libs/os: remove arbitrary os.Exit (#7284)

I think calling os.Exit at arbitrary points is _bad_ and is good to
delete. I think panics in the case of data courruption have a chance
of providing useful information.

internal/consensus/replay_file.go

@@ -18,7 +18,6 @@ import (
 	sm "github.com/tendermint/tendermint/internal/state"
 	"github.com/tendermint/tendermint/internal/store"
 	"github.com/tendermint/tendermint/libs/log"
-	tmos "github.com/tendermint/tendermint/libs/os"
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	"github.com/tendermint/tendermint/types"
 )
@@ -92,7 +91,10 @@ func (cs *State) ReplayFile(file string, console bool) error {
 	var msg *TimedWALMessage
 	for {
 		if nextN == 0 && console {
-			nextN = pb.replayConsoleLoop()
+			nextN, err = pb.replayConsoleLoop()
+			if err != nil {
+				return err
+			}
 		}
 
 		msg, err = pb.dec.Decode()
@@ -194,16 +196,17 @@ func (cs *State) startForReplay() {
 		}()*/
 }
 
-// console function for parsing input and running commands
-func (pb *playback) replayConsoleLoop() int {
+// console function for parsing input and running commands. The integer
+// return value is invalid unless the error is nil.
+func (pb *playback) replayConsoleLoop() (int, error) {
 	for {
 		fmt.Printf("> ")
 		bufReader := bufio.NewReader(os.Stdin)
 		line, more, err := bufReader.ReadLine()
 		if more {
-			tmos.Exit("input is too long")
+			return 0, fmt.Errorf("input is too long")
 		} else if err != nil {
-			tmos.Exit(err.Error())
+			return 0, err
 		}
 
 		tokens := strings.Split(string(line), " ")
@@ -217,13 +220,13 @@ func (pb *playback) replayConsoleLoop() int {
 			// "next N" -> replay next N messages
 
 			if len(tokens) == 1 {
-				return 0
+				return 0, nil
 			}
 			i, err := strconv.Atoi(tokens[1])
 			if err != nil {
 				fmt.Println("next takes an integer argument")
 			} else {
-				return i
+				return i, nil
 			}
 
 		case "back":
@@ -233,7 +236,7 @@ func (pb *playback) replayConsoleLoop() int {
 			// NOTE: "back" is not supported in the state machine design,
 			// so we restart and replay up to
 
-			ctx := context.Background()
+			ctx := context.TODO()
 			// ensure all new step events are regenerated as expected
 
 			newStepSub, err := pb.cs.eventBus.SubscribeWithArgs(ctx, tmpubsub.SubscribeArgs{
@@ -241,7 +244,7 @@ func (pb *playback) replayConsoleLoop() int {
 				Query:    types.EventQueryNewRoundStep,
 			})
 			if err != nil {
-				tmos.Exit(fmt.Sprintf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep))
+				return 0, fmt.Errorf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep)
 			}
 			defer func() {
 				args := tmpubsub.UnsubscribeArgs{Subscriber: subscriber, Query: types.EventQueryNewRoundStep}

internal/state/store.go

@@ -11,7 +11,6 @@ import (
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	tmmath "github.com/tendermint/tendermint/libs/math"
-	tmos "github.com/tendermint/tendermint/libs/os"
 	tmstate "github.com/tendermint/tendermint/proto/tendermint/state"
 	tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
 	"github.com/tendermint/tendermint/types"
@@ -126,8 +125,7 @@ func (store dbStore) loadState(key []byte) (state State, err error) {
 	err = proto.Unmarshal(buf, sp)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		tmos.Exit(fmt.Sprintf(`LoadState: Data has been corrupted or its spec has changed:
-		%v\n`, err))
+		panic(fmt.Sprintf("data has been corrupted or its spec has changed: %+v", err))
 	}
 
 	sm, err := FromProto(sp)
@@ -424,8 +422,7 @@ func (store dbStore) LoadABCIResponses(height int64) (*tmstate.ABCIResponses, er
 	err = abciResponses.Unmarshal(buf)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		tmos.Exit(fmt.Sprintf(`LoadABCIResponses: Data has been corrupted or its spec has
-                changed: %v\n`, err))
+		panic(fmt.Sprintf("data has been corrupted or its spec has changed: %+v", err))
 	}
 	// TODO: ensure that buf is completely read.
 
@@ -544,8 +541,7 @@ func loadValidatorsInfo(db dbm.DB, height int64) (*tmstate.ValidatorsInfo, error
 	err = v.Unmarshal(buf)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		tmos.Exit(fmt.Sprintf(`LoadValidators: Data has been corrupted or its spec has changed:
-                %v\n`, err))
+		panic(fmt.Sprintf("data has been corrupted or its spec has changed: %+v", err))
 	}
 	// TODO: ensure that buf is completely read.
 
@@ -632,8 +628,7 @@ func (store dbStore) loadConsensusParamsInfo(height int64) (*tmstate.ConsensusPa
 	paramsInfo := new(tmstate.ConsensusParamsInfo)
 	if err = paramsInfo.Unmarshal(buf); err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		tmos.Exit(fmt.Sprintf(`LoadConsensusParams: Data has been corrupted or its spec has changed:
-                %v\n`, err))
+		panic(fmt.Sprintf(`data has been corrupted or its spec has changed: %+v`, err))
 	}
 	// TODO: ensure that buf is completely read.
 

libs/os/os.go

@@ -29,11 +29,6 @@ func TrapSignal(logger logger, cb func()) {
 	}()
 }
 
-func Exit(s string) {
-	fmt.Printf(s + "\n")
-	os.Exit(1)
-}
-
 // EnsureDir ensures the given directory exists, creating it if necessary.
 // Errors if the path already exists as a non-directory.
 func EnsureDir(dir string, mode os.FileMode) error {

rpc/jsonrpc/test/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"net/http"
+	"os"
 
 	"github.com/tendermint/tendermint/libs/log"
 	tmos "github.com/tendermint/tendermint/libs/os"
@@ -35,10 +36,12 @@ func main() {
 	config := rpcserver.DefaultConfig()
 	listener, err := rpcserver.Listen("tcp://127.0.0.1:8008", config.MaxOpenConnections)
 	if err != nil {
-		tmos.Exit(err.Error())
+		logger.Error("rpc listening", "err", err)
+		os.Exit(1)
 	}
 
 	if err = rpcserver.Serve(listener, mux, logger, config); err != nil {
-		tmos.Exit(err.Error())
+		logger.Error("rpc serve", "err", err)
+		os.Exit(1)
 	}
 }