feat(influxdb3): add TOML configuration documentation to plugin library

- Add TOML configuration section to plugins-library index explaining usage
- Add TOML config tables to all official plugin documentation files
- Standardize TOML section format across plugins with config_file_path parameter
- Update system-metrics plugin moved from examples to official
- Remove redundant config_file_path from individual parameter tables
- Ensure consistent placement before Installation/Requirements sections
- Fix linting: replace 'e.g.' with 'for example' in system-metrics.md

This completes the TOML configuration documentation updates from PR 6244

Author: jstirnaman

content/shared/influxdb3-plugins/plugins-library/_index.md

@@ -15,3 +15,46 @@ Plugins in this library include a JSON metadata schema in a docstring header tha
 
 - the [InfluxDB 3 Explorer UI](/influxdb3/explorer/) to display and configure the plugin
 - automated testing and validation of plugins in the repository
+
+## Using TOML Configuration Files
+
+Many plugins in this library support using TOML configuration files to specify all plugin arguments. This is useful for complex configurations or when you want to version control your plugin settings.
+
+### Important Requirements
+
+**To use TOML configuration files, you must set the `PLUGIN_DIR` environment variable in the {{% product-name %}} host environment.** This is required in addition to the `--plugin-dir` flag when starting {{% product-name %}}:
+
+- `--plugin-dir` tells {{% product-name %}} where to find plugin Python files
+- `PLUGIN_DIR` environment variable tells the plugins where to find TOML configuration files
+
+### Set up TOML Configuration
+
+1. **Start {{% product-name %}} with the PLUGIN_DIR environment variable set**:
+   ```bash
+   PLUGIN_DIR=~/.plugins influxdb3 serve --node-id node0 --object-store file --data-dir ~/.influxdb3 --plugin-dir ~/.plugins
+   ```
+
+2. **Copy or create a TOML configuration file in your plugin directory**:
+   ```bash
+   # Example: copy a plugin's configuration template
+   cp plugin_config_example.toml ~/.plugins/my_config.toml
+   ```
+
+3. **Edit the TOML file** to match your requirements. The TOML file should contain all the arguments defined in the plugin's argument schema.
+
+4. **Create a trigger with the `config_file_path` argument**:
+   When creating a trigger, specify the `config_file_path` argument to point to your TOML configuration file.
+   
+   - Specify only the filename (not the full path)
+   - The file must be located under `PLUGIN_DIR`
+
+   ```bash
+   influxdb3 create trigger \
+     --database mydb \
+     --plugin-filename plugin_name.py \
+     --trigger-spec "every:1d" \
+     --trigger-arguments config_file_path=my_config.toml \
+     my_trigger_name
+   ```
+
+For more information on using TOML configuration files, see the project [README](https://github.com/influxdata/influxdb3_plugins/blob/master/README.md).

content/shared/influxdb3-plugins/plugins-library/examples/wal-plugin.md

@@ -10,15 +10,9 @@ The plugin can optionally double-count rows for a specified table to demonstrate
 |-----------|------|---------|-------------|
 | `double_count_table` | string | none | Table name for which to double the row count in write reports (for testing/demonstration) |
 
-## Requirements
+## Installation steps
 
-### Software requirements
-- InfluxDB 3 Core or InfluxDB 3 Enterprise with Processing Engine enabled
-- No additional Python packages required (uses built-in libraries)
-
-### Installation steps
-
-1. Start InfluxDB 3 with plugin support:
+1. Start {{% product-name %}} with the Processing Engine enabled (`--plugin-dir /path/to/plugins`)
    ```bash
    influxdb3 serve \
      --node-id node0 \

content/shared/influxdb3-plugins/plugins-library/official/basic-transformation.md

@@ -31,22 +31,43 @@ The plugin supports both scheduled batch processing of historical data and real-
 | `excluded_fields` | string | none | Dot-separated list of fields to exclude |
 | `filters` | string | none | Query filters. Format: `'field:"operator value"'` |
 
-### Advanced parameters
+### TOML configuration
 
-| Parameter | Type | Default | Description |
-|-----------|------|---------|-------------|
-| `config_file_path` | string | none | Path to TOML config file relative to PLUGIN_DIR |
+| Parameter          | Type   | Default | Description                                                                      |
+|--------------------|--------|---------|----------------------------------------------------------------------------------|
+| `config_file_path` | string | none    | TOML config file path relative to `PLUGIN_DIR` (required for TOML configuration) |
+
+*To use a TOML configuration file, set the `PLUGIN_DIR` environment variable and specify the `config_file_path` in the trigger arguments.* This is in addition to the `--plugin-dir` flag when starting InfluxDB 3.
+
+#### Example TOML configurations
 
