derhuerst/hafas-generate-gtfs

persistent queue

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#1 opened on Mar 21, 2020

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enhancementhelp wanted

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Description

A persisting queue will allow the script to fail and/or be cancelled, and resumed later. It will also make hafas-generate-gtfs work in memory-constrained environments, or with very large areas.

Changes necessary:

  1. Specify all tasks (departures fetching, trips fetching) in a JSON-serialisable format. (['fetch-trip', tripId, lineName], etc).
  2. Implement an in-memory store for stops, lines & trips (see API below).
  3. Switch from queue to a persisting one. (I'd like to try bullmq.) Also mention in the readme that Redis is required.

store API

{
	hasStop: async id => Boolean,
	getStop: async id => Stop,
	putStop: async (id, stop) => {},
	// same with lines & trips
}

Contributor guide

Research direction
Examine the current queue implementation and replace it with a persistent one using bullmq. Implement the in memory store API for stops, lines, and trips.
Tech stack
javascriptnodejsredis
Domain
backenddata
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Node.jsRedis
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65