M client/req.go → client/req.go

@@ -7,6 +7,7 @@ "fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
+	"strings"
 
 	kzgceremony "github.com/arnaucube/eth-kzg-ceremony-alt"
 )
@@ -155,7 +156,6 @@ return nil, StatusError, err
 	}
 
 	if resp.StatusCode != http.StatusOK {
-		fmt.Println(string(body))
 		switch resp.StatusCode {
 		case http.StatusBadRequest:
 			return nil, StatusWait, fmt.Errorf("call came to early. rate limited")
@@ -166,13 +166,26 @@ return nil, StatusWait, fmt.Errorf("unexpected http code: %d", resp.StatusCode)
 		}
 	}
 
+	// note: a 200 (Ok) code by the Sequencer on try_contribute doesn't
+	// mean that the contributor has been selected. It could mean that the
+	// Sequencer is returning the error AnotherContributionInProgress in a
+	// json msg (see
+	// https://github.com/ethereum/kzg-ceremony-sequencer/blob/2538f2f08d4db880d7f4608e964df0b695bc7d2f/src/api/v1/error_response.rs#L105
+	// )
+
+	// check if body contains the error message of "another contribution in
+	// progress" (despite http statuscode being 200 (Ok))
+	if strings.Contains(string(body), "another contribution in progress") {
+		return nil, StatusWait, fmt.Errorf("another contribution in progress")
+	}
+
 	err = ioutil.WriteFile("prevBatchContribution.json", body, 0600)
 	if err != nil {
 		return nil, StatusError, err
 	}
 	bc := &kzgceremony.BatchContribution{}
 	err = json.Unmarshal(body, bc)
-	return bc, StatusError, err
+	return bc, StatusProceed, err
 }
 
 func (c *Client) PostAbortContribution(sessionID string) ([]byte, error) {

M cmd/cmd.go → cmd/cmd.go

@@ -16,6 +16,7 @@ flag "github.com/spf13/pflag"
 )
 
 var (
+	red    = color.New(color.FgRed)
 	redB   = color.New(color.FgRed, color.Bold)
 	cyan   = color.New(color.FgCyan)
 	cyanB  = color.New(color.FgCyan, color.Bold)
@@ -114,6 +115,7 @@ fmt.Println("starting to compute new contribution")
 	t0 := time.Now()
 	newBatchContribution, err := prevBatchContribution.Contribute([]byte(randomness))
 	if err != nil {
+		fmt.Println("error on prevBatchContribution.Contribute")
 		printErrAndExit(err)
 	}
 	fmt.Println("Contribution computed in", time.Since(t0))
@@ -122,11 +124,13 @@ // store contribution
 	fmt.Println("storing contribution.json")
 	b, err := json.Marshal(newBatchContribution)
 	if err != nil {
-		printErrAndExit(err)
+		// print error but do not exit
+		_, _ = red.Println(err)
 	}
 	err = ioutil.WriteFile("contribution.json", b, 0600)
 	if err != nil {
-		printErrAndExit(err)
+		// print error but do not exit
+		_, _ = red.Println(err)
 	}
 
 	// send contribution
@@ -174,7 +178,6 @@ return authMsg
 }
 
 func printErrAndExit(err error) {
-	red := color.New(color.FgRed)
 	_, _ = red.Println(err)
 	os.Exit(1)
 }

M powersoftau.go → powersoftau.go

@@ -181,7 +181,8 @@ // Contribute takes as input the previous SRS and a random
 // byte slice, and returns the new SRS together with the Proof
 func Contribute(prevSRS *SRS, round int, randomness []byte) (*SRS, *Proof, error) {
 	if len(randomness) < MinRandomnessLen {
-		return nil, nil, fmt.Errorf("err randomness") // WIP
+		return nil, nil, fmt.Errorf("err: randomness length < %d",
+			MinRandomnessLen)
 	}
 	// set tau from randomness
 	tw := tau(round, randomness)