Class LambdaConfig

The LambdaConfig class is used by the Lambda function to read its configuration settings. LambdaConfig provides hiearachical access to scoped module values using the Item[String] operator. Individual values can be retrieved using the basic Read<T>(String, Func<String, T>, Func<String, T>, Action<T>) method or one of the Read* methods.

Inheritance

System.Object

LambdaConfig

Namespace: LambdaSharp

Assembly: LambdaSharp.dll

Syntax

public sealed class LambdaConfig

Constructors

LambdaConfig(ILambdaConfigSource)

Create a new instance using the provided ILambdaConfigSource instance to read configuration values.

Declaration

public LambdaConfig(ILambdaConfigSource source)

Parameters

Type	Name	Description
ILambdaConfigSource	source	The ILambdaConfigSource instance to read configuration values from.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when source is null.

Properties

Item[String]

Create a new LambdaConfig scoped to a nested section of values.

Declaration

public LambdaConfig this[string name] { get; }

Parameters

Type	Name	Description
System.String	name	Name of the nested section.

Property Value

Type	Description
LambdaConfig	A newly scoped LambdaConfig instance.

Keys

Enumerate all child keys at the current path in the hierarchy.

Declaration

public IEnumerable<string> Keys { get; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<System.String>	Enumeration of all nested keys.

Path

Retrieve the current hierarchy path.

Declaration

public string Path { get; }

Property Value

Type	Description
System.String	Current path.

Methods

Read<T>(String, Func<String, T>, Func<String, T>, Action<T>)

Read the value for a key from ILambdaConfigSource at the current path in the hierarchy.

Declaration

public T Read<T>(string key, Func<string, T> fallback, Func<string, T> convert, Action<T> validate)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Func<System.String, T>	fallback	An optional callback when the value could not be found at the current path.
System.Func<System.String, T>	convert	An optional conversion from string to another type when the value was found.
System.Action<T>	validate	An optional callback to validate the converted value.

Returns

Type	Description
T	The found value.

Type Parameters

Name	Description
T	The type of the value after conversion.

Remarks

This method should rarely be invoked directly. Instead use ReadText(String, Action<String>) and the other convenience methods.

Exceptions

Type	Condition
LambdaConfigMissingKeyException	Thrown when no value is found at key and fallback is null.
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadCommaDelimitedList(String, Action<IEnumerable<String>>)

Read an enumeration of comma-delimited string values for a key at the current path in the hierarchy.

Declaration

public IEnumerable<string> ReadCommaDelimitedList(string key, Action<IEnumerable<string>> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Action<System.Collections.Generic.IEnumerable<System.String>>	validate	An optional callback to validate the value.

Returns

Type	Description
System.Collections.Generic.IEnumerable<System.String>	The found enumeration of string values.

Exceptions

Type	Condition
LambdaConfigMissingKeyException	Thrown when no value is found at key.
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadInt(String, Action<Int32>)

Read the int value for a key at the current path in the hierarchy.

Declaration

public int ReadInt(string key, Action<int> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Action<System.Int32>	validate	An optional callback to validate the value.

Returns

Type	Description
System.Int32	The found int value.

Exceptions

Type	Condition
LambdaConfigMissingKeyException	Thrown when no value is found at key.
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadInt(String, Int32, Action<Int32>)

Read the int value for a key at the current path in the hierarchy.

Declaration

public int ReadInt(string key, int defaultValue, Action<int> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Int32	defaultValue	A value to return if key doesn't exist.
System.Action<System.Int32>	validate	An optional callback to validate the value.

Returns

Type	Description
System.Int32	The found int value.

Exceptions

Type	Condition
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadText(String, Action<String>)

Read the string value for a key at the current path in the hierarchy.

Declaration

public string ReadText(string key, Action<string> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Action<System.String>	validate	An optional callback to validate the value.

Returns

Type	Description
System.String	The found string value.

Exceptions

Type	Condition
LambdaConfigMissingKeyException	Thrown when no value is found at key.
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadText(String, String, Action<String>)

Read the string value for a key at the current path in the hierarchy.

Declaration

public string ReadText(string key, string defaultValue, Action<string> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.String	defaultValue	A value to return if key doesn't exist.
System.Action<System.String>	validate	An optional callback to validate the value.

Returns

Type	Description
System.String	The found string value.

Exceptions

Type	Condition
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadTimeSpan(String, Action<TimeSpan>)

Read the TimeSpan value for a key at the current path in the hierarchy.

Declaration

public TimeSpan ReadTimeSpan(string key, Action<TimeSpan> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.Action<System.TimeSpan>	validate	An optional callback to validate the value.

Returns

Type	Description
System.TimeSpan	The found TimeSpan value.

Exceptions

Type	Condition
LambdaConfigMissingKeyException	Thrown when no value is found at key.
LambdaConfigBadValueException	Thrown when the value fails validation.

ReadTimeSpan(String, TimeSpan, Action<TimeSpan>)

Read the TimeSpan value for a key at the current path in the hierarchy.

Declaration

public TimeSpan ReadTimeSpan(string key, TimeSpan defaultValue, Action<TimeSpan> validate = null)

Parameters

Type	Name	Description
System.String	key	The name of the value to read.
System.TimeSpan	defaultValue	A value to return if key doesn't exist.
System.Action<System.TimeSpan>	validate	An optional callback to validate the value.

Returns

Type	Description
System.TimeSpan	The found TimeSpan value.

Exceptions

Type	Condition
LambdaConfigBadValueException	Thrown when the value fails validation.

ValidateIsInRange(Int32, Int32)

Creates a callback that validates that a value is in range of the specified lower and upper bounds, inclusively.

Declaration

public static Action<int> ValidateIsInRange(int lowerValue, int upperValue)

Parameters

Type	Name	Description
System.Int32	lowerValue	Lower bound in range.
System.Int32	upperValue	Upper bound in range.

Returns

Type	Description
System.Action<System.Int32>	The validation callback to validate that a value is within the provided lower and upper bounds.

ValidateIsNegative(Int32)

Validates that the value is negative.

Declaration

public static void ValidateIsNegative(int value)

Parameters

Type	Name	Description
System.Int32	value	Value to validate.

Exceptions

Type	Condition
LambdaConfigValidationException	Thrown when the value fails validation.

ValidateIsNonNegative(Int32)

Validates that the value is non-negative.

Declaration

public static void ValidateIsNonNegative(int value)

Parameters

Type	Name	Description
System.Int32	value	Value to validate.

Exceptions

Type	Condition
LambdaConfigValidationException	Thrown when the value fails validation.

ValidateIsNonPositive(Int32)

Validates that the value is non-positive.

Declaration

public static void ValidateIsNonPositive(int value)

Parameters

Type	Name	Description
System.Int32	value	Value to validate.

Exceptions

Type	Condition
LambdaConfigValidationException	Thrown when the value fails validation.

ValidateIsPositive(Int32)

Validates that the value is positive.

Declaration

public static void ValidateIsPositive(int value)

Parameters

Type	Name	Description
System.Int32	value	Value to validate.

Exceptions

Type	Condition
LambdaConfigValidationException	Thrown when the value fails validation.

Extension Methods

AwsConverters.ReadSqsQueueUrl(LambdaConfig, String)

AwsConverters.ReadS3BucketName(LambdaConfig, String)

AwsConverters.ReadLambdaFunctionName(LambdaConfig, String)

AwsConverters.ReadDynamoDBTableName(LambdaConfig, String)