Node

class constructs.Node(host, scope, id)

Bases: object

Represents the construct node in the scope tree.

Parameters:

Methods

add_dependency(*dependencies)

Add an ordering dependency on another Construct.

All constructs in the dependency’s scope will be deployed before any construct in this construct’s scope.

Parameters:

dependencies (IConstruct)

Return type:

None

add_error(message)

Adds an { “error”: } metadata entry to this construct.

The toolkit will fail synthesis when errors are reported.

Parameters:

message (str) – The error message.

Return type:

None

add_info(message)

Adds a { “info”: } metadata entry to this construct.

The toolkit will display the info message when apps are synthesized.

Parameters:

message (str) – The info message.

Return type:

None

add_metadata(type, data, from_function=None)

Adds a metadata entry to this construct.

Entries are arbitrary values and will also include a stack trace to allow tracing back to the code location for when the entry was added. It can be used, for example, to include source mapping in CloudFormation templates to improve diagnostics.

Parameters:

  • type (str) – a string denoting the type of metadata.

  • data (Any) – the value of the metadata (can be a Token). If null/undefined, metadata will not be added.

  • from_function (Optional[Any]) – a function under which to restrict the metadata entry’s stack trace (defaults to this.addMetadata).

Return type:

None

add_validation(validation)

Adds a validation to this construct.

When node.validate() is called, the validate() method will be called on all validations and all errors will be returned.

Parameters:

validation (IValidation)

Return type:

None

add_warning(message)

Adds a { “warning”: } metadata entry to this construct.

The toolkit will display the warning when an app is synthesized, or fail if run in –strict mode.

Parameters:

message (str) – The warning message.

Return type:

None

apply_aspect(aspect)

Applies the aspect to this Constructs node.

Parameters:

aspect (IAspect)

Return type:

None

find_all(order=None)

Return this construct and all of its children in the given order.

Parameters:

order (Optional[ConstructOrder])

Return type:

List[IConstruct]

find_child(id)

Return a direct child by id.

Throws an error if the child is not found.

Parameters:

id (str) – Identifier of direct child.

Return type:

IConstruct

Returns:

Child with the given id.

prepare()

Invokes “prepare” on all constructs (depth-first, post-order) in the tree under node.

Return type:

None

set_context(key, value)

This can be used to set contextual values.

Context must be set before any children are added, since children may consult context info during construction. If the key already exists, it will be overridden.

Parameters:

  • key (str) – The context key.

  • value (Any) – The context value.

Return type:

None

synthesize(*, outdir, session_context=None, skip_validation=None)

Synthesizes a CloudAssembly from a construct tree.

Parameters:

  • outdir (str) – The output directory into which to synthesize the cloud assembly. Default: - creates a temporary directory

  • session_context (Optional[Mapping[str, Any]]) – Additional context passed into the synthesis session object when construct.synth is called. Default: - no additional context is passed to onSynthesize

  • skip_validation (Optional[bool]) – Whether synthesis should skip the validation phase. Default: false

Return type:

None

try_find_child(id)

Return a direct child by id, or undefined.

Parameters:

id (str) – Identifier of direct child.

Return type:

Optional[IConstruct]

Returns:

the child if found, or undefined

try_get_context(key)

Retrieves a value from tree context.

Context is usually initialized at the root, but can be overridden at any point in the tree.

Parameters:

key (str) – The context key.

Return type:

Any

Returns:

The context value or undefined if there is no context value for thie key.

try_remove_child(child_name)

(experimental) Remove the child with the given name, if present.

Parameters:

child_name (str)

Return type:

bool

Returns:

Whether a child with the given name was deleted.

Stability:

experimental

validate()

Validates tree (depth-first, pre-order) and returns the list of all errors.

An empty list indicates that there are no errors.

Return type:

List[ValidationError]

Attributes

PATH_SEP = '/'
addr

Returns an opaque tree-unique address for this construct.

Addresses are 42 characters hexadecimal strings. They begin with “c8” followed by 40 lowercase hexadecimal characters (0-9a-f).

Addresses are calculated using a SHA-1 of the components of the construct path.

To enable refactorings of construct trees, constructs with the ID Default will be excluded from the calculation. In those cases constructs in the same tree may have the same addreess.

Example:

c83a2846e506bcc5f10682b564084bca2d275709ee
children

All direct children of this construct.

default_child

Returns the child construct that has the id Default or Resource".

This is usually the construct that provides the bulk of the underlying functionality. Useful for modifications of the underlying construct that are not available at the higher levels. Override the defaultChild property.

This should only be used in the cases where the correct default child is not named ‘Resource’ or ‘Default’ as it should be.

If you set this to undefined, the default behavior of finding the child named ‘Resource’ or ‘Default’ will be used.

Returns:

a construct or undefined if there is no default child

Throws:

if there is more than one child

dependencies

Return all dependencies registered on this node or any of its children.

id

The id of this construct within the current scope.

This is a a scope-unique id. To obtain an app-unique id for this construct, use uniqueId.

locked

Returns true if this construct or the scopes in which it is defined are locked.

metadata

An immutable array of metadata objects associated with this construct.

This can be used, for example, to implement support for deprecation notices, source mapping, etc.

path

The full, absolute path of this construct in the tree.

Components are separated by ‘/’.

root

Returns the root of the construct tree.

Returns:

The root of the construct tree.

scope

Returns the scope in which this construct is defined.

The value is undefined at the root of the construct scope tree.

scopes

All parent scopes of this construct.

Returns:

a list of parent scopes. The last element in the list will always be the current construct and the first element will be the root of the tree.

unique_id

(deprecated) A tree-global unique alphanumeric identifier for this construct.

Includes all components of the tree.

Deprecated:

please avoid using this property and use addr to form unique names. This algorithm uses MD5, which is not FIPS-complient and also excludes the identity of the root construct from the calculation.

Stability:

deprecated

Static Methods

classmethod of(construct)

Returns the node associated with a construct.

Parameters:

construct (IConstruct) – the construct.

Return type:

Node