-## Requirements
+- [basic_transformation_config_scheduler.toml](https://github.com/influxdata/influxdb3_plugins/blob/master/influxdata/basic_transformation/basic_transformation_config_scheduler.toml) - for scheduled triggers
+- [basic_transformation_config_data_writes.toml](https://github.com/influxdata/influxdb3_plugins/blob/master/influxdata/basic_transformation/basic_transformation_config_data_writes.toml) - for data write triggers
+
+```bash
+influxdb3 create trigger \
+ --database mydb \
+ --plugin-filename basic_transformation.py \
+ --trigger-spec "every:1d" \
+ --trigger-arguments config_file_path=basic_transformation_config_scheduler.toml \
+ basic_transform_trigger
+```
 
-### Software requirements
-- InfluxDB 3 Core or Enterprise with Processing Engine enabled
-- Python packages:
-  - `pint` (for unit conversions)
+For more information on using TOML configuration files, see the Using TOML Configuration Files section in the [influxdb3_plugins
+/README.md](https://github.com/influxdata/influxdb3_plugins/blob/master/README.md).
 
-### Installation steps
+## Schema requirements
 
-1. Start InfluxDB 3 with plugin support:
+The plugin assumes that the table schema is already defined in the database, as it relies on this schema to retrieve field and tag names required for processing.
+
+> [!WARNING]
+> #### Requires existing schema
+>
+> By design, the plugin returns an error if the schema doesn't exist or doesn't contain the expected columns.
+
+## Installation steps
+
+1. Start {{% product-name %}} with the Processing Engine enabled (`--plugin-dir /path/to/plugins`)
    ```bash
    influxdb3 serve \
      --node-id node0 \
@@ -56,6 +77,9 @@ The plugin supports both scheduled batch processing of historical data and real-
    ```
 
 2. Install required Python packages:
+
+   - `pint` (for unit conversions)
+
    ```bash
    influxdb3 install package pint
    ```
@@ -174,52 +198,6 @@ influxdb3 create trigger \
   status_updater
 ```
 
-## Using TOML Configuration Files
-
-This plugin supports using TOML configuration files to specify all plugin arguments. This is useful for complex configurations or when you want to version control your plugin settings.
-
-### Important Requirements
-
-**To use TOML configuration files, you must set the `PLUGIN_DIR` environment variable in the InfluxDB 3 host environment.** This is required in addition to the `--plugin-dir` flag when starting InfluxDB 3:
-
-- `--plugin-dir` tells InfluxDB 3 where to find plugin Python files
-- `PLUGIN_DIR` environment variable tells the plugins where to find TOML configuration files
-
-### Setting Up TOML Configuration
-
-1. **Start InfluxDB 3 with the PLUGIN_DIR environment variable set**:
-   ```bash
-   PLUGIN_DIR=~/.plugins influxdb3 serve --node-id node0 --object-store file --data-dir ~/.influxdb3 --plugin-dir ~/.plugins
-   ```
-
-2. **Copy the example TOML configuration file to your plugin directory**:
-   ```bash
-   cp basic_transformation_config_scheduler.toml ~/.plugins/
-   # or for data writes:
-   cp basic_transformation_config_data_writes.toml ~/.plugins/
-   ```
-
-3. **Edit the TOML file** to match your requirements. The TOML file contains all the arguments defined in the plugin's argument schema (see the JSON schema in the docstring at the top of basic_transformation.py).
-
-4. **Create a trigger using the `config_file_path` argument**:
-   ```bash
-   influxdb3 create trigger \
-     --database mydb \
-     --plugin-filename basic_transformation.py \
-     --trigger-spec "every:1d" \
-     --trigger-arguments config_file_path=basic_transformation_config_scheduler.toml \
-     basic_transform_trigger
-   ```
-
-### Important Notes
-- The `PLUGIN_DIR` environment variable must be set when starting InfluxDB 3 for TOML configuration to work
-- When using `config_file_path`, specify only the filename (not the full path)
-- The TOML file must be located in the directory specified by `PLUGIN_DIR`
-- All parameters in the TOML file will override any command-line arguments
-- Example TOML configuration files are provided:
-  - `basic_transformation_config_scheduler.toml` - for scheduled triggers
-  - `basic_transformation_config_data_writes.toml` - for data write triggers
-
 ## Code overview
 
