Configurable terminal colors

Signed-off-by: Sean P. Kane <spkane00@gmail.com>

README.md

@@ -1,6 +1,6 @@
 [![asciicinema example](https://asciinema.org/a/gPEIEo1NzmDTUu2bEPsUboqmU.png)](https://asciinema.org/a/gPEIEo1NzmDTUu2bEPsUboqmU)
 
-# BuildKit
+# BuildKit <!-- omit in toc -->
 
 [![GoDoc](https://godoc.org/github.com/moby/buildkit?status.svg)](https://godoc.org/github.com/moby/buildkit/client/llb)
 [![Build Status](https://github.com/moby/buildkit/workflows/build/badge.svg)](https://github.com/moby/buildkit/actions?query=workflow%3Abuild)
@@ -45,11 +45,11 @@ Join `#buildkit` channel on [Docker Community Slack](http://dockr.ly/slack)
 
 - [Used by](#used-by)
 - [Quick start](#quick-start)
-  - [Starting the `buildkitd` daemon:](#starting-the-buildkitd-daemon)
+  - [Starting the `buildkitd` daemon](#starting-the-buildkitd-daemon)
   - [Exploring LLB](#exploring-llb)
   - [Exploring Dockerfiles](#exploring-dockerfiles)
     - [Building a Dockerfile with `buildctl`](#building-a-dockerfile-with-buildctl)
-    - [Building a Dockerfile using external frontend:](#building-a-dockerfile-using-external-frontend)
+    - [Building a Dockerfile using external frontend](#building-a-dockerfile-using-external-frontend)
   - [Output](#output)
     - [Image/Registry](#imageregistry)
     - [Local directory](#local-directory)
@@ -76,6 +76,8 @@ Join `#buildkit` channel on [Docker Community Slack](http://dockr.ly/slack)
 - [Opentracing support](#opentracing-support)
 - [Running BuildKit without root privileges](#running-buildkit-without-root-privileges)
 - [Building multi-platform images](#building-multi-platform-images)
+  - [Configuring `buildctl`](#configuring-buildctl)
+    - [Color Output Controls](#color-output-controls)
 - [Contributing](#contributing)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
@@ -121,7 +123,7 @@ $ brew install buildkit
 
 To build BuildKit from source, see [`.github/CONTRIBUTING.md`](./.github/CONTRIBUTING.md).
 
-### Starting the `buildkitd` daemon:
+### Starting the `buildkitd` daemon
 
 You need to run `buildkitd` as the root user on the host.
 
@@ -193,7 +195,7 @@ buildctl build \
 
 `--local` exposes local source files from client to the builder. `context` and `dockerfile` are the names Dockerfile frontend looks for build context and Dockerfile location.
 
-#### Building a Dockerfile using external frontend:
+#### Building a Dockerfile using external frontend
 
 External versions of the Dockerfile frontend are pushed to https://hub.docker.com/r/docker/dockerfile-upstream and https://hub.docker.com/r/docker/dockerfile and can be used with the gateway frontend. The source for the external frontend is currently located in `./frontend/dockerfile/cmd/dockerfile-frontend` but will move out of this repository in the future ([#163](https://github.com/moby/buildkit/issues/163)). For automatic build from master branch of this repository `docker/dockerfile-upstream:master` or `docker/dockerfile-upstream:master-labs` image can be used.
 
@@ -669,6 +671,16 @@ Please refer to [`docs/rootless.md`](docs/rootless.md).
 
 Please refer to [`docs/multi-platform.md`](docs/multi-platform.md).
 
