Use terminal colours for direnv output

Error messages are printed red, while expected status messages
(about what is being loaded / exported) are printed in dim black.

cmd_export.go

@@ -58,7 +58,7 @@ var CmdExport = &Cmd{
 			}
 			oldEnv = backupDiff.Reverse().Patch(env)
 			if foundRC == nil {
-				log("unloading")
+				log_status("unloading")
 				newEnv = oldEnv.Copy()
 				delete(newEnv, DIRENV_DIR)
 				delete(newEnv, DIRENV_MTIME)
@@ -111,7 +111,7 @@ var CmdExport = &Cmd{
 			}
 			sort.Strings(out)
 			if len(out) > 0 {
-				log("export %s", strings.Join(out, " "))
+				log_status("export %s", strings.Join(out, " "))
 			}
 		}
 

cmd_stdlib.go

@@ -23,6 +23,20 @@ const STDLIB = `# These are the commands available in an .envrc context
 set -e
 direnv="%s"
 
+# Usage: log_status <command>
+#
+# Logs a status message. Acts like echo,
+# but wraps output in the standard direnv status color
+# and directs it to stderr rather than stdout.
+#
+# Example:
+#
+#    log_status "Loading ..."
+#
+log_status() {
+	echo -e "\e[30m$@\e[0m" >&2
+}
+
 # Usage: has <command>
 #
 # Returns 0 if the <command> is available. Returns 1 otherwise. It can be a
@@ -130,7 +144,7 @@ source_env() {
 		rcfile="$rcfile/.envrc"
 		rcpath="$rcpath/.envrc"
 	fi
-	echo "direnv: loading $rcfile"
+	log_status "direnv: loading $rcfile"
 	pushd "$(dirname "$rcpath")" > /dev/null
 	. "./$(basename "$rcpath")"
 	popd > /dev/null
@@ -304,7 +318,7 @@ layout_go() {
 #
 use() {
 	local cmd="$1"
-	echo "Using $@"
+	log_status "Using $@"
 	shift
 	use_$cmd "$@"
 }

log.go

@@ -5,7 +5,28 @@ import (
 	"os"
 )
 
+const (
+	GreyCode  = "\033[30m"
+	RedCode   = "\033[31m"
+	GreenCode = "\033[32m"
+	CyanCode  = "\033[36m"
+	PlainCode = "\033[0m"
+	ResetCode = "\033[0m"
+)
+
 func log(msg string, a ...interface{}) {
+	log_color(PlainCode, msg, a...)
+}
+
+func log_error(msg string, a ...interface{}) {
+	log_color(RedCode, msg, a...)
+}
+
+func log_status(msg string, a ...interface{}) {
+	log_color(GreyCode, msg, a...)
+}
+
+func log_color(color string, msg string, a ...interface{}) {
 	msg = fmt.Sprintf(msg, a...)
-	fmt.Fprintf(os.Stderr, "direnv: %s\n", msg)
+	fmt.Fprintf(os.Stderr, "%sdirenv: %s%s\n", color, msg, ResetCode)
 }

main.go

@@ -10,7 +10,7 @@ func main() {
 
 	err := CommandsDispatch(env, args)
 	if err != nil {
-		log("error %v", err)
+		log_error("error %v", err)
 		os.Exit(1)
 	}
 }