LD sample project to demonstrate some capabilities, complete the assignment, and have some fun.
I chose the following framework and tools for this application primarily because they can get you started in just a few minutes.
- I did the work on a mac and using
brew
to installjava 21
andgradle
- I used IntelliJ as an IDE but, of course, you can use whatever you like
- Spring Boot Initalizr is so great to just download and go so that's what I did
- I picked
vue.js
as the front end because it can be run directly in the browser (without transpiler) and is enough to get this work done - The data and authentication are both in-memory implementations for simplicity
- The default output from the
ldcli
is a string and I use iTerm2 so I pipe the results throughjq
to format the output - I apologize ahead of time for the keys and passwords pushed to git (gulp)
I built a simple application that displays Olympic Medal data. Since the Olympics are super relevant at the moment, customers are clicking more and more on the table. We've heard complaints of slowness. We believe the slowness is due to the size of the table so server side pagination will help.
We used LaunchDarkly to enable a new table that is paginated. We hope to improve the user experience and reduce load on the database.
The application is secured using a very basic framework. These are the users that are configured for each scenario. When using the application, use the logins below when evaluating different scenarios.
Login Name | Password | Groups | Senario |
---|---|---|---|
jojo | gold | USER | Part 1 |
samone | gold | USER,QA_TESTER | Part 2 |
skeet | gold | USER | Part 2 |
surfer | gold | USER,QA_TESTER | Part 2 |
slater | gold | USER | Experiment |
lee | gold | USER | Experiment |
The application should be started from a command line prompt. The following will detail how to get setup and start the app.
These are the configuration steps required to get the application working.
I'm assuming you have access to a modern shell. I used zsh
which is the default on a mac.
Make sure java and gradle are installed. I'm also assuming you know the basics of gradle
.
brew update && brew upgrade
brew install java@21
brew install gradle
brew install jq
brew tap launchdarkly/homebrew-tap
brew install ldcli
Clone the repo and change directories to it. I'll assume you know what you are doing, so I'll ignore directory names, etc.
git clone https://github.com/jonnio/launchdarkly-homework.git
cd launchdarkly-homework
The application needs at least Java 21
so make sure you either have it setup by running
./gradlew --version
and verifying that the output is similar to this with at least Java 21.
------------------------------------------------------------
Gradle 8.8
------------------------------------------------------------
Build time: 2024-05-31 21:46:56 UTC
Revision: 4bd1b3d3fc3f31db5a26eecb416a165b8cc36082
Kotlin: 1.9.22
Groovy: 3.0.21
Ant: Apache Ant(TM) version 1.10.13 compiled on January 4 2023
JVM: 21.0.4 (Homebrew 21.0.4)
OS: Mac OS X 14.5 x86_64
If you have the incorrect version of java, you've installed the correct version using brew, and have
created the symlink (per brew instructions), export JAVA_HOME=`/usr/libexec/java_home -v 21`
will usually get you
to the right place. Gradle will respect your JAVA_HOME
environment variable.
Build and start the application from the command line. It is a Spring Boot app so we can easily start it using the gradle plugin that is already configured.
./gradlew clean bootRun
Navigate to http://localhost:8080/ to login.
Click the Logout
link in the upper right of the menu to logout of the application and change users.
- I used only the
proudction
environment per the instructions - I did the configuration manually on the webpage but did experiment with doing it from a shell script
- Testing automation should be enabled
- I did not have time to set up a
cypress
test suite for testing automation
The technical exercises will require logging in as different users. It will also require the use of the ldcli
to
turn a flag on and off. Configure the ldcli
using the command line:
ldcli config --set access-token api-c66f6280-cda1-4149-9c44-6db333b9ac15
The token presented here will be removed after the evaluation period.
The feature flag used here can be queried with the CLI (pipe to jq
for formatting in iTerm2
):
ldcli flags get --project default --env production --flag feature-olympic-pagination | jq
- Make sure the flag
feature-olympic-pagination
is disabled - Login to the application using the user
samone
. The user will be presented with a table of medals that has scrolling but no pagination. A user can simply sort by a column and scroll. - Enable the pagination feature and note that the screen updates with a pageable table interface.
ldcli flags --project default --environment production --flag feature-olympic-pagination toggle-on |jq -r '{name, kind, key, on: .environments.production.on}'
- Disable pagination by turning the flag off
ldcli flags --project default --environment production --flag feature-olympic-pagination toggle-off |jq -r '{name, kind, key, on: .environments.production.on}'
- Checkout the code for the client listener on line 185 in index.html
- Checkout the code for the server listener on line 30 in LaunchDarklyConfiguration.java. The server listener simply logs the event.
Utilize the individual and rule based targeting by logging in as individual people. Make sure the flag is enabled:
ldcli flags --project default --environment production --flag feature-olympic-pagination toggle-on |jq -r '{name, kind, key, on: .environments.production.on}'
The user jojo
will not have pagination. A target is configured so the user skeet
does have pagination.
- Login as
jojo
and see that the pagination is not available - Login as
skeet
and see that pagination is enabled
A rule is configured such that any user with the role QA_TESTER
will have pagination enabled.
- Login as
surfer
orsamone
to see the pagination (logout) - Login as
jojo
to see that pagination is not enabled (logout)
I've added an experiment that tracks the clicks on the pagination buttons. The experiment uses a css filter to
track clicks on the buttons. Some sample results are in this screen shot:
I created an integration between LaunchDarkly
and my GCP
account via pub/sub
to store the events for
future analytics and reporting. (screenshot pending enablement of integrations)