Generic dynamic container component that encapsulates the life-cycle of other components.
Container membership changes at run-time.
We use a supervisor strategy similar to Erlang/OTP one-for-one:
components are assumed to be independent, and if one of them dies we just
restart that component. Order of component shutdown or start is arbitrary.
The child's spec.env can contain a boolean attribute
__ca_temporary__ that disables component restart. This is useful when we
rely on external mechanisms to restart components, as is the case with CAs.
The following required properties specify recovery behavior for non-temporary components:
{ maxRetries: number, retryDelay: number}
where maxRetries is the number of attempts before giving up, and
retryDelay is the delay in msec between attempts.
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Extends
Members
$ :Object.<string, Object>
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A context to register children. We can pass an existing children context in $.$
Type:
- Object.<string, Object>
__ca_isDynamicContainer__ :boolean
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Run-time type information.
Type:
- boolean
Methods
(static) create($, spec) → {Object}
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Helper constructor method for a dynamic container component.
Description of types in file types.js.
Parameters:
| Name | Type | Description |
|---|---|---|
$ |
ctxType | A context containing references to other components. |
spec |
specType | Configuration data for this component. |
Throws:
-
If inputs are invalid.
- Type
- Error
Returns:
A new generic component.
- Type
- Object
__ca_allChildren__() → {Array.<string>}
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Returns an array with the names of all the children that are currently active.
Returns:
The names of all active children.
- Type
- Array.<string>
__ca_deleteChild__(dataopt, childName, cb)
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Deletes and shutdowns a child component.
This is an idempotent operation.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
data |
Object |
<optional> |
An optional hint on how to delete the child. |
childName |
string | A name for the child. |
|
cb |
cbType | A callback to return an error if a child still exists
and |
__ca_getChildSpec__(name) → {specType}
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Returns the spec for a created child.
Parameters:
| Name | Type | Description |
|---|---|---|
name |
string | The name of the child component. |
Returns:
The spec of a running child.
- Type
- specType
__ca_instanceChild__(dataopt, childSpec, cb)
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Adds a new child component if it was not already created.
We avoid race conditions by using a queue to serialize child creation.
There is no guarantee that the returned child used the provided
description, it could have already been created with a different
one. Use __ca_deleteChild__ first to force a description.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
data |
Object |
<optional> |
An optional hint on how to add the child. |
childSpec |
Object | A child description. |
|
cb |
cbType | A callback to return an error or the new (or existing) child. |