Utils.EnvironmentManager

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The EnvironmentManager namespace now provides a class EnvManager that uses AutoMapper package, for retrieving environment variable values and performing type conversions.

Note This documentation assumes a basic understanding of AutoMapper library. AutoMapper docs

Initialization

EnvManager initialization can be achieved with or without a custom AutoMapper configuration:

1. Without a custom configuration:

var manager = new EnvManager();

2. With a custom configuration:

var manager = new EnvManager(config: config);

Methods

GetEnvironmentValue

The method retrieves the value of the specified environment variable and converts it to the desired type using AutoMapper.

Signature:

public object GetEnvironmentValue(Type type, string variableName, bool raiseException = false)

Parameters:

• type (Type): The type to which the environment variable's value should be converted.
• variableName (string): The name of the environment variable.
• raiseException (bool, optional): Specifies whether to raise an exception if the environment variable is null or empty, or when the conversion fails. Defaults to false.

Returns:

• object: The converted value of the environment variable.

GetEnvironmentValue<T>

This method retrieves the value of the specified environment variable and converts it to the specified type T.

Signature:

public T GetEnvironmentValue<T>(string variableName, bool raiseException = false)

Parameters:

• variableName (string): The name of the environment variable.
• raiseException (bool, optional): Specifies whether to raise an exception if the environment variable is null or empty, or when the conversion fails. Defaults to false.

Returns:

• T: The converted value of the environment variable.

Adding Custom Mappings

The library now uses AutoMapper for type conversions. Therefore, to add custom type conversions, you can utilize the EnvManagerMappingConfigurator class.

Example:

var config = new EnvManagerMappingConfigurator()
    .CreateMapFor(x => DateTime.ParseExact(x, "dd-MM-yyyy HH:mm", CultureInfo.InvariantCulture))
    .CreateMapFor(x => Enum.Parse<MyEnumeration>(x, true))
    .Build();

var manager = new EnvManager(config: config);

DateTime customDateFormat = manager.GetEnvironmentValue<DateTime>("CUSTOM_DATE_FORMAT");

In this example, a custom date format is added using the CreateMapFor method. Also in this example adding mapping for a MyEnumeration enum. Once the custom mappings are added, the configuration is built and passed to the EnvManager.

Logging

EnvManager incorporates logging through the Microsoft's ILogger interface, providing insights into the operations and potential issues while working with environment variables.

Logger Initialization

You can pass an instance of ILogger<EnvManager> when creating the EnvManager. If no logger is provided, a default instance of NullLogger<EnvManager> is used, which means no logging output will be produced.

Example:

var logger = new LoggerFactory().CreateLogger<EnvManager>();
var manager = new EnvManager(logger: logger);

If you wish to use the default logger (which won't produce any log output):

var manager = new EnvManager();

Logging Scenarios

Here are some situations where the EnvManager logs information:

1. Warning: If an environment variable is null or empty and the raiseException parameter is set to false, a warning log will be generated.

• Log Message: "Environment variable '{VariableName}' is null or empty."

2. Error: If there's a failed conversion of an environment variable and the raiseException parameter is set to false, an error log will be created.

• Log Message: "Failed to convert environment variable '{VariableName}' to type '{Type}'. Returning default value."

In both scenarios, the actual variable name and type (if applicable) will replace the placeholders {VariableName} and {Type}.