compatible once docker configurations exist.

Hyperledger Besu does not provide wallet services, so the contractDeployerPassword and fromAddressPassword options are not supported and the private key variants must be used.

Some highlights of the provided features:

  • configurable confirmation blocks threshold

The page covers the following aspects of using the Ethereum adapter:

Assembling the Network Configuration File

The JSON network configuration file of the adapter essentially defines which contract are expected to be on the network and which account the adapter should use to deploy the pointed contracts and which account use to invoke them. Contract necessary for the benchmark are automatically deployed at benchmark startup while the special registry contract needs to be already deployed on the network. ABI and bytecode of the registry contract are reported in the src/contract/ethereum/registry/registry.json.

Connection profile example

We will provide an example of the configuration and then we’ll in deep key by key

    "caliper": {
        "blockchain": "ethereum",
        "command" : {
            "start": "docker-compose -f network/ethereum/1node-clique/docker-compose.yml up -d && sleep 3",
            "end" : "docker-compose -f network/ethereum/1node-clique/docker-compose.yml down"
    "ethereum": {
        "url": "ws://localhost:8545",
        "contractDeployerAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2",
        "contractDeployerAddressPassword": "password",
        "fromAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2",
        "fromAddressPassword": "password",
        "transactionConfirmationBlocks": 12,
        "contracts": {
            "simple": {
                "path": "src/contract/ethereum/simple/simple.json",
                "gas": {
                    "open": 45000,
                    "query": 100000,
                    "transfer": 70000

The top-level caliper attribute specifies the type of the blockchain platform, so Caliper can instantiate the appropriate adapter when it starts. To use this adapter, specify the ethereum value for the blockchain attribute.

Furthermore, it also contains two optional commands: a start command to execute once before the tests and an end command to execute once after the tests. Using these commands is an easy way, for example, to automatically start and stop a test network. When connecting to an already deployed network, you can omit these commands.

These are the keys to provide inside the configuration file under the ethereum one:

The following sections detail each part separately. For a complete example, please refer to the example section or one of the example files in the network/ethereum directories


The URL of the node to connect to. Any host and port can be used if it is reachable. Currently only websocket is supported.

"url": "ws://localhost:8545"

Unfortunately, HTTP connections are explicitly disallowed, as

  1. there is no efficient way to guarantee the order of transactions submitted over http, which leads to nonce errors, and
  2. this adapter relies on web3.js, and this library has deprecated its support for RPC over HTTP.

Deployer address

The address to use to deploy contracts of the network. Without particular or specific needs it can be set to be equal to the benchmark address. Its private key must be hold by the node connected with URL and it must be provided in the checksum form (the one with both lowercase and uppercase letters).

"contractDeployerAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2"

Deployer address private key

The private key for the deployer address. If present then transactions are signed inside caliper and sent “raw” to the ethereum node.

"contractDeployerAddressPrivateKey": "0x45a915e4d060149eb4365960e6a7a45f334393093061116b197e3240065ff2d8"

Deployer address password

The password to use to unlock deployer address. If there isn’t an unlock password, this key must be present as empty string. If the deployer address private key is present this is not used.

"contractDeployerAddressPassword": "gottacatchemall"

Benchmark address

The address to use while invoking all the methods of the benchmark. Its private key must be hold by the node connected with URL and it must be provided in the checksum form (the one with both lowercase and uppercase letters).

"fromAddress": "0xc0A8e4D217eB85b812aeb1226fAb6F588943C2C2"

Benchmark address seed

As an alternative to fromAddress, fromAddressPrivateKey, and fromAddressPassword the network configuration can use a fixed seed and derive needed addresses via BIP-44 key derivation. Each caliper test worker will generate an address for use as fromAddress and fromAddressPrivateKey using the derivation path m/44'/60'/<x>'/0/0, where is the `clientIdx` passed into `getContext`.

This configuration does not override fromAddress, but it takes priority over fromAddressPrivateKey and fromAddressPassword.

"fromAddressSeed": "0x3f841bf589fdf83a521e55d51afddc34fa65351161eead24f064855fc29c9580"

Benchmark address private key

The private key for the benchmark address. If present then transactions are signed inside caliper and sent “raw” to the ethereum node.

This configuration takes priority over fromAddressPassword.

"fromAddressPrivateKey": "0x45a915e4d060149eb4365960e6a7a45f334393093061116b197e3240065ff2d8"

Benchmark address password

The password to use to unlock benchmark address. If there isn’t an unlock password, this key must be present as empty string. If the benchmark address private key is present this is not used.

"fromAddressPassword": "gottacatchemall"

Confirmation blocks

It is the number of blocks the adapter will wait before warn Caliper that a transaction has been successfully executed on the network. You can freely tune it from 1 to the desired confirmations. Keep in mind that in the Ethereum main net (PoW), 12 to 20 confirmations can be required to consider a transaction as accepted in the blockchain. If you’re using different consensus algorith (like clique in the example network provided) it can be safely brought to a lower value. In any case it is up to you.

