Merge pull request #22 from stealthrocket/trace

replay: support -T,--trace flag like run command

internal/cmd/replay.go

@@ -4,8 +4,10 @@ import (
  "context"
  "errors"
  "fmt"
+ "os"
 
  "github.com/google/uuid"
+ "github.com/stealthrocket/wasi-go"
 
  "github.com/stealthrocket/timecraft/internal/timemachine"
  "github.com/stealthrocket/timecraft/internal/timemachine/wasicall"
@@ -20,15 +22,18 @@ Usage: timecraft replay [options] <process id>
 Options:
  -h, --help Show this usage information
  -r, --registry path Path to the timecraft registry (default to ~/.timecraft)
+ -T, --trace Enable strace-like logging of host function calls
 `
 
 func replay(ctx context.Context, args []string) error {
  var (
  registryPath = "~/.timecraft"
+ trace = false
  )
 
  flagSet := newFlagSet("timecraft replay", replayUsage)
  stringVar(flagSet, &registryPath, "r", "registry")
+ boolVar(flagSet, &trace, "T", "trace")
  flagSet.Parse(args)
 
  args = flagSet.Args()
@@ -89,7 +94,10 @@ func replay(ctx context.Context, args []string) error {
  fallback := wasicall.NewObserver(nil, func(ctx context.Context, s wasicall.Syscall) {
  panic(fmt.Sprintf("system call made after log EOF: %s", s.ID()))
  }, nil)
- system := wasicall.NewFallbackSystem(replay, fallback)
+ var system wasi.System = wasicall.NewFallbackSystem(replay, fallback)
+ if trace {
+ system = &wasi.Tracer{Writer: os.Stderr, System: system}
+ }
 
  // TODO: need to figure this out dynamically:
  hostModule := wasi_snapshot_preview1.NewHostModule(wasi_snapshot_preview1.WasmEdgeV2)