HALO Flows

HALO Flows is the event pipeline engine. It is a visual builder for automated responses to network and sensor events. A flow chains triggers, conditions, and actions; the gateway evaluates flows on a background scheduler and inline on incoming telemetry.

How flows run

The scheduler runs every 30 seconds. Heartbeat and telemetry triggers also evaluate inline as data arrives, so threshold breaches act without waiting for the next scheduler tick. Flows are authored graphically on the Flows page of HALO Portal and execute on the gateway.

Triggers

A trigger starts a flow.

Trigger	Fires on
`sensor_value`	A telemetry metric crossing a configured value
`node_event`	A node lifecycle or state event
`schedule`	A time schedule
`manual`	An operator action or `POST /v1/flows/{id}/trigger`

Conditions

A condition gates whether execution continues.

Condition	Effect
`threshold`	Compare a metric against a value with an operator
`cooldown`	Rate-limit a flow to suppress repeat firing
`response`	Parse and test the result of a prior step

Actions

An action does the work.

Action	Effect
`alert`	Raise a platform alert
`webhook_out`	Send an outbound webhook (Teams, Slack)
`command`	Run a command over SSH on a node
`for_each_node`	Iterate an action across nodes

Context variables

Action templates interpolate context variables resolved at execution time.

text

{node_id}    {node_name}    {metric}    {value}
{threshold}  {operator}     {prev_result}

A webhook body or alert message can reference these directly, for example: Node {node_name} {metric} hit {value} (threshold {threshold}).

Data model

Flows persist across a set of SQLite tables on the gateway.

Table	Holds
`flows`	Flow definitions
`flow_steps`	Individual trigger/condition/action steps
`flow_edges`	Connections between steps
`flow_executions`	Execution history
`flow_action_templates`	Reusable action templates
`flow_alerts`	Raised alerts
`flow_variables`	Flow-scoped variables

API

Flows are fully manageable over the API. See the gateway API reference for the full list.

bash

GET    /v1/flows                 # list flows
POST   /v1/flows                 # create a flow
GET    /v1/flows/{id}            # get a flow
PUT    /v1/flows/{id}            # update a flow
DELETE /v1/flows/{id}            # delete a flow
POST   /v1/flows/{id}/trigger    # trigger manually
GET    /v1/flows/{id}/executions # execution history
GET    /v1/flows/metadata        # trigger/condition/action types
GET    /v1/flows/metric-preview  # preview metric values for conditions

Flow execution today follows linear step order. Graph execution with branching — topological edge traversal — is the next planned step for the engine.

Where to go next

Author flows on the Flows page in HALO Portal.
See which metrics are available as triggers in IO and sensors.
Pull third-party data into flows via external systems.