+### Configuring `buildctl`
+
+#### Color Output Controls
+
+`buildctl` has support for modifying the colors that are used to output information to the terminal. You can set the environment variable `BUILDKIT_COLORS` to something like `run=blue;cancel=yellow;warn=orange;error=123,12,0` to set the colors that you would like to use. Setting `NO_COLOR` to anything will disable any colorized output as recommended by [no-color.org](https://no-color.org/).
+
+Parsing errors will be reported but ignored. This will result in default color values being used where needed.
+
+- [The list of pre-defined colors](https://github.com/moby/buildkit/blob/master/util/progress/progressui/colors.go).
+
 ## Contributing
 
 Want to contribute to BuildKit? Awesome! You can find information about contributing to this project in the [CONTRIBUTING.md](/.github/CONTRIBUTING.md)

util/progress/progressui/colors.go

@@ -0,0 +1,135 @@
+package progressui
+
+import (
+	"encoding/csv"
+	"errors"
+	"strconv"
+	"strings"
+
+	"github.com/morikuni/aec"
+	"github.com/sirupsen/logrus"
+)
+
+var termColorMap = map[string]aec.ANSI{
+	"default": aec.DefaultF,
+
+	"black":   aec.BlackF,
+	"blue":    aec.BlueF,
+	"cyan":    aec.CyanF,
+	"green":   aec.GreenF,
+	"magenta": aec.MagentaF,
+	"red":     aec.RedF,
+	"white":   aec.WhiteF,
+	"yellow":  aec.YellowF,
+
+	"light-black":   aec.LightBlackF,
+	"light-blue":    aec.LightBlueF,
+	"light-cyan":    aec.LightCyanF,
+	"light-green":   aec.LightGreenF,
+	"light-magenta": aec.LightMagentaF,
+	"light-red":     aec.LightRedF,
+	"light-white":   aec.LightWhiteF,
+	"light-yellow":  aec.LightYellowF,
+}
+
+func setUserDefinedTermColors(colorsEnv string) {
+	fields := readBuildkitColorsEnv(colorsEnv)
+	if fields == nil {
+		return
+	}
+	for _, field := range fields {
+		parts := strings.SplitN(field, "=", 2)
+		if len(parts) != 2 || strings.Contains(parts[1], "=") {
+			err := errors.New("A valid entry must have exactly two fields")
+			logrus.WithError(err).Warnf("Could not parse BUILDKIT_COLORS component: %s", field)
+			continue
+		}
+		k := strings.ToLower(parts[0])
+		v := parts[1]
+		if c, ok := termColorMap[strings.ToLower(v)]; ok {
+			parseKeys(k, c)
+		} else if strings.Contains(v, ",") {
+			if c := readRGB(v); c != nil {
+				parseKeys(k, c)
+			}
+		} else {
+			err := errors.New("Colors must be a name from the pre-defined list or a valid 3-part RGB value")
+			logrus.WithError(err).Warnf("Unknown color value found in BUILDKIT_COLORS: %s=%s", k, v)
+		}
+	}
+}
+
+func readBuildkitColorsEnv(colorsEnv string) []string {
+	csvReader := csv.NewReader(strings.NewReader(colorsEnv))
+	csvReader.Comma = ':'
+	fields, err := csvReader.Read()
+	if err != nil {
+		logrus.WithError(err).Warnf("Could not parse BUILDKIT_COLORS. Falling back to defaults.")
+		return nil
+	}
+	return fields
+}
+
+func readRGB(v string) aec.ANSI {
+	csvReader := csv.NewReader(strings.NewReader(v))
+	fields, err := csvReader.Read()
+	if err != nil {
+		logrus.WithError(err).Warnf("Could not parse value %s as valid comma-separated RGB color. Ignoring.", v)
+		return nil
+	}
+	if len(fields) != 3 {
+		err = errors.New("A valid RGB color must have three fields")
+		logrus.WithError(err).Warnf("Could not parse value %s as valid RGB color. Ignoring.", v)
+		return nil
+	}
+	ok := isValidRGB(fields)
+	if ok {
+		p1, _ := strconv.Atoi(fields[0])
+		p2, _ := strconv.Atoi(fields[1])
+		p3, _ := strconv.Atoi(fields[2])
+		c := aec.Color8BitF(aec.NewRGB8Bit(uint8(p1), uint8(p2), uint8(p3)))
+		return c
+	}
+	return nil
+}
+
+func parseKeys(k string, c aec.ANSI) {
+	key := strings.ToLower(k)
+	switch key {
+	case "run":
+		colorRun = c
+	case "cancel":
+		colorCancel = c
+	case "error":
+		colorError = c
+	case "warning":
+		colorWarning = c
+	default:
+		logrus.Warnf("Unknown key found in BUILDKIT_COLORS (expected: run, cancel, error, or warning): %s", k)
+	}
+}
+
+func isValidRGB(s []string) bool {
+	for _, n := range s {
+		num, err := strconv.Atoi(n)
+		if err != nil {
+			logrus.Warnf("A field in BUILDKIT_COLORS appears to contain an RGB value that is not an integer: %s", strings.Join(s, ","))
+			return false
+		}
+		ok := isValidRGBValue(num)
+		if ok {
+			continue
+		} else {
+			logrus.Warnf("A field in BUILDKIT_COLORS appears to contain an RGB value that is not within the valid range of 0-255: %s", strings.Join(s, ","))
+			return false
+		}
+	}
+	return true
+}
+
+func isValidRGBValue(i int) bool {
+	if (i >= 0) && (i <= 255) {
+		return true
+	}
+	return false
+}

