Context and Task

Data Context is an object injected into logic functions at runtime, which containes some key components:

• Task and execution-related information
• Trigger payload

Availability

• ✓ Generic logic
• ✓ Aggregator logic

Context

Type:

• GenericContext (generic logic)
• AggregatorContext (aggregator logic)

When a logic gets executed, a data context object ctx will be available in both run and handleError functions:

JavaScript

export async function run(ctx) {
    // ctx is the data context
}

export async function handleError(ctx, error) {
    // the same context as well as error
}

TypeScript

import { GenericContext, RailwayError } from "@fstnetwork/loc-logic-sdk";

export async function run(ctx: GenericContext) {
    // ctx is the data context
}

export async function handleError(ctx: GenericContext, error: RailwayError) {
    // the same context as well as error
}

Railway Error

Type: RailwayError

RailwayError is a object extended from the standard Error class, which will be passed to handleError() upon an error occurred:

export async function handleError(ctx, error) {
    // ...
    const errorMessage = error.message; // error message
    const errorLogicId = error.logicPermanentIdentity; // the PID of the logic that have error occurred
    const errorLogicRevision = error.logicRevision; // the revision of the logic that have error occurred
}

See Tips on Error Handling for details on logic error handling.

Task

Type: Task

export async function run(ctx) {
    const task = ctx.task;
}

A task is an execution of this particular data process invoked by a trigger. The task object is lazy-loaded and would include all related metadata to the logic context:

Member	Type	Description
taskKey	TaskKey, which is { taskId: string, executionId: string }	Task ID and execution ID
taskId (deprecated)	taskId, which is { id: string, executionId: string }	Task ID and execution ID
startTimestamp	Date	Task start datetime
startAt (deprecated)	Date	Task start datetime
dataProcess	VersionedIdentityContext	Data process permanent ID
currentLogic?	VersionedIdentityContext	Current logic permanent ID
executedLogics	Array<VersionedIdentityContext>	An array of identity of executed logic

Versioned Identity Context

Represents the identity of a logic or a data process:

Member	Type	Description
name	string	Name
permanentIdentity	string	Permanent identity string (PID)
revision	number	Revision number

Example

const taskId = ctx.task.taskKey.taskId;
const executionId = ctx.task.taskKey.executionId;

// you can still use the deprecated interfaces:
// const taskId = ctx.task.taskId.id;
// const executionId = ctx.task.taskId.executionId;

const dpPid = ctx.task.dataProcess.permanentIdentity;
const logicPid = ctx.task.currentLogic.permanentIdentity;