Add promptutil to shared/promptuil (#6757)

* Add promptutil to shared/promptutil
* fixes
* comment

go.sum

@@ -383,6 +383,7 @@ github.com/ianlancetaylor/cgosymbolizer v0.0.0-20200424224625-be1b05b0b279 h1:Ip
 github.com/ianlancetaylor/cgosymbolizer v0.0.0-20200424224625-be1b05b0b279/go.mod h1:a5aratAVTWyz+nJMmDsN8O4XTfaLfdAsB1ysCmZX5Bw=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/imdario/mergo v0.3.5/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
+github.com/inconshreveable/log15 v0.0.0-20170622235902-74a0988b5f80 h1:g/SJtZVYc1cxSB8lgrgqeOlIdi4MhqNNHYRAC8y+g4c=
 github.com/inconshreveable/log15 v0.0.0-20170622235902-74a0988b5f80/go.mod h1:cOaXtrgN4ScfRrD9Bre7U1thNq5RtJ8ZoP4iXVGRj6o=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/influxdata/flux v0.65.0/go.mod h1:BwN2XG2lMszOoquQaFdPET8FRQfrXiZsWmcMO9rkaVY=

shared/promptutil/BUILD.bazel

@@ -0,0 +1,16 @@
+load("@prysm//tools/go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "prompt.go",
+        "validate.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/shared/promptutil",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@com_github_logrusorgru_aurora//:go_default_library",
+        "@com_github_nbutton23_zxcvbn_go//:go_default_library",
+        "@org_golang_x_crypto//ssh/terminal:go_default_library",
+    ],
+)

shared/promptutil/prompt.go

@@ -0,0 +1,90 @@
+package promptutil
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/logrusorgru/aurora"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+var au = aurora.NewAurora(true)
+
+// ValidatePrompt requests the user for text and expects it to fulfil la provided validation function.
+func ValidatePrompt(promptText string, validateFunc func(string) error) (string, error) {
+	var responseValid bool
+	var response string
+	for !responseValid {
+		fmt.Printf("%s:\n", au.Bold(promptText))
+		_, err := fmt.Scanln(&response)
+		if err != nil && !strings.Contains(err.Error(), "unexpected newline") {
+			return "", err
+		}
+		response = strings.TrimRight(response, "\r\n")
+		if err := validateFunc(response); err != nil {
+			fmt.Printf("Entry not valid: %s\n", au.BrightRed(err))
+		} else {
+			responseValid = true
+		}
+	}
+	return response, nil
+}
+
+// DefaultPrompt prompts the user for any text and performs no validation. If nothing is entered it returns the default.
+func DefaultPrompt(promptText string, defaultValue string) (string, error) {
+	var response string
+	fmt.Printf("%s %s:\n", promptText, fmt.Sprintf("(%s: %s)", au.BrightGreen("default"), defaultValue))
+	_, err := fmt.Scanln(&response)
+	if err != nil && !strings.Contains(err.Error(), "unexpected newline") {
+		return "", err
+	}
+	response = strings.TrimRight(response, "\r\n")
+	if response == "" {
+		return defaultValue, nil
+	}
+	return response, nil
+}
+
+// DefaultAndValidatePrompt prompts the user for any text and expects it to fulfill a validation function. If nothing is entered
+// the default value is returned.
+func DefaultAndValidatePrompt(promptText string, defaultValue string, validateFunc func(string) error) (string, error) {
+	var responseValid bool
+	var response string
+	for !responseValid {
+		fmt.Printf("%s %s:\n", promptText, fmt.Sprintf("(%s: %s)", au.BrightGreen("default"), defaultValue))
+		_, err := fmt.Scanln(&response)
+		if err != nil && !strings.Contains(err.Error(), "unexpected newline") {
+			return "", err
+		}
+		response = strings.TrimRight(response, "\r\n")
+		if response == "" {
+			return defaultValue, nil
+		}
+		if err := validateFunc(response); err != nil {
+			fmt.Printf("Entry not valid: %s\n", au.BrightRed(err))
+		}
+	}
+	return response, nil
+}
+
+// PasswordPrompt prompts the user for a password, that repeatedly requests the password until it qualifies the
+// passed in validation function.
+func PasswordPrompt(promptText string, validateFunc func(string) error) (string, error) {
+	var responseValid bool
+	var response string
+	for !responseValid {
+		fmt.Printf("%s:\n", au.Bold(promptText))
+		bytePassword, err := terminal.ReadPassword(int(os.Stdin.Fd()))
+		if err != nil {
+			return "", err
+		}
+		response = strings.TrimRight(string(bytePassword), "\r\n")
+		if err := validateFunc(response); err != nil {
+			fmt.Printf("\nEntry not valid: %s\n", au.BrightRed(err))
+		} else {
+			responseValid = true
+		}
+	}
+	return response, nil
+}

