stdenv: refactor nix logging functions (#370742)

pkgs/stdenv/generic/setup.sh

@@ -56,60 +56,102 @@ getAllOutputNames() {
     fi
 }
 
+# All provided arguments are joined with a space, then prefixed by the name of the function which invoked `nixLog` (or
+# the hook name if the caller was an implicit hook), then directed to $NIX_LOG_FD, if it's set.
+nixLog() {
+  # Return a value explicitly instead of the implicit return of the last command (result of the test).
+  # NOTE: By requiring NIX_LOG_FD be set, we avoid dumping logging inside of nix-shell.
+  [[ -z ${NIX_LOG_FD-} ]] && return 0
+
+  # Use the function name of the caller, unless it is _callImplicitHook, in which case use the name of the hook.
+  local callerName="${FUNCNAME[1]}"
+  if [[ $callerName == "_callImplicitHook" ]]; then
+    callerName="${hookName:?}"
+  fi
+  printf "%s: %s\n" "$callerName" "$*" >&"$NIX_LOG_FD"
+}
+
+# Identical to nixLog, but additionally prefixed by the logLevel.
+# NOTE: This function is only every meant to be called from the nix*Log family of functions.
+_nixLogWithLevel() {
+  # Return a value explicitly instead of the implicit return of the last command (result of the test).
+  # NOTE: By requiring NIX_LOG_FD be set, we avoid dumping logging inside of nix-shell.
+  [[ -z ${NIX_LOG_FD-} || ${NIX_DEBUG:-0} -lt ${1:?} ]] && return 0
+
+  local logLevel
+  case "${1:?}" in
+  0) logLevel=ERROR ;;
+  1) logLevel=WARN ;;
+  2) logLevel=NOTICE ;;
+  3) logLevel=INFO ;;
+  4) logLevel=TALKATIVE ;;
+  5) logLevel=CHATTY ;;
+  6) logLevel=DEBUG ;;
+  7) logLevel=VOMIT ;;
+  *)
+    echo "_nixLogWithLevel: called with invalid log level: ${1:?}" >&"$NIX_LOG_FD"
+    return 1
+    ;;
+  esac
+
+  # Use the function name of the caller, unless it is _callImplicitHook, in which case use the name of the hook.
+  # NOTE: Our index into FUNCNAME is 2, not 1, because we are only ever to be called from the nix*Log family of
+  # functions, never directly.
+  local callerName="${FUNCNAME[2]}"
+  if [[ $callerName == "_callImplicitHook" ]]; then
+    callerName="${hookName:?}"
+  fi
+
+  # Use the function name of the caller's caller, since we should only every be invoked by nix*Log functions.
+  printf "%s: %s: %s\n" "$logLevel" "$callerName" "${2:?}" >&"$NIX_LOG_FD"
+}
+
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlError` in the Nix source.
 nixErrorLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 0 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 0 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlWarn` in the Nix source.
 nixWarnLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 1 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 1 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlNotice` in the Nix source.
 nixNoticeLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 2 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 2 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlInfo` in the Nix source.
 nixInfoLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 3 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 3 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlTalkative` in the Nix source.
 nixTalkativeLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 4 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 4 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlChatty` in the Nix source.
 nixChattyLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 5 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 5 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlDebug` in the Nix source.
 nixDebugLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 6 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 6 "$*"
 }
 
 # All provided arguments are joined with a space then directed to $NIX_LOG_FD, if it's set.
 # Corresponds to `Verbosity::lvlVomit` in the Nix source.
 nixVomitLog() {
-    if [[ -z ${NIX_LOG_FD-} ]] || [[ ${NIX_DEBUG:-0} -lt 7 ]]; then return; fi
-    printf "%s\n" "$*" >&"$NIX_LOG_FD"
+  _nixLogWithLevel 7 "$*"
 }
 
 # Log a hook, to be run before the hook is actually called.