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# Trapperkeeper Quick Start
## Lein Template
A Leiningen template is available that shows a suggested project structure:
lein new trapperkeeper my.namespace/myproject
Once you've created a project from the template, you can run it via the lein alias:
lein tk
Note that the template is not intended to suggest a specific namespace organization; it's just intended to show you how to write a service, a web service, and tests for each.
## Hello World
Here's a "hello world" example for getting started with Trapperkeeper.
First, you need to define one or more services:
```clj
(ns hello
(:require [puppetlabs.trapperkeeper.core :refer [defservice]]))
;; A protocol that defines what functions our service will provide
(defprotocol HelloService
(hello [this])
(defservice hello-service
HelloService
;; dependencies: none for this service
[]
;; optional lifecycle functions that we can implement if we choose
(init [this context]
(println "Hello service initializing!")
context)
;; implement our protocol functions
(hello [this] (println "Hello there!")))
(defservice hello-consumer-service
;; no protocol required since this service doesn't export any functions.
;; express a dependency on the `hello` function from the `HelloService`.
[[:HelloService hello]]
(init [this context]
(println "Hello consumer initializing; hello service says:")
;; call the function from the `hello-service`!
(hello)
context))
```
Then, you need to define a Trapperkeeper bootstrap configuration file, which simply lists the services that you want to load at startup. This file should be named `bootstrap.cfg` and should be located at the root of your classpath (a good spot for it would be in your `resources` directory).
```clj
hello/hello-consumer-service
hello/hello-service
```
Lastly, set Trapperkeeper to be your `:main` in your Leiningen project file:
```clj
:main puppetlabs.trapperkeeper.main
```
And now you should be able to run the app via `lein run --config ...`. This example doesn't do much; for a more interesting example that shows how you can use Trapperkeeper to create a web application, check out the [Example Web Service](https://github.com/puppetlabs/trapperkeeper-webserver-jetty9/tree/master/examples/ring_app) included in the Trapperkeeper webserver service project. To get started defining your own services in Trapperkeeper, head to the [Defining Services](Defining-Services.md) page.
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