Delete Null characters from Logs (#739)

This commit strips null characters from logs, which should fix indexers from crashing.

Closes #735

idb/postgres/internal/encoding/encode.go

@@ -2,6 +2,8 @@ package encoding
 
 import (
 	"encoding/base64"
+	"unicode"
+	"unicode/utf8"
 
 	sdk_types "github.com/algorand/go-algorand-sdk/types"
 	"github.com/algorand/go-codec/codec"
@@ -81,7 +83,33 @@ func convertLocalDeltas(deltas map[uint64]types.StateDelta) map[uint64]types.Sta
 	return res
 }
 
+// printableUTF8OrEmpty checks to see if the entire string is a UTF8 printable string.
+// If this is the case, the string is returned as is. Otherwise, the empty string is returned.
+func printableUTF8OrEmpty(in string) string {
+	// iterate throughout all the characters in the string to see if they are all printable.
+	// when range iterating on go strings, go decode each element as a utf8 rune.
+	for _, c := range in {
+		// is this a printable character, or invalid rune ?
+		if c == utf8.RuneError || !unicode.IsPrint(c) {
+			return ""
+		}
+	}
+	return in
+}
+
+func removeNonUTF8Chars(logs []string) []string {
+	if logs == nil {
+		return nil
+	}
+	res := make([]string, len(logs))
+	for i, log := range logs {
+		res[i] = printableUTF8OrEmpty(log)
+	}
+	return res
+}
+
 func convertEvalDelta(evalDelta types.EvalDelta) types.EvalDelta {
+	evalDelta.Logs = removeNonUTF8Chars(evalDelta.Logs)
 	evalDelta.GlobalDelta = convertStateDelta(evalDelta.GlobalDelta)
 	evalDelta.LocalDeltas = convertLocalDeltas(evalDelta.LocalDeltas)
 	return evalDelta

misc/Dockerfile

@@ -6,7 +6,7 @@ RUN echo "Go image: $GO_IMAGE"
 # Misc dependencies
 ENV HOME /opt    
 ENV DEBIAN_FRONTEND noninteractive    
-RUN apt-get update && apt-get install -y apt-utils curl git git-core bsdmainutils python3 python3-pip make
+RUN apt-get update && apt-get install -y apt-utils curl git git-core bsdmainutils python3 python3-pip make libffi-dev build-essential
 
 # Install algod nightly binaries to the path
 RUN mkdir -p /opt/algorand/{bin,data}