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https://github.com/gilbert/zaml
The Final Form of configuration files
https://github.com/gilbert/zaml
configuration schema validation yaml
Last synced: about 1 month ago
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The Final Form of configuration files
- Host: GitHub
- URL: https://github.com/gilbert/zaml
- Owner: gilbert
- License: mit
- Created: 2018-11-15T20:04:15.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2021-10-24T01:56:14.000Z (almost 3 years ago)
- Last Synced: 2024-07-31T23:56:57.870Z (about 2 months ago)
- Topics: configuration, schema, validation, yaml
- Language: TypeScript
- Homepage: https://gilbert.github.io/zaml/editor.html
- Size: 155 KB
- Stars: 46
- Watchers: 4
- Forks: 2
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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[](https://www.npmjs.com/package/zaml)
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# Zaml – The Final Form of Configuration Files
JSON is tedious to type for humans. YAML is [error-prone and hard to parse](https://arp242.net/weblog/yaml_probably_not_so_great_after_all.html). TOML is verbose for nested data structures.
Enter Zaml.
Zaml is the [final form](https://youtu.be/zGdFXUJ1o1U?t=4m17s) of configuration files. It's a zero-dependency, type-checking machine that points out your errors as graceful as a dove. It takes the pain out of your gain.
Never again deal with the boilerplate of validating config data structures. Make config easier for you *and* your users.
Zaml isn't even an ancronym. That's how good it is.
## Install
npm install zaml
or
yarn add zaml
or
[Check out the online editor](https://gilbert.github.io/zaml/editor.html)!
## Table of Contents
- [Introduction](#introduction)
- [Syntax & Features](#features)
- [Using the JavaScript API](#javascript-api)
- [Spec](#spec)
- [Roadmap](#roadmap)
- [Contributing](#contributing)
## Introduction
Zaml's syntax is clean, effective, and not obsessed with your shift key:
```js
import {parse} from 'zaml'
var schema = '{ fileRoots: { dev:list, prod:list } }'
var zamlContent = `
# This is Zaml!
# You'd probably load this from a file instead.
fileRoots {
dev {
$HOME/dev/services
$HOME/dev/states
}
prod {
$HOME/prod/services-2
$HOME/prod/states
}
}
`
var result = parse(zamlContent, schema, { vars: process.env })
console.log("Got result:", result)
```
(You can [run this example in your browser](https://flems.io/#0=N4IgZglgNgpgziAXAbVAOwIYFsZJAOgAsAXLKEAGhAGMB7NYmBvAHkIGYA+FjAAkIBOMMAF4AOiBLEADnEQB6eQHMIxQgFcARvjpZl0TTAHF5AL2xQJnAFoWW8jJ14B5dTLeJ7HTmLQtpQrwQACbiIEJw6lDEcFb2ATCclCBwMLDUxBD0CIggAIyIAEwALCAAvhTo2Li5+ABWCFR0DEzEeABuGAK85mQAwvSMDLwivAAGvry8AMS8ACqEEHBBy7ZkAISTvJCwAEq0tDG8wFtTwTDtx6dTvAAkABLOALIAovLn7fKpAu0Q1PDXKYPZ5vD5fYgYRixNA3Xhla4BWjBK4w2F3R6veSI4JfIy-f5wAC0hUB6JBWIESPBkIBqKm8NRDImaE63Tg1EIMCwfFGAHJgNtoDB9oc5MdeB9EFAlsQKLxsVKZWU4bzfKzeKzlqMBRiXoheLz5IRaDgHNL-ry4b5iAIAJ4oqbq2huEa8NZQfDSLqpAAUvSgAxaDDl7M53LlAs1cIAlFsIlEYvgIGg0EZ7nMngAZV0AKQAys4AHL4OA25MqMC2n3O2VoKJQCiW3mxtAM6iQjk+owCaMO3jx6JwJMptMZ7Ojbv4HBwOAYJQwXwM5K6aRCgR4TQYQzkKipdKZbJ4QqFRAABnKlRAmBweB0M+Xg1aeHKAF0qNK0ABrHKoK-VPDJucAAe+CaJSADu3z1I0IDqAI5C5FIsgKPI6hoNIn5KDoJpmBYAACp74HkADs+Cnu8MryIBMAgWBtCQUY0HJMQtrSDUKTUAIEDSG0ZQvmUQA))
Parsing the above will result in this data structure:
```json
{
"fileRoots": {
"dev": [
"/home/alice/dev/services",
"/home/alice/dev/states"
],
"prod": [
"/home/alice/prod/services-2",
"/home/alice/prod/states"
]
}
}
```
No quotes, no commas, no colons. Only what you need and nothing else.
Your users also get nice, accurate error messages if they make a mistake writing their config. It's a win-win!