 ### Files

content/shared/influxdb3-plugins/plugins-library/official/downsampler.md

@@ -36,24 +36,32 @@ Each downsampled record includes metadata about the original data points compres
 | `target_database` | string | "default" | Database for storing downsampled data |
 | `max_retries` | integer | 5 | Maximum number of retries for write operations |
 | `batch_size` | string | "30d" | Time interval for batch processing (HTTP mode only) |
-| `config_file_path` | string | none | Path to TOML config file relative to PLUGIN_DIR |
 
-### Metadata columns
+### TOML configuration
+
+| Parameter          | Type   | Default | Description                                                                      |
+|--------------------|--------|---------|----------------------------------------------------------------------------------|
+| `config_file_path` | string | none    | TOML config file path relative to `PLUGIN_DIR` (required for TOML configuration) |
+
+*To use a TOML configuration file, set the `PLUGIN_DIR` environment variable and specify the `config_file_path` in the trigger arguments.* This is in addition to the `--plugin-dir` flag when starting InfluxDB 3.
+
+#### Example TOML configuration
+
+[downsampling_config_scheduler.toml](downsampling_config_scheduler.toml)
+
+For more information on using TOML configuration files, see the Using TOML Configuration Files section in the [influxdb3_plugins
+/README.md](/README.md).
+
+## Schema management
 
 Each downsampled record includes three additional metadata columns:
 - `record_count`—the number of original points compressed into this single downsampled row
 - `time_from`—the minimum timestamp among the original points in the interval  
 - `time_to`—the maximum timestamp among the original points in the interval
 
-## Requirements
+## Installation steps
 
-### Software requirements
-- InfluxDB 3 Core or Enterprise with Processing Engine enabled
-- Python packages: No additional packages required
-
-### Installation steps
-
-1. Start InfluxDB 3 with plugin support:
+1. Start {{% product-name %}} with the Processing Engine enabled (`--plugin-dir /path/to/plugins`)
    ```bash
    influxdb3 serve \
      --node-id node0 \
@@ -181,46 +189,6 @@ curl -X POST http://localhost:8181/api/v3/engine/downsample \
   }'
 ```
 
-## Using TOML Configuration Files
-
-This plugin supports using TOML configuration files for complex configurations.
-
-### Important Requirements
-
-**To use TOML configuration files, you must set the `PLUGIN_DIR` environment variable in the InfluxDB 3 host environment:**
-
-```bash
-PLUGIN_DIR=~/.plugins influxdb3 serve --node-id node0 --object-store file --data-dir ~/.influxdb3 --plugin-dir ~/.plugins
-```
-
-### Example TOML Configuration
-
-```toml
-# downsampling_config_scheduler.toml
-source_measurement = "cpu"
-target_measurement = "cpu_hourly"
-target_database = "analytics"
-interval = "1h"
-window = "6h"
-calculations = "avg"
-specific_fields = "usage_user.usage_system.usage_idle"
-max_retries = 3
-
-[tag_values]
-host = ["server1", "server2", "server3"]
-```
-
-### Create trigger using TOML config
-
-```bash
-influxdb3 create trigger \
-  --database mydb \
-  --plugin-filename downsampler.py \
-  --trigger-spec "every:1h" \
-  --trigger-arguments config_file_path=downsampling_config_scheduler.toml \
-  downsample_trigger
-```
-
 ## Code overview
 
 ### Files

content/shared/influxdb3-plugins/plugins-library/official/forecast-error-evaluator.md

@@ -68,18 +68,24 @@ It includes debounce logic to suppress transient anomalies and supports multi-ch
 | `twilio_from_number` | string | required | Twilio sender number (for example, `"+1234567890"`) |
 | `twilio_to_number` | string | required | Recipient number (for example, `"+0987654321"`) |
 
-## Requirements
+### TOML configuration
 
-### Software requirements
-- InfluxDB 3 Core or Enterprise with Processing Engine enabled
-- Notification Sender Plugin for InfluxDB 3 (required for notifications)
-- Python packages:
-  - `pandas` (for data processing)
-  - `requests` (for HTTP notifications)
+| Parameter          | Type   | Default | Description                                                                      |
+|--------------------|--------|---------|----------------------------------------------------------------------------------|
+| `config_file_path` | string | none    | TOML config file path relative to `PLUGIN_DIR` (required for TOML configuration) |
+
+*To use a TOML configuration file, set the `PLUGIN_DIR` environment variable and specify the `config_file_path` in the trigger arguments.* This is in addition to the `--plugin-dir` flag when starting InfluxDB 3.
+
+#### Example TOML configuration
+
+[forecast_error_config_scheduler.toml](https://github.com/influxdata/influxdb3_plugins/blob/master/influxdata/forecast_error_evaluator/forecast_error_config_scheduler.toml)
+
+For more information on using TOML configuration files, see the Using TOML Configuration Files section in the [influxdb3_plugins
+/README.md](https://github.com/influxdata/influxdb3_plugins/blob/master/README.md).
 
-### Installation steps
+## Installation steps
 
-1. Start InfluxDB 3 with plugin support:
+1. Start {{% product-name %}} with the Processing Engine enabled (`--plugin-dir /path/to/plugins`)
    ```bash
    influxdb3 serve \
      --node-id node0 \
@@ -89,12 +95,17 @@ It includes debounce logic to suppress transient anomalies and supports multi-ch
    ```
 
 2. Install required Python packages:
+
+  - `pandas` (for data processing)
+  - `requests` (for HTTP notifications)
+
    ```bash
    influxdb3 install package pandas
    influxdb3 install package requests
    ```
 