"transactionConfirmationBlocks": 12

Contract configuration

It is the list, provided as a json object, of contracts to deploy on the network before running the benchmark. You should provide a json entry for each contract; the key will represent the contract identifier to invoke methods on that contract.

For each key you must provide a JSON object with the path field pointing to the contract definition file.

It is also strongly recommended to specify a gas field, which is an object with one field per contract function that you will call in your test. The value of these fields should be set to the amount of gas that will be required to execute your transaction. There is no need for this number to be an exact match, as it’s used to set the gas limit for the transaction, so if your transaction might have a variable gas cost, just set this value to the highest gas usage that you would expect to see for your transaction.

Note: If you do not specify the gas for your contract functions, web3 will automatically call out to your node to estimate the gas requirement before submitting the transaction. This causes three problems. First, it means that your transaction will effectively execute twice, doubling the load on the node serving as your RPC endpoint. Second, the extra call will add significant additional latency to every transaction. Third, your transactions may be reordered, causing transaction failures due to out of order nonces.

"contracts": {
    "simple": {
        "path": "src/contract/ethereum/simple/simple.json",
        "gas": {
            "open": 45000,
            "query": 100000,
            "transfer": 70000
    "second": {
        "path": "src/contract/ethereum/second/second.json",
        "gas": {
            "function": 12345

Contract definition file

Contract definition file is a simple JSON file containing basic information to deploy and use an Ethereum contract. Four keys are required:

Here is an example:

    "name": "The simplest workload contract",
    "abi": [{"constant":true,"inputs":[{"nam......ype":"function"}],
    "bytecode": "0x608060405.........b0029",
    "gas": 259823


It is a name to display in logs when the contract gets deployed. It is only a description name.


It is the ABI generated when compiling the contract. It is required in order to invoke methods on a contract.


It is the bytecode generated when compiling the contract. Note that since it is an hexadecimal it must start with the 0x.


It is the gas required to deploy the contract. It can be easily calculated with widely used solidity development kits or querying to a running Ethereum node.

Using the Adapter Interface

The workload modules interact with the adapter at two phases of the tests: during the initialization of the workload module (the initializeWorkloadModule function), and when submitting invoke or query transactions (the submitTransaction function).

The initializeWorkloadModule function

See the corresponding documentation of the function for the description of its parameters.

The last argument of the function is a sutContext object, which is a platform-specific object provided by the backend blockchain’s connector. The context object provided by this connector is the following:

  fromAddress: "0xA89....7G"
  web3: Web3

The fromAddress property is the benchmark address while web3 is the configured instance of the Web3js client.

The submitTransaction function

The sutAdapter object received (and saved) in the initializeWorkloadModule function is of type ConnectorInterface. Its getType() function returns the fabric string value.

The sendRequests method of the connector API allows the workload module to submit requests to the SUT. It takes a single parameter: an object or array of objects containing the settings of the requests.

The settings object has the following structure:

  • contract: string. Required. The ID of the contract (that is the key specified here).
  • readOnly: boolean. Optional. Indicates whether the request is a TX or a query. Defaults to false.
  • verb: string. Required. The name of the function to call on the contract.
  • value: number. Optional. The value parameter in Wei to be passed to the payable function of the contract.
  • args: mixed[]. Optional. The list of arguments to pass to the method in the correct order as they appear in method signature. It must be an array.
let requestsSettings = [{
    contract: 'simple',
    verb: 'open',
    value: 1000000000000000000000,
    args: ['sfogliatella', 1000]
    contract: 'simple',
    verb: 'open',
    value: 900000000000000000000,
    args: ['baba', 900]

await this.sutAdapter.sendRequests(requestsSettings);

Currently each method call inside sendRequests is sent separately, that is, they are NOT sent as a batch of calls on RPC.

To query a state on a contract state, set the readOnly attribute to true. The difference is that it can’t produce any change on the blockchain and node will answer with its local view of data. Like for traditional requests, currently there is no support for batch queries.

Transaction Data Gathered by the Adapter

The previously discussed invokeSmartContract and queryState functions return an array whose elements correspond to the result of the submitted request(s) with the type of TxStatus. The class provides some standard and platform-specific information about its corresponding transaction.

The standard information provided by the type are the following:

  • GetID():string returns the transaction ID for invokeSmartContract, null for queryState and querySmartContract.
  • GetStatus():string returns the final status of the transaction, either success or failed.
  • GetTimeCreate():number returns the epoch when the transaction was submitted.
  • GetTimeFinal():number return the epoch when the transaction was finished.
  • IsVerified():boolean indicates whether we are sure about the final status of the transaction. Always true for successful transactions. False in all other cases.


The Caliper codebase is released under the Apache 2.0 license. Any documentation developed by the Caliper Project is licensed under the Creative Commons Attribution 4.0 International License. You may obtain a copy of the license, titled CC-BY-4.0, at