cmd/geth, internal/flags: print envvar config source and bad names (#…

…28119)

cmd/geth/main.go

@@ -249,7 +249,11 @@ func init() {
  app.Before = func(ctx *cli.Context) error {
  maxprocs.Set() // Automatically set GOMAXPROCS to match Linux container CPU quota.
  flags.MigrateGlobalFlags(ctx)
- return debug.Setup(ctx)
+ if err := debug.Setup(ctx); err != nil {
+ return err
+ }
+ flags.CheckEnvVars(ctx, app.Flags, "GETH")
+ return nil
  }
  app.After = func(ctx *cli.Context) error {
  debug.Exit()

internal/flags/helpers.go

@@ -20,9 +20,11 @@ import (
  "fmt"
  "os"
  "regexp"
+ "sort"
  "strings"
 
  "github.com/ethereum/go-ethereum/internal/version"
+ "github.com/ethereum/go-ethereum/log"
  "github.com/ethereum/go-ethereum/params"
  "github.com/mattn/go-isatty"
  "github.com/urfave/cli/v2"
@@ -263,3 +265,37 @@ func AutoEnvVars(flags []cli.Flag, prefix string) {
  }
  }
 }
+
+// CheckEnvVars iterates over all the environment variables and checks if any of
+// them look like a CLI flag but is not consumed. This can be used to detect old
+// or mistyped names.
+func CheckEnvVars(ctx *cli.Context, flags []cli.Flag, prefix string) {
+ known := make(map[string]string)
+ for _, flag := range flags {
+ docflag, ok := flag.(cli.DocGenerationFlag)
+ if !ok {
+ continue
+ }
+ for _, envvar := range docflag.GetEnvVars() {
+ known[envvar] = flag.Names()[0]
+ }
+ }
+ keyvals := os.Environ()
+ sort.Strings(keyvals)
+
+ for _, keyval := range keyvals {
+ key := strings.Split(keyval, "=")[0]
+ if !strings.HasPrefix(key, prefix) {
+ continue
+ }
+ if flag, ok := known[key]; ok {
+ if ctx.Count(flag) > 0 {
+ log.Info("Config environment variable found", "envvar", key, "shadowedby", "--"+flag)
+ } else {
+ log.Info("Config environment variable found", "envvar", key)
+ }
+ } else {
+ log.Warn("Unknown config environment variable", "envvar", key)
+ }
+ }
+}