Service Tree

This guide will demonstrate how services are structured into a tree of routes.

Trunk Plugins and Error Handlers

Some plugins like logging are often best at the root of your service. If you call trunk.use(handler) you can add plugins at the service root so that all requests into the service pass through these plugins. You can also call trunk.cope(handler) to add error handlers to the service root.

Lets create a quick example using serviceberry-logger.

• Create a folder named todos
• In todos/ run the following commands:
  • npm init --yes to initialize a package.json file
  • npm install serviceberry to install Serviceberry
  • npm install serviceberry-logger to install serviceberry-logger
• Create a new file todos/service.js and save the JavaScript below as its contents.

const {createTrunk} = require("serviceberry"),
    logger = require("serviceberry-logger"),
    trunk = createTrunk();

trunk.use(logger())
    .on("*", request => request.getId());

Run node service in todos/ to start your service then visit http://localhost:3000. Your service should respond with the request id. The request will be logged in todos/logs/server.log.

Next we'll add an error handler on the trunk and introduce a bug so we can see the resulting error logged. For the error handler we'll use the error handler provided by serviceberry-logger.

todos/service.js should now look like this:

const {createTrunk} = require("serviceberry"),
    logger = require("serviceberry-logger"),
    trunk = createTrunk();

trunk.use(logger())
    .cope(logger.error)
    .on("*", request => request.getIdd());

Run node service in todos/ to start your service then visit http://localhost:3000. Your service should respond with the error. The request and the error will be logged in todos/logs/server.log.