 3. Install the Notification Sender Plugin (required):
+
    ```bash
    # Ensure notifier plugin is available in ~/.plugins/
    ```

content/shared/influxdb3-plugins/plugins-library/official/influxdb-to-iceberg.md

@@ -53,27 +53,40 @@ The plugin supports both scheduled batch transfers of historical data and on-dem
 - The `time` column is converted to `datetime64[us]` for Iceberg compatibility
 - Tables are created in format: `<namespace>.<table_name>`
 
-## Requirements
+## Schema requirements
 
-### Software requirements
-- InfluxDB 3 Core or Enterprise with Processing Engine enabled
-- Python packages:
-  - `pandas` (for data manipulation)
-  - `pyarrow` (for Parquet support)
-  - `pyiceberg[catalog-options]` (for Iceberg integration)
+The plugin assumes that the Iceberg table schema is already defined in the database, as it relies on this schema to retrieve field and tag names required for processing.
 
-### Installation steps
+> [!WARNING]
+> #### Requires existing schema
+>
+> By design, the plugin returns an error if the schema doesn't exist or doesn't contain the expected columns. 
 
-1. Start InfluxDB 3 with plugin support:
-   ```bash
-   influxdb3 serve \
-     --node-id node0 \
-     --object-store file \
-     --data-dir ~/.influxdb3 \
-     --plugin-dir ~/.plugins
-   ```
+### TOML configuration
+
+| Parameter          | Type   | Default | Description                                                                      |
+|--------------------|--------|---------|----------------------------------------------------------------------------------|
+| `config_file_path` | string | none    | TOML config file path relative to `PLUGIN_DIR` (required for TOML configuration) |
+
+*To use a TOML configuration file, set the `PLUGIN_DIR` environment variable and specify the `config_file_path` in the trigger arguments.* This is in addition to the `--plugin-dir` flag when starting InfluxDB 3.
+
+#### Example TOML configuration
+
+[influxdb_to_iceberg_config_scheduler.toml](https://github.com/influxdata/influxdb3_plugins/blob/master/influxdata/influxdb_to_iceberg/influxdb_to_iceberg_config_scheduler.toml)
+
+For more information on using TOML configuration files, see the Using TOML Configuration Files section in the [influxdb3_plugins
+/README.md](https://github.com/influxdata/influxdb3_plugins/blob/master/README.md).
+ 
+## Installation steps
+
+1. Start {{% product-name %}} with the Processing Engine enabled (`--plugin-dir /path/to/plugins`)
 
 2. Install required Python packages:
+
+   - `pandas` (for data manipulation)
+   - `pyarrow` (for Parquet support)
+   - `pyiceberg[catalog-options]` (for Iceberg integration)
+  
    ```bash
    influxdb3 install package pandas
    influxdb3 install package pyarrow