dnscontrol/documentation/language-reference/top-level-functions/require.md
Tom Limoncelli 8eb3c65050
FEATURE: Enable "require()" function to accept json5 files (#3003)
Co-authored-by: charliez0 <charliez0sp@gmail.com>
2024-06-11 15:27:11 -04:00

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3.1 KiB
Markdown

---
name: require
parameters:
- path
ts_ignore: true
---
`require(...)` loads the specified JavaScript, JSON, or JSON5 file, allowing
to split your configuration across multiple files.
A better name for this function might be "include".
If the supplied `path` string ends with `.js`, the file is interpreted
as JavaScript code, almost as though its contents had been included in
the currently-executing file. If the path string ends with `.json` or `.json5` (case insensitive),
`require()` returns the `JSON.parse()` of the file's contents.
If the path string begins with a `./`, it is interpreted relative to
the currently-loading file (which may not be the file where the
`require()` statement is, if called within a function). Otherwise it
is interpreted relative to the program's working directory at the time
of the call.
### Example 1: Simple
In this example, we separate our macros in one file, and put groups of domains
in 3 other files. The result is a cleaner separation of code vs. domains.
{% code title="dnsconfig.js" %}
```javascript
require("lib/macros.json");
require("domains/main.json");
require("domains/parked.json");
require("domains/otherstuff.json");
```
{% endcode %}
### Example 2: Complex
Here's a more complex example:
{% code title="dnsconfig.js" %}
```javascript
require("kubernetes/clusters.js");
D("example.com", REG_MY_PROVIDER, DnsProvider(DSP_MY_PROVIDER),
IncludeKubernetes(),
END);
```
{% endcode %}
{% code title="kubernetes/clusters.js" %}
```javascript
require("./clusters/prod.js");
require("./clusters/dev.js");
function IncludeKubernetes() {
return [includeK8Sprod(), includeK8Sdev()];
}
```
{% endcode %}
{% code title="kubernetes/clusters/prod.js" %}
```javascript
function includeK8Sprod() {
return [
// ...
];
}
```
{% endcode %}
{% code title="kubernetes/clusters/dev.js" %}
```javascript
function includeK8Sdev() {
return [
// ...
];
}
```
{% endcode %}
### Example 3: JSON and JSON5
Requiring JSON files initializes variables:
{% code title="dnsconfig.js" %}
```javascript
var domains = require("./domain-ip-map.json")
var REG_MY_PROVIDER = NewRegistrar("none");
var DSP_MY_DNSSERVER = NewDnsProvider("none");
for (var domain in domains) {
D(domain, REG_MY_PROVIDER, DSP_MY_DNSSERVER,
A("@", domains[domain])
);
}
```
{% endcode %}
{% code title="domain-ip-map.json" %}
```javascript
{
"example.com": "1.1.1.1",
"other-example.com``": "5.5.5.5"
}
```
{% endcode %}
JSON5 works the same way, but the filename ends in `.json5`. (Note: JSON5
features are supported whether the filename ends with `.json` or `.json5`.
However please don't rely on JSON5 features in a `.json` file as this may
change some day.)
# Notes
`require()` is *much* closer to PHP's `include()` function than it
is to node's `require()`.
Node's `require()` only includes a file once.
In contrast, DNSControl's `require()` is actually an imperative command to
load the file and execute the code or parse the data from it. For example if
two files both `require("./tools.js")`, then it will be
loaded twice, whereas in node.js it would only be loaded once.