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Run an EVM Tracing Node

Overview​

Running a tracing node on an Astar chain allows you to debug EVM transactions and have enhanced access to transaction pool using EVM debug RPC.

Requirements​

Requirements for running a tracing node are similar to what we recommend for an archive node. Read more about this here.

Node launch​

Tracing node setup in general is similar to the Archive Node setup, except for some additional launch flags.

note

There's no need for special client to run EVM tracing since the release of v5.44.0

important

EVM RPC calls are disabled by default, and require the --enable-evm-rpc flag to be enabled. Please refer to this page for more info.

Runtime overriding​

Tracing runtimes has additional debug API that makes possible deep (and slow) transaction debugging. For this reason it's not part of production runtimes. So, for using tracing features, runtime must be overrided by special tracing runtime.

For example, if current rutime is astar-52 then astar-runtime-52-substitute-tracing.wasm blob should be used for overriding and debug recent transactions. Tracing runtime is published in release assets as evm-tracing-artifacts, please check latest release here.

For runtime override please create folder somewhere node can access it, by default it could be /var/lib/astar/wasm. And then copy overriding runtimes into this folder. This folder is cumulative, this means you can place all previous runtimes at the same place to be able to trace historical data.

mkdir /var/lib/astar/wasm
cp astar-runtime-52-substitute-tracing.wasm /var/lib/astar/wasm
chown -hR astar /var/lib/astar/wasm

When wasm blob located correctly the node launch string should be addicted by --wasm-runtime-overrides=/var/lib/astar/wasm flag. Then service should be restarted, if all go well then node will catch up tracing runtime and substitute on-chain version by it.

important

Tracing data at a certain block requires to override the runtime version of this block. To use tracing on an ancient blocks, you need to add the runtime that was in place at this block.

All Astar previous runtime overrides (prior to release on Github) can be downloaded here. They are necessary if you want to trace transactions on ancient blocks

Service parameters​

The service file for a tracing node will look like this

tip

Please make sure to change {NODE_NAME}

[Unit]
Description=Astar EVM tracing node

[Service]
User=astar
Group=astar
  
ExecStart=/usr/local/bin/astar-collator \
  --chain astar \
  --state-pruning archive \
  --blocks-pruning archive \
  --rpc-cors all \
  --name {NODE_NAME} \
  --base-path /var/lib/astar \
  --rpc-methods Safe \
  --rpc-max-request-size 10 \
  --rpc-max-response-size 50 \
  --enable-evm-rpc \
  --ethapi=txpool,debug,trace \
  --wasm-runtime-overrides /var/lib/astar/wasm \
  --telemetry-url 'wss://telemetry.polkadot.io/submit/ 0' \
  -- \
  --sync warp

Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target