---
layout: default
title: The Data Templating Language
---
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<td><img id=big-logo src=img/isologo.svg></td>
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<p>
A data templating language<br>
for app and tool developers
</p>
<ul>
<li>Generate config data</li>
<li>Side-effect free</li>
<li>Organize, simplify, unify</li>
<li>Manage sprawling config</li>
</ul>
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</tr>
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<p>
A simple extension of <a href="http://json.org/">JSON</a><br>
</p>
<ul>
<li>Open source (Apache 2.0)</li>
<li>Familiar syntax</li>
<li>Reformatter, linter</li>
<li>Editor & IDE integrations</li>
<li>Formally specified</li>
</ul>
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<td class=venn-cell><img id=venn src=img/venn.svg></td>
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<p class=center>Eliminate duplication with object-orientation:</p>
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<div class="tab-window-input" id="example1-input">
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</div>
<textarea id=example1-jsonnet autofocus>
// Edit me!
{
person1: {
name: "Alice",
welcome: "Hello " + self.name + "!",
},
person2: self.person1 { name: "Bob" },
}
</textarea>
</div>
<div class="bigarrow">➡</div>
<div class="tab-window-output" id="example1-output">
<div class="tab-header">
<div class=selected onclick="tab_output_click(this, 'example1-json-output')">
output.json
</div>
</div>
<textarea readonly class="selected code-json" id="example1-json-output">
{
"person1": {
"name": "Alice",
"welcome": "Hello Alice!"
},
"person2": {
"name": "Bob",
"welcome": "Hello Bob!"
}
}
</textarea>
</div>
<script>
demo(
'example1-input',
{
'example1-jsonnet': 'example1.jsonnet',
},
'example1.jsonnet',
'example1-output',
false,
false
);
</script>
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</div>
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<p class=center>Or, use functions:</p>
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<div class="tab-window-input" id="example2-input">
<div class="tab-header">
</div>
<textarea id=example2-jsonnet autofocus>
// A function that returns an object.
local Person(name='Alice') = {
name: name,
welcome: 'Hello ' + name + '!',
};
{
person1: Person(),
person2: Person('Bob'),
}
</textarea>
</div>
<div class="bigarrow">➡</div>
<div class="tab-window-output" id="example2-output">
<div class="tab-header">
<div class=selected onclick="tab_output_click(this, 'example2-json-output')">
output.json
</div>
</div>
<textarea readonly class="selected code-json" id="example2-json-output">
{
"person1": {
"name": "Alice",
"welcome": "Hello Alice!"
},
"person2": {
"name": "Bob",
"welcome": "Hello Bob!"
}
}
</textarea>
</div>
<script>
demo(
'example2-input',
{
'example2-jsonnet': 'example2.jsonnet',
},
'example2.jsonnet',
'example2-output',
false,
false
);
</script>
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<p class=center>
Integrate with existing / custom applications.<br>
Generate JSON, YAML, INI, and other formats.
</p>
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<div class="tab-window-input" id="example3-input">
<div class="tab-header">
</div>
<textarea id=example3-jsonnet>
local application = 'my-app';
local module = 'uwsgi_module';
local dir = '/var/www';
local permission = 644;
{
'uwsgi.ini': std.manifestIni({
sections: {
uwsgi: {
module: module,
pythonpath: dir,
socket: dir + '/uwsgi.sock',
'chmod-socket': permission,
callable: application,
logto: '/var/log/uwsgi/uwsgi.log',
},
},
}),
'init.sh': |||
#!/bin/bash
mkdir -p %(dir)s
touch %(dir)s/initialized
chmod %(perm)d %(dir)s/initialized
||| % {dir: dir, perm: permission},
'cassandra.conf': std.manifestYamlDoc({
cluster_name: application,
seed_provider: [
{
class_name: 'SimpleSeedProvider',
parameters: [{ seeds: '127.0.0.1' }],
},
],
}),
}
</textarea>
</div>
<div class="bigarrow">➡</div>
<div class="tab-window-output" id="example3-output">
<div class="tab-header">
<div class=selected onclick="tab_output_click(this, 'example3-yaml-output')">
cassandra.conf
</div>
<div class=unselected onclick="tab_output_click(this, 'example3-sh-output')">
init.sh
</div>
<div class=unselected onclick="tab_output_click(this, 'example3-ini-output')">
uwsgi.ini
</div>
</div>
<textarea readonly class="selected code-json" id="example3-yaml-output">
"cluster_name": "my-app"
"seed_provider":
- "class_name": "SimpleSeedProvider"
"parameters":
- "seeds": "127.0.0.1"
</textarea>
<textarea readonly class="unselected code-json" id="example3-sh-output">
#!/bin/bash
mkdir -p /var/www
touch /var/www/initialized
chmod 644 /var/www/initialized
</textarea>
<textarea readonly class="unselected code-json" id="example3-ini-output">
[uwsgi]
callable = my-app
chmod-socket = 644
logto = /var/log/uwsgi/uwsgi.log
module = uwsgi_module
pythonpath = /var/www
socket = /var/www/uwsgi.sock
</textarea>
</div>
<script>
demo(
'example3-input',
{
'example3-jsonnet': 'example3.jsonnet',
},
'example3.jsonnet',
'example3-output',
true,
true
);
</script>
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</div>
</div>
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<p class=padded>
The name Jsonnet is a portmanteau of JSON and <a
href="http://en.wikipedia.org/wiki/Sonnet"><i>sonnet</i></a>, pronounced "jay sonnet". It
began life early 2014 as a 20% project and was launched on Aug 6. The design is influenced
by several configuration languages internal to Google, and embodies years of experience
configuring some of the world's most complex IT systems. Jsonnet is now used by many
companies and projects. Jsonnet is not an official Google product (experimental or
otherwise), it is just code that happens to be owned by Google.
</p>
</div>
<div class=panel>
<p class=center>
<a href='https://bitnami.com'><img class=user-logo src=img/users/bitnami.png></a>
<a href='https://deepmind.com'><img class=user-logo src=img/users/deepmind.png></a>
<a href='https://www.heptio.com'><img class=user-logo src=img/users/heptio.jpg></a>
<a href='https://kausal.co'><img class=user-logo src=img/users/kausal.svg></a>
</p class=center>
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</div>
</div>
