Relations between components

StackState Self-hosted v5.0.x

This page describes StackState version 5.0.

Go to the documentation for the latest StackState release.

Overview

Component and span relations show the relationship between components in StackState. For example, the image below shows a relation running from a parent to a child component, that child also then has another component as a child component:

Service Name: Parent Component
|
---> Service Name: Child Component
     |
     ---> Service Name: Child 2 Component

An example of the above displayed in StackState will show up as follows:

Topology Perspective - Unmerged OTEL Components

These relations are based on the parent and child structure. A relationship is drawn from a parent component to a child component.

This means that:

• Service Name: Child Component has the parent ID set as Service Name: Parent Component

• Service Name: Child 2 Component has the parent ID set as Service Name: Child Component

Health state propagation

In StackState, the health state of a component will propagate upwards through the dependency tree. This means that in the following situation:

Service Name: Parent Component
|
---> Service Name: Child Component [400 Status]
     |
     ---> Service Name: Child 2 Component

The following components will have a propagated CRITICAL state:

Service Name: Parent Component [Propagated 400 Status]
|
---> Service Name: Child Component [400 Status]
     |
     ---> Service Name: Child 2 Component

A visual example of this in the StackState UI will be as follows:

Topology Perspective - OTEL Components CRITICAL State

So remember to create your parent and children spans in the correct order as it may affect the propagation of health state.

➡️ Learn more about health state propagation

Relations when merging

Relations are retained when merging components; this allows you to create a parent component, create a child component for this parent and then merge that child component with an existing component. This will then create a relationship between the pre-existing component that the child component merged with and the parent component. For example, here we have the three components as described above:

Topology Perspective - OTEL Components and Pre-Existing Components

If we then merge our middle component Service Name: Child Component with the existing healthy Lambda component otel-example-custom-instrumentation-dev-create-custom-component in the bottom right corner:

• The middle component will disappear (merged with the Lambda component)

• The Lambda component will have relations to the first and third components (inherited relation mappings from the middle component).

Topology Perspective - Merged with Healthy Component

Multiple children

It is also good to know that a single parent can have multiple children. This allows you to build a tree with branches of relations, for example:

Service Name: Parent Component
|
---> Service Name: Child Component
|
---> Service Name: Child 2 Component

Topology Perspective - OTEL Components with Multiple Children