package runner import ( "fmt" "log" "net/http" "time" "github.com/cenkalti/backoff/v4" ) // NodeRunner is responsible for starting and managing docker containers to run a node. type NodeRunner interface { StartChains() Chains Shutdown() } // waitForChainStart sets a timeout and repeatedly pings the chains. // If the chain is successfully reached before the timeout, this returns no error. func waitForChainStart(chainDetails ChainDetails) error { // exponential backoff on trying to ping the node, timeout after 30 seconds b := backoff.NewExponentialBackOff() b.MaxInterval = 5 * time.Second b.MaxElapsedTime = 30 * time.Second if err := backoff.Retry(func() error { return pingKava(chainDetails.RpcUrl) }, b); err != nil { return fmt.Errorf("failed connect to chain: %s", err) } b.Reset() // the evm takes a bit longer to start up. wait for it to start as well. if err := backoff.Retry(func() error { return pingEvm(chainDetails.EvmRpcUrl) }, b); err != nil { return fmt.Errorf("failed connect to chain: %s", err) } return nil } func pingKava(rpcUrl string) error { statusUrl := fmt.Sprintf("%s/status", rpcUrl) log.Printf("pinging kava chain: %s\n", statusUrl) res, err := http.Get(statusUrl) if err != nil { return err } defer res.Body.Close() if res.StatusCode >= 400 { return fmt.Errorf("ping to status failed: %d", res.StatusCode) } log.Println("successfully started Kava!") return nil } func pingEvm(evmRpcUrl string) error { log.Println("pinging evm...") res, err := http.Get(evmRpcUrl) if err != nil { return err } defer res.Body.Close() // when running, it should respond 405 to a GET request if res.StatusCode != 405 { return fmt.Errorf("ping to evm failed: %d", res.StatusCode) } log.Println("successfully pinged EVM!") return nil }