Shell validators

Shell library to validate user inputs.

Table of Contents

• Shell validators
  • Table of Contents
  • How to use?
    • Prerequisites
    • Installation
  • Features
    • Customization
      • Define exit code
    • Validators
      • Validate that directory exists
      • Validate enum
      • Validate that file exists
      • Validate semver
      • Validate tool installed
  • Hints
  • Contributions

How to use?

Prerequisites

The following tools have to be available on a machine prior using this library:

• bash >=4.0

Installation

bpkg install fabasoad/sh-validators

More information on installation options you can find here.

Features

Customization

Define exit code

It is possible to set preferred custom exit code on failure via environment variable:

• Name: FABASOAD_VALIDATORS_CONFIG_EXIT_CODE.
• Type: number
• Default: 1

Examples:

# Default exit code
$ ./fabasoad-validate-dir-exists "./abc"
"./abc" is not a directory or does not exist.
$ echo $?
1
# Custom exit code
$ FABASOAD_VALIDATORS_CONFIG_EXIT_CODE=32 ./fabasoad-validate-dir-exists "./abc"
"./abc" is not a directory or does not exist.
$ echo $?
32
# Invalid exit code
$ FABASOAD_VALIDATORS_CONFIG_EXIT_CODE=invalid ./fabasoad-validate-dir-exists "./abc"
"./abc" is not a directory or does not exist.
$ echo $?
1

Validators

Validate that directory exists

Validates that passed value is a path to an existing directory. Examples:

# Positive case
$ ./fabasoad-validate-dir-exists "this-dir-exists"
$ echo $?
0
# Negative case with passing a file instead of a directory
$ ./fabasoad-validate-dir-exists "this-file-exists.txt"
"this-file-exists.txt" is not a directory or does not exist.
$ echo $?
1
# Negative case without setting parameter name
$ ./fabasoad-validate-dir-exists "this-dir-does-not-exist"
"this-dir-does-not-exist" is not a directory or does not exist.
$ echo $?
1
# Negative case with setting parameter name
$ ./fabasoad-validate-dir-exists "this-dir-does-not-exist" "my-param"
"my-param" parameter is invalid. "this-dir-does-not-exist" is not a directory or does not exist.
$ echo $?
1

Validate enum

Validates string to be one of the possible values (emulating enum data type). Examples:

# Positive case
$ ./fabasoad-validate-enum "true" "true,false"
$ echo $?
0
# Negative case without setting parameter name
$ ./fabasoad-validate-enum "wrong" "true,false"
"wrong" is invalid. Possible values: true, false.
$ echo $?
1
# Negative case with setting parameter name
$ ./fabasoad-validate-enum "wrong" "true,false" "my-param"
"my-param" parameter is invalid. "wrong" is invalid. Possible values: true, false.
$ echo $?
1

Validate that file exists

Validates that passed value is a path to an existing file. Examples:

# Positive case
$ ./fabasoad-validate-file-exists "this-file-exists.txt"
$ echo $?
0
# Negative case with passing a directory instead of a file
$ ./fabasoad-validate-file-exists "this-dir-exists"
"this-dir-exists" is not a file or does not exist.
$ echo $?
1
# Negative case without setting parameter name
$ ./fabasoad-validate-file-exists "this-file-does-not-exist.txt"
"this-file-does-not-exist.txt" is not a file or does not exist.
$ echo $?
1
# Negative case with setting parameter name
$ ./fabasoad-validate-file-exists "this-file-does-not-exist.txt" "my-param"
"my-param" parameter is invalid. "this-file-does-not-exist.txt" is not a file or does not exist.
$ echo $?
1

Validate semver

Validates value to be a valid semver string. Examples:

# Positive case
$ ./fabasoad-validate-semver "1.2.3"
$ echo $?
0
# Negative case without setting parameter name
$ ./fabasoad-validate-semver "alpha.beta.1"
"alpha.beta.1" is not a valid semver.
$ echo $?
1
# Negative case with setting parameter name
$ ./fabasoad-validate-semver "alpha.beta.1" "my-param"
"my-param" parameter is invalid. "alpha.beta.1" is not a valid semver.
$ echo $?
1

Validate tool installed

Validates that tool is installed on the machine. Examples:

# Positive case (assuming jq is installed)
$ ./fabasoad-validate-tool-installed "jq"
$ echo $?
0
# Negative case without setting parameter name
$ ./fabasoad-validate-tool-installed "abc"
"abc" is not installed on the current machine.
$ echo $?
1
# Negative case with setting parameter name
$ ./fabasoad-validate-tool-installed "abc" "my-param"
"my-param" parameter is invalid. "abc" is not installed on the current machine.
$ echo $?
1

Hints

If you want to redirect error message to your internal logic:

set +e
err_msg=$(./fabasoad-validate-dir-exists "abc" 2>&1 >/dev/null)
exit_code="$?"
if [ "${exit_code}" -ne 0 ]; then
  printf "[ERR] [%s] %s\n" "$(date +'%Y-%m-%d %T')" "${err_msg}"
fi
set -e
exit "${exit_code}"
# Output
[ERR] [2025-01-25 19:11:36] "abc" is not a directory or does not exist.

Contributions