# Simple Otel Plugin Installation

## Installation

To install or update the Simple Otel plugin, run the following command from the root of your WordPress HTML directory:

```sh
curl -sSL https://git.nixc.us/colin/SimpleOtel/raw/branch/main/install.sh | bash
```

## Enabling the Plugin

After running the install script, you need to activate the plugin. You can do this via the WordPress admin dashboard:

1. Log in to your WordPress admin dashboard.
2. Navigate to `Plugins > Installed Plugins`.
3. Find `Simple Otel` in the list and click `Activate`.

Alternatively, you can activate the plugin using WP-CLI:

```sh
wp plugin activate simple-otel --allow-root
```

## What `install.sh` Does

The `install.sh` script performs the following actions:

1. Defines the URL for downloading the `simple-otel.php` file.
2. Creates the target directory (`wp-content/plugins/simple-otel`) if it doesn't exist.
3. Downloads the `simple-otel.php` file into the target directory.
4. Creates a blank `config.php` file if it doesn't already exist and provides a template for configuration.
5. Sets the correct permissions for the `simple-otel.php` and `config.php` files.
6. Prints a message indicating that the Simple Otel plugin has been installed or updated successfully.

## Configuration

After installing the plugin, you can customize its behavior by editing the `config.php` file located in `wp-content/plugins/simple-otel/`.

### Example `config.php`

Here is an example configuration for the `config.php` file:

```php
<?php
// Configuration for Simple Otel plugin
// Add your configurations here

// Set default values using environment variables or fallback to manual configuration
$otel_service_name = getenv('OTEL_SERVICE_NAME') ?: 'default-service-name';
$otel_exporter_otlp_endpoint = getenv('OTEL_EXPORTER_OTLP_ENDPOINT') ?: 'http://localhost:4317';

// Apply configurations
if (isset($GLOBALS['tracer'])) {
    $GLOBALS['tracer']->setAttribute('service.name', $otel_service_name);
    $GLOBALS['tracer']->setAttribute('otel.exporter.otlp.endpoint', $otel_exporter_otlp_endpoint);
}
?>
```

### Explanation

- **Service Name**: Set the name of the service as it will appear in your observability platform. It uses the `OTEL_SERVICE_NAME` environment variable if set; otherwise, it defaults to `default-service-name`.
- **OTLP Endpoint**: Specify the endpoint where SigNoz is running. It uses the `OTEL_EXPORTER_OTLP_ENDPOINT` environment variable if set; otherwise, it defaults to `http://localhost:4317`.

You can add more configuration options as needed. The plugin will include this file and apply the configurations when it initializes.

## Additional Information

For more information on how to use and configure the Simple Otel plugin, please refer to the documentation or visit the [OpenTelemetry PHP documentation](https://opentelemetry.io/docs/php/).

## Example `simple-otel.php` Plugin File

Here is an example of what the `simple-otel.php` plugin file might look like:

```php
<?php
/*
Plugin Name: Simple Otel
Description: Integrate OpenTelemetry with WordPress.
Version: 1.0
Author: Your Name
*/

// Ensure the autoload file is included
require_once __DIR__ . '/vendor/autoload.php';
require_once __DIR__ . '/config.php';

use OpenTelemetry\SDK\Trace\TracerProvider;
use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
use OpenTelemetry\Contrib\OtlpGrpc\Exporter as OtlpGrpcExporter;

// Create an OTLP GRPC exporter
$otlpExporter = new OtlpGrpcExporter([
    'endpoint' => $otel_exporter_otlp_endpoint,
]);

// Create a tracer provider with the OTLP exporter
$tracerProvider = new TracerProvider(
    new SimpleSpanProcessor($otlpExporter)
);

// Register the tracer provider globally
\OpenTelemetry\API\Globals::setTracerProvider($tracerProvider);

// Example usage of the tracer
function otel_trace_example() {
    $tracer = \OpenTelemetry\API\Globals::tracerProvider()->getTracer('example-tracer');
    $span = $tracer->startAndActivateSpan('example-span');
    // Your custom code here
    $span->end();
}
add_action('wp_head', 'otel_trace_example');
?>
```

By following these instructions, you can set up the Simple Otel plugin to send telemetry data directly to SigNoz without the need for an intermediate OpenTelemetry Collector.