### More Examples
See the [examples/](./examples) folder for more complete syntax & schema examples like the above.
## Features
Here are Zaml's features, each with an example use, from simplest to most complex.
### Comments
A comment is any line that **begins** with `#`
```zaml
# I am a comment
# title This is a comment
title This is # not a comment
```
### bool
A `bool` accepts `true` or `false`
```zaml
# if your schema is {autoCleanup:bool}
autoCleanup true
#=> { "autoCleanup": true }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMBBXALgewMIA2MCAdhgA7IBGOOBAviADTg4YBOEMKImuhxMuQAEWdhm70gA)
### num
A `num` accepts a single numerical value.
```zaml
# if your schema is {port:num}
port 3000
#=> { "port": 3000 }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMADgewE4BdkB2ArnAL4gA04mR2EMKIWeABAMwAMXAOgSKUA)
### str
A `str` is the default type of any unspecified schema key. It accepts any character until it reaches a newline.
If you need multiline strings, you can use triple quotes (`"""`). Zaml will also un-indent your string automatically, just like [Ruby squiggly heredoc](https://infinum.com/the-capsized-eight/multiline-strings-ruby-2-3-0-the-squiggly-heredoc).
```zaml
# if your schema is {title,description} OR {title:str,description} OR etc.
title You, Yourself, and U
description """
A story
...
about your mirror.
"""
#=> { "title": "You, Yourself, and U", "description": "A story\n ...\nabout your mirror." }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMALgS3QGxgGgBMZIAnTABywHsA7AXxH3GoFdSIYUQtcYACAJpt8QtqTAwcAM1EJahfgFUAOgpIRyVTHX4qQ+w7X78AgvzDpqpAJ57jJ-gDoXakwgBGbdPxvj+cJikpNZOaoYGBrQg9EA)
### enum
An `enum` is a [str](#str) with restricted options. It's useful for a "choose one" situation.
```zaml
# if your schema is { paymentMode: enum(test,live) }
paymentMode test
#=> { "paymentMode": "test" }
```
Naturally, if the user provides a value outside the schema, Zaml will reject it and report a readable error message.
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMADggnnGA7AFwFkB7AExmXwFc4AKAmMAgGgBsBLANxgEoBfEC3AlqAJwgwUITDnzFyMAASNmAHTwh+QA)
### kv
A `kv` is a set of key-value pairs. It requires a block.
```zaml
# if your schema is {redirects:kv}
redirects {
/contact /contact-us
/profile/:user /u/:user
}
#=> { "redirects": { "/contact": "/contact-us", "/profile/:user": "/u/:user" } }
```
Please note Zaml **is not** indentation sensitive.
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMATjAJgS0xAFzGQGsA3AXxABpwB7AV3QhhRE13yIAJgAdAHbduAegh0BBBIWGzhYiVMIBaBmEHyADujoAzHABsYI5GpjpRDE2fSCKgkBSA)
### hash block
A `{}` block is a specified inner schema. It translates to a hash that only allows your specified keys.
```zaml
# if your schema is { project: { title, private:bool } }
project {
title My Sweet App
private true
}
#=> { "project": { "title": "My Sweet App", "private": true } }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMADgJwPYCsYQAuywhAloQDYwA0WZAbgoTMgEbbaUC+3IN4bAFdMEGChBY8BQgAJgAHQB2s2eSoxZAWQCesgMoB3GDDkBBdOmWr6TFmsxCYy7spDcgA)
You can also enhance basic types with blocks. This lets you specify cleaner config:
```zaml
# if your schema is { page|multi: str {hide:bool} }
page index.html
page wip.html {
hide true
}
#=> { "page": [
# ["index.html", {}],
# ["index.html", { "hide": true }],
# ] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABABwQcxgHzgFcAbAFwEtl0wyAndYKCgExmQCMB7LkgX3R8QAGnBcidCDBQhsedBQB2bAB4A6KGTgkAOorkx0AdwqYNWkoz3p0zNunpEYevnpB8gA)
### list
A `list` is a sequence of values. A user can write lists either inline or with a block (but not both).
```zaml
# if your schema is {tags:list} OR {tags:list(str)}
# Inline example
tags library, npm, with spaces, js
# Block example
tags {
library
npm
with spaces
js
}
#=> { "tags": ["library", "npm", "with spaces", "js"] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMALgg5mZAbASzHQF8QAacAewFcAnCGFEAYgAIBJAO0K5jZgAPBHAAOeGAB0u7TDjaEARnQR0Anmy6i4bSSADuBdFDZhRCRmD1sAVla7T2AITxUIAawHCxE6XLBswNJsCgTKqmrBmtpRhsam5pZRdtIk0iAkQA)
You can specify the type of items in your list by specifying it in parethesis. When no item type is specified, it is defaulted to `str`, resulting in `list(str)`.