util/progress/progressui/display.go

@@ -108,6 +108,7 @@ type job struct {
 	name        string
 	status      string
 	hasError    bool
+	hasWarning  bool
 	isCanceled  bool
 	vertex      *vertex
 	showTerm    bool
@@ -829,8 +830,12 @@ func (disp *display) print(d displayInfo, width, height int, all bool) {
 				color = colorCancel
 			} else if j.hasError {
 				color = colorError
+			} else if j.hasWarning {
+				color = colorWarning
+			}
+			if color != nil {
+				out = aec.Apply(out, color)
 			}
-			out = aec.Apply(out, color)
 		}
 		fmt.Fprint(disp.c, out)
 		lineCount++

util/progress/progressui/init.go

@@ -0,0 +1,37 @@
+package progressui
+
+import (
+	"os"
+	"runtime"
+
+	"github.com/morikuni/aec"
+)
+
+var colorRun aec.ANSI
+var colorCancel aec.ANSI
+var colorWarning aec.ANSI
+var colorError aec.ANSI
+
+func init() {
+	// As recommended on https://no-color.org/
+	if _, ok := os.LookupEnv("NO_COLOR"); ok {
+		// nil values will result in no ANSI color codes being emitted.
+		return
+	} else if runtime.GOOS == "windows" {
+		colorRun = termColorMap["cyan"]
+		colorCancel = termColorMap["yellow"]
+		colorWarning = termColorMap["yellow"]
+		colorError = termColorMap["red"]
+	} else {
+		colorRun = termColorMap["blue"]
+		colorCancel = termColorMap["yellow"]
+		colorWarning = termColorMap["yellow"]
+		colorError = termColorMap["red"]
+	}
+
+	// Loosely based on the standard set by Linux LS_COLORS.
+	if _, ok := os.LookupEnv("BUILDKIT_COLORS"); ok {
+		envColorString := os.Getenv("BUILDKIT_COLORS")
+		setUserDefinedTermColors(envColorString)
+	}
+}

util/progress/progressui/term.go

@@ -1,12 +0,0 @@
-//go:build !windows
-// +build !windows
-
-package progressui
-
-import "github.com/morikuni/aec"
-
-var (
-	colorRun    = aec.BlueF
-	colorCancel = aec.YellowF
-	colorError  = aec.RedF
-)

util/progress/progressui/term_windows.go

@@ -1,12 +0,0 @@
-//go:build windows
-// +build windows
-
-package progressui
-
-import "github.com/morikuni/aec"
-
-var (
-	colorRun    = aec.CyanF
-	colorCancel = aec.YellowF
-	colorError  = aec.RedF
-)