How to use a RPC port during Zombienet tests?

Question

I need a RPC port to deploy Ethereum smart contracts into my parachain's EVM. and the EVM endpoint would look like http://127.0.0.1:xxxx

My current network file:

[relaychain]
default_image = "docker.io/parity/polkadot:{{POLKADOT_VERSION}}"
default_command = "polkadot"
default_args = [ "-lparachain=debug" ]
chain = "rococo-local"

  [[relaychain.nodes]]
  name = "alice"
  validator = true

  [[relaychain.nodes]]
  name = "bob"
  validator = true

[[parachains]]
id = 2000
cumulus_based = true

  [parachains.collator]
  name = "collator01"
  image = "{{COLLATOR_URL}}"
  command = "parachain-collator"
  args = ["-lparachain=debug"]
  
[types.Header]
number = "u64"
parent_hash = "Hash"
post_state = "Hash"

Now when I run Zombienet, I got this from the console log:

parachain-collator --name collator01 --node-key 5e123980fad4770d9ab5b7df7bbee8499943822a8555d11995e8203210065342 --chain /tmp/zombie-7777a966fceaf2c9ff0d46f9a5d9aa5a_-38485-NbMcMKykG6mQ/collator01/cfg/rococo-local-2000.json --base-path /tmp/zombie-7777a966fceaf2c9ff0d46f9a5d9aa5a_-38485-NbMcMKykG6mQ/collator01/data --listen-addr /ip4/0.0.0.0/tcp/33493/ws --rpc-port 42567 --ws-port 32777 --prometheus-external --prometheus-port 38427 --rpc-cors all --unsafe-rpc-external --rpc-methods unsafe --unsafe-ws-external --collator --force-authoring -lparachain=debug -- --chain /tmp/zombie-7777a966fceaf2c9ff0d46f9a5d9aa5a_-38485-NbMcMKykG6mQ/collator01/cfg/rococo-local.json --execution wasm --port 35237 --ws-port 42705 --rpc-port 46031

I see there are two RPC ports: --rpc-port 42567 and --rpc-port 46031

Which one should I use to deploy Ethereum smart contracts into my parachain's EVM ?

How can I get such port number programmatically in my JS script? I guess it is somewhere below?

const { wsUri, userDefinedTypes } = networkInfo.nodesByName[nodeName];
    const api = await zombie.connect(wsUri, userDefinedTypes);
    const validator = await api.query.session.validators();

After printing out the run function arguments of nodeName, networkInfo, args, I got those:

nodeName: alice
networkInfo: {
  tmpDir: '/tmp/zombie-1125ee14af7d14ea72ebc09edb1a453d_-61203-NLdisHdTEY63',
  chainSpecPath: '/tmp/zombie-1125ee14af7d14ea72ebc09edb1a453d_-61203-NLdisHdTEY63/rococo-local.json',
  relay: [
    {
      name: 'alice',
      wsUri: 'ws://127.0.0.1:34997',
      prometheusUri: 'http://127.0.0.1:40159/metrics',
      userDefinedTypes: [Object: null prototype]
    },
    {
      name: 'bob',
      wsUri: 'ws://127.0.0.1:44399',
      prometheusUri: 'http://127.0.0.1:42067/metrics',
      userDefinedTypes: [Object: null prototype]
    }
  ],
  paras: {
    '2000': {
      chainSpecPath: '/tmp/zombie-1125ee14af7d14ea72ebc09edb1a453d_-61203-NLdisHdTEY63/rococo-local-2000.json',
      nodes: [Array]
    }
  },
  nodesByName: {
    alice: {
      name: 'alice',
      wsUri: 'ws://127.0.0.1:34997',
      prometheusUri: 'http://127.0.0.1:40159/metrics',
      userDefinedTypes: [Object: null prototype]
    },
    bob: {
      name: 'bob',
      wsUri: 'ws://127.0.0.1:44399',
      prometheusUri: 'http://127.0.0.1:42067/metrics',
      userDefinedTypes: [Object: null prototype]
    },
    collator01: {
      name: 'collator01',
      wsUri: 'ws://127.0.0.1:42071',
      prometheusUri: 'http://127.0.0.1:41243/metrics',
      userDefinedTypes: [Object: null prototype],
      parachainId: 2000
    }
  }
}
args: []

I could not find the RPC port or URL!

Why are these ports random? Can we predetermine the collator RPC port?

From this https://github.com/paritytech/zombienet/blob/main/docs/src/network-definition-spec.md, it seems I can set the node RPC port, but not collator RPC port!??

Answer 1

There are two nodes inside a collator. One is the relaychain the other is the parachain.

When you type ./collator --rpc-port xxx -- --rpc-port xxx.

The first parameter(the one before the --) apply to the parachain, the second parameter apply to the relaychain.

If you want to interact with your parachain, use the first port.

Answer 2

You need to specify the --rpc-port in your network file in Zombienet tests.

See how I can specify port 6969 to be my collator RPC port:

  [parachains.collator]
  name = "collator01"
  image = "{{COLLATOR_URL}}"
  command = "parachain-collator"
  args = ["-lparachain=debug"]
  rpc_port = 6969