```zaml
# if your schema is { fav_nums:list(num) }
fav_nums 10, 20
#=> { "fav-nums": [10, 20] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABAMwQNwPoB2ArnGMgDYCWYALgBTFwCU6AviADTgD2RAThBgoQ2fIzDoAjAAYO6AEzSAOgRCsgA)
The list item type may also be enhanced with a block. Note that you **must** specify an item type when you do!
```zaml
# if your schema is { users:list(str { admin:bool }) }
users {
andy
beth {
admin true
}
carl
}
#=> { "users": [["andy", {}], ["beth", {admin: true}], ["carl", {}]] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABAVzDATmZAGwEswAXACnN2AQBM5iA7ZAIwHt3CBfASnW4gANOHaZcEGChDY8YdMAA6TdOgRM6AT2WrWMMlAU7Vahs3RlcmGMe7GICXIWV2mIbkA)
Note how a block changes the shape of the above parsed result. This allows you to use destructuring for each list item:
```js
var result = parse(source, schema)
for (let [user, options] of result.users) {
//
// `options` will be {admin: true} for beth,
// and undefined for andy & carl
//
}
```
### inline-list
NOTE: THIS FEATURE IS NOT IMPLEMENTED YET
An inline list a [list](#list) that can only be written inline. This is useful when you want to extend your list with a block:
```zaml
# if your schema is { env|multi: inline-list{require|multi} }
env development, test {
require lib-1
require lib-2
}
env production {
require lib-3
}
# => { "env": [
# [["development", "test"], { "require": ["lib-1","lib-2"] }],
# [["production"], { "require": ["lib-3"] }]
# ]}
```
### key|req
Appending the `|req` attribute to a key will make that key requried.
```zaml
# if your schema is { access_token|req:str }
access_token abc123
```
[Open that in your browser](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABAiEZjAfQBcB7AaxgDsAfAJxgEdkxCb0BfEAGnGIFcacKEFhx4iZSpgBGEAIwAmAMwAdCiDZA) and see what happens when you remove the `access_token` line.
If you specify a `|req` within a basic-type hash block, it will make that block required.
```zaml
# if your schema is { table: str{ id|req: enum(INT,VARCHAR) } }
# This is invalid! It requires a block
# table users
# This works
table users {
id INT
}
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABAFwQIwDYzLpiYBOGAlgCYA+pMAjkTAHYCucAFAJIByAKgBoAagEEASgGEAEhICU6AL5KQg8AHs2pCDBQgAxOn5QKYdKfMsAbgjzUAhOm6Z09Bmwr0zCdPnUQAawAdFkNsfBh0NjAYUjAQkMNjCwB3dVIA+JZwgiiYuPRgEPRzKicBEMUQkEUgA)
### key|multi
Appending the `|multi` attribute to a key allows your users to specify it more than once.
```zaml
# if your schema is {project|multi:{title,type}}
project {
title A
}
project {
title B
type personal
}
#=> { "project": [{ "title": "A" }, { "title": "B", "type": "personal" }] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMADgJwPYCsYQAuAPnAK4A2hAlssDYRTADSECe6MAvlyM+NjKYIMFCCx4ChAATAAOgDtp0hk2kBBRV0UT8RWYuWqY0gEKGVHE50xhsChBS2KQXIA)
`|multi` will also ensure your key is always present, even if the user does not provide any.
```zaml
# if your schema is {project|multi:{title,type}}
# (intentionally left blank)
#=> { "project": [] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMADgJwPYCsYQAuAPnAK4A2hAlssDYRTADSECe6MAvlyM+NjKYIMFCBBcgA)
### tuple
A tuple captures two or more values for a given key, separated by commas. You can specify one in the schema using parenthesis:
```zaml
# if your schema is {redirect:(num,str,str)}
redirect 302, /old, /new
#=> { "redirect": [302, "old", "new"] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMATjAJgS0xAF2QAoA7AVzgBowD0a6BKAXxCvAHtz0IYURMufAQAEAZgAMAJhEB6DgBssc0jADuAHVIhmQA)
Please note that tuples may only contain basic types (`str`, `num`, `bool`, and [enum](#enum)). However, you're free to mix tuples with other features:
```zaml
# if your schema is {redirect|multi:(num,str,str){enableAt}}
redirect 301, /x, /y
redirect 302, /old, /new {
enableAt 2020-10-10
}
#=> { "redirect": [[301, "x", "y"], [302, "/old", "/new", { "enableAt": "2020-10-10" }]] }
```
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMABAJxgEwJbYQAuAPnAK4A2ReyAFAHblwA0YRmbHAlMDAwgBGlGAEEiAX3QSQLcAHtymCDBQhs+QkXQBmAAwBGdAHoAHiYCeAHQY2NBGMV16ATCfmUcJhjADu6YBt0dH4hEXF0F1c9AFoDWPibCRsQCSA)
### array block
A `[]` block is an array of items from a specified schema. It translates to an array of key-value tuples.
