Error Handling

Error handling in MoBro plugins follows practices similar to other .NET applications.
Plugins should catch and handle all exceptions and errors that do not render the plugin inoperable.

If an exception is raised and not caught by the plugin's implementation, MoBro will catch and log the exception, then terminate the plugin. The plugin's status will change to Error, and the exception's message will be displayed as the error message.

tip

For situations such as accessing external services or APIs where requests may occasionally fail, it is recommended to implement retry policies or other error-handling mechanisms.
A single failed request, such as one caused by a temporary network issue, should not terminate the plugin.

There are two additional exception-handling options specific to MoBro plugins:

• Manually notifying the MoBro service of an unrecoverable error instead of throwing an exception.
• Throwing a custom PluginException (provided by the SDK) to include additional error details.

Manual Error Notification

The IMoBroService provides dedicated Error functions to notify MoBro about unrecoverable errors.
Calling these functions logs the error, terminates the plugin, and sets its state to Error with the provided error message.

Important: Calling any of these error functions triggers the same behavior as an uncaught exception.

PluginException

The plugin SDK includes several custom PluginException classes for conveying additional error details to MoBro.

PluginException

Represents a generic error that occurs during plugin execution.

Parameters

Name	Type	Description
message	string?	A descriptive error message.
innerException	Exception?	An inner exception providing additional details.

Features

• Allows adding additional details using the AddDetail method.
• Stores additional details in the Details dictionary, where keys and values can provide specific context.

Example

Adding custom details to a generic plugin exception:

try
{
    // Plugin logic...
}
catch (Exception e)
{
    throw new PluginException("A generic plugin error occurred", e)
        .AddDetail("timestamp", DateTime.UtcNow.ToString("o"))
        .AddDetail("pluginVersion", "1.2.3");
}

---

PluginDependencyException

This exception indicates that an error has occurred in an external dependency (e.g., another program, web API, etc.).

Parameters

Name	Type	Description
message	string?	The error message
innerException	Exception?	An inner exception providing additional details

Example

In this example, _apiClient implements retries with exponential backoff:

try
{
    return _apiClient.GetCoinMarkets(...);
}
catch (Exception e)
{
    _logger.LogError(e, "Failed to fetch data from CoinGecko API");
    throw new PluginDependencyException("Failed to fetch data from CoinGecko: " + e.Message, e);
}

---

PluginSettingsException

This exception indicates that the plugin is missing a required setting or a provided setting value is invalid.

tip

Use the IMoBroSettings.GetValue<T>(string): T function to automatically raise an appropriate PluginSettingsException when a setting with the given key does not exist or lacks a valid value.

Parameters

Name	Type	Description
field	string?	The key of the setting field causing the error
message	string?	The error message
innerException	Exception?	An inner exception providing additional details

Example

throw new PluginSettingsException("update_frequency", "Invalid update frequency", null);

---

MoBroItemValidationException

Indicates that a passed IMoBroItem was invalid.

Parameters

Name	Type	Description
mobroItemId	string	The ID of the invalid IMoBroItem.
field	string?	The name of the invalid field (if applicable).
message	string?	A descriptive error message.
innerException	Exception?	An inner exception providing additional details.

Features

• Adds additional details to the exception using itemId and optionally field.

Example

try
{
    ValidateItem(item);
}
catch (Exception e)
{
    throw new MoBroItemValidationException("item_123", "fieldName", "Invalid field value", e);
}

---

MetricValueValidationException

Indicates that an invalid value was passed for a metric.

Parameters

Name	Type	Description
metricId	string	The ID of the metric causing the exception.
message	string?	A descriptive error message.
innerException	Exception?	An inner exception providing additional details.

Features

• Adds additional details to the exception using metricId.

Example

try
{
    LogMetricValue(metricId, value);
}
catch (Exception e)
{
    throw new MetricValueValidationException("metric_456", "Invalid value for metric", e);
}