shared/promptutil/validate.go

@@ -0,0 +1,98 @@
+package promptutil
+
+import (
+	"errors"
+	"strconv"
+	"unicode"
+
+	strongPasswords "github.com/nbutton23/zxcvbn-go"
+)
+
+const (
+	// Constants for passwords.
+	minPasswordLength = 8
+	// Min password score of 3 out of 5 based on the https://github.com/nbutton23/zxcvbn-go
+	// library for strong-entropy password computation.
+	minPasswordScore = 3
+)
+
+// NotEmpty is a validation function to make sure the input given isn't empty and is valid unicode.
+func NotEmpty(input string) error {
+	if input == "" {
+		return errors.New("input cannot be empty")
+	}
+	if !IsValidUnicode(input) {
+		return errors.New("not valid unicode")
+	}
+	return nil
+}
+
+// ValidateNumber makes sure the entered text is a valid number.
+func ValidateNumber(input string) error {
+	_, err := strconv.Atoi(input)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// ValidateConfirmation makes sure the entered text is the user confirming.
+func ValidateConfirmation(input string) error {
+	if input != "Y" && input != "y" {
+		return errors.New("please confirm the above text")
+	}
+	return nil
+}
+
+// IsValidUnicode checks if an input string is a valid unicode string comprised of only
+// letters, numbers, punctuation, or symbols.
+func IsValidUnicode(input string) bool {
+	for _, char := range input {
+		if !(unicode.IsLetter(char) ||
+			unicode.IsNumber(char) ||
+			unicode.IsPunct(char) ||
+			unicode.IsSymbol(char)) {
+			return false
+		}
+	}
+	return true
+}
+
+// ValidatePasswordInput validates a strong password input for new accounts,
+// including a min length, at least 1 number and at least
+// 1 special character.
+func ValidatePasswordInput(input string) error {
+	var (
+		hasMinLen  = false
+		hasLetter  = false
+		hasNumber  = false
+		hasSpecial = false
+	)
+	if len(input) >= minPasswordLength {
+		hasMinLen = true
+	}
+	for _, char := range input {
+		switch {
+		case !(unicode.IsLetter(char) || unicode.IsNumber(char) || unicode.IsPunct(char) || unicode.IsSymbol(char)):
+			return errors.New("password must only contain alphanumeric characters, punctuation, or symbols")
+		case unicode.IsLetter(char):
+			hasLetter = true
+		case unicode.IsNumber(char):
+			hasNumber = true
+		case unicode.IsPunct(char) || unicode.IsSymbol(char):
+			hasSpecial = true
+		}
+	}
+	if !(hasMinLen && hasLetter && hasNumber && hasSpecial) {
+		return errors.New(
+			"password must have more than 8 characters, at least 1 special character, and 1 number",
+		)
+	}
+	strength := strongPasswords.PasswordStrength(input, nil)
+	if strength.Score < minPasswordScore {
+		return errors.New(
+			"password is too easy to guess, try a stronger password",
+		)
+	}
+	return nil
+}