```zaml
# if your schema is {sidebar:[header,link:(str,str)]}
sidebar {
header Site
link Home /
link About Us, /about
header Account
link Settings, /account/settings
}
#=> { "sidebar": [
# ["header", "Site"], ["link", ["Home", "/"]], ["link", ["About Us", "/about"]],
# ["header", "Account"], ["link", ["Settings", "/account/settings"]]
# ] }
```
Note how a block changes the shape of the above parsed result. This allows you to use destructuring for each item:
[View this example in the online editor](https://gilbert.github.io/zaml/editor.html#s=N4IgzgxgFgpgtgQxALhMMBLAJjARggJ2QG1YEcCAaAGwwDsBrZACjABcr2CBKAXQF8QlcAHsArgQgwU4bHkIACYAB06ChWQoKAyhjYxV62owUAJEXBiUFAekMLjDBQEFc4tgoCqYazYRuxNlV7TRgCFwgIcTogtQd6J20YNjZ6AHMfWwRI6LYbMGTUugzVflUQfiA)
```js
var result = parse(source, schema)
for (let [type, value] of result.sidebar) {
//
// `type` will be "header" or "link",
// whereas `value` will be a string (for header) or an array of size 2 (for link).
//
}
```
## JavaScript API
- [parse(source, schema [, parseOptions])](#parse)
### parse
The primary way you interact with Zaml is through its `parse` function. This is how you convert Zaml source to a JavaScript data structure.
`parse` takes two, maybe three arguments:
1. The Zaml source code (as a string)
2. A schema to parse with (as a string)
3. [Options to enable extra features](#parse-options) (optional parameter)
Here's a full example that includes reading from the file system. Assuming you have the following `my-config.zaml`:
```zaml
host www.example.com
port 443
disallow /admin
disallow /dashboard
```
You can parse the above with this node.js code:
```js
var fs = require('fs')
var zaml = require('zaml')
var source = fs.readFileSync(__dirname + '/my-config.zaml')
var result = zaml.parse(source, 'host,port:num,disallow|multi')
result
//=> { "host": "www.example.com", "port": 443, "disallow": ["/admin", "/dashboard"] }
```
## Parse Options
parseOptions, the third parameter to `parse()`, has the following options:
### vars
Type: `Record`
Each key-value in the provided `vars` object will be made available for users to interpolate using the `$` operator. Example:
```js
let source = `
title Welcome to $APP_NAME
`
zaml.parse(source, 'title:str', {
vars: { APP_NAME: 'My App' }
})
//=> { "title": "Welcome to My App" }
```
Note that you can easily use this feature to provide the user access to their own environment variables in a node.js environment:
```js
zaml.parse(source, 'title:str', {
vars: process.env
})
```
### failOnUndefinedVars
If `vars` is set, then setting `failOnUndefinedVars` to `true` will ensure users cannot use variables that are not defined. This is useful if you want to e.g. ensure a key is always defined:
```js
let source = `
title Welcome to $iDontExist
`
//
// This will throw an error!
//
zaml.parse(source, 'title:str', {
vars: { anyOtherKey: '' },
failOnUndefinedVars: true,
})
```
### caseInsensitiveKeys
Setting this to `true` will allow users to write their config keys in a case-insensitive manner.
### caseInsensitiveEnums
Setting this to `true` will allow users to write [enum](#enum) values in any case.
## Spec
Zaml has not yet reached 1.0, so there is no spec as of yet. However, here's a rough ABNF grammar for the lexer:
```
line = statement | comment
statement = key rest ["{\n" *statement "}"] "\n"
key = string-with-no-whitespace
rest = string-with-no-newlines
comment = "#" rest ("\n" | EOF)
```
After lexing, the parser uses the schema to determine how to parse the `rest` and `*statement` for each statement.
## Roadmap
- New regular expression type
- Allow inline `kv`?
- Allow blocks on `kv`
- New `json` type for arbitrarily-nested json-like data?
- Multiline strings? `text` type?
- Split `num` into `int` and `float`?
- Pluggable validation?
- Default values for tuple types?
- Command line interface?
Regarding the [online editor](https://gilbert.github.io/zaml/editor.html):
- `Get code` button
- Fancy explanations of schema on hover
## Contributing
Interested in contributing? There are several ways you can help:
- Open or discuss an issue for an item on the roadmap
- Implement Zaml in another programming language
- Report any bugs you come across
- Report a behavior that you think *should* be bug
- Help start a spec!
## Developing
```
npm install
npm start # In a separate terminal
npm test
```