Node Setup and RPC note

Node minimum setup

Here we will be using a local chain-maind folder as the home directory. By default chain data are stored in your home directory ~/.chain-maind. For example, when joining the testnet testnet-croeseid-4:

./chain-maind init mynode --chain-id testnet-croeseid-4 --home ./chain-maind

sed -i.bak -E 's#^(persistent_peers[[:space:]]+=[[:space:]]+).*$#\1"[email protected]:26656,[email protected]:26656"#' ~/.chain-maind/config/config.toml
sed -i.bak -E 's#^(create_empty_blocks_interval[[:space:]]+=[[:space:]]+).*$#\1"5s"#' ~/.chain-maind/config/config.toml
sed -i.bak -E 's#^(timeout_commit[[:space:]]+=[[:space:]]+).*$#\1"2s"#' ~/.chain-maind/config/config.toml  

Enable API and gRPC server

Edit ./chain-main/config/app.toml and update the following section

[api]

# Enable defines if the API server should be enabled.
enable = true

# Swagger defines if swagger documentation should automatically be registered.
swagger = true

# Address defines the API server to listen on.
address = "tcp://0.0.0.0:1317"

...

[grpc]

# Enable defines if the gRPC server should be enabled.
enable = true

# Address defines the gRPC server address to bind to.
address = "0.0.0.0:9090"

Start the node

Afterward, you should be able to start you node by running

./chain-maind start --home ./chain-maind/

where the blockchain data, keys will be stored at the folder <current_path>/chain-maind/

Access RPC server

Tendermint (Local access only)

You can access Tendermint Swagger UI here: https://docs.tendermint.com/master/rpc/#/

Switch the servers to localhost in the dropdown and you can interact with the Swagger UI.

gRPC

There are few clients our team has used before

BloomRPC

• https://github.com/uw-labs/bloomrpc

• GUI client for GRPC services

grpcurl

• https://github.com/fullstorydev/grpcurl

• Like curl, but for gRPC

• Install grpcurl (Mac)

  brew install grpcurl
  

  for other OSs please refer to GitHub

• Query gRPC API

  grpcurl -plaintext localhost:9090 list
  
  cd grpc/proto
  grpcurl -proto ./cosmos/staking/v1beta1/query.proto -plaintext localhost:9090 cosmos.staking.v1beta1.Query.Validators
  

  The reason we have to go to the grpc/proto directory is that gRPC will look for proto files dependency, and they expect that to be under the path you are currently at. To avoid this limitation, we can specify the proto import path.

  grpcurl -import-path ./grpc/proto -proto ./grpc/proto/cosmos/staking/v1beta1/query.proto -plaintext localhost:9090 cosmos.staking.v1beta1.Query.Validators
  

• More query examples

  grpcurl -d ' {"validator_addr": "tcrocncl1l74wnswzx4zsmv674tl99h3h3fgj3al2tdzne7"}' -import-path ./grpc/proto -proto ./grpc/proto/cosmos/staking/v1beta1/query.proto -plaintext localhost:9090 cosmos.staking.v1beta1.Query.Validator
  

Tricks on creating a validator on testnet

1. Make sure your node is fully sync before you join as validator

2. Gas price error

   Sometimes the create-valiator may fail because of the gas. You can use the following command instead (notice we have provide --gas and --gas-price)

   $ ./chain-maind tx staking create-validator \
   --from=[name_of_your_key] \
   --amount=500000tcro \
   --pubkey='{"@type":"/cosmos.crypto.ed25519.PubKey","key":"PUBLIC_KEY"}'  \
   --moniker="[The_id_of_your_node]" \
   --security-contact="[security contact email/contact method]" \
   --chain-id="testnet-croeseid-4" \
   --commission-rate="0.10" \
   --commission-max-rate="0.20" \
   --commission-max-change-rate="0.01" \
   --min-self-delegation="1" \
   --gas="auto" \
   --gas-price="0.1basetcro"