Disclaimer : I’m not affiliated with gitlab in anyway, or being compensated from any recommendations I make, in fact this tutorial with minimal tweaking can work with Bitbucket-CI, Travis-CI, Circle-CI and others. If you you want to skip the discussion below and go straight to the instructions, scroll to where it says Let’s get you started. So Google is . cracking down on android apps background services No wonder that the bitcoin app I’m using did not alert me for the recent price dip. There are many scenarios when you want a service to continuously check for a condition, and alert you when this condition is met. something like a webhook. The first definition that pops up when you is: google webhook A is an HTTP callback: an HTTP POST that occurs when something happens; a simple event-notification via HTTP POST. A web application implementing will POST a message to a URL when certain things happen. WebHook WebHooks In the previous tutorial we have tackled . running periodic jobs with gitlab In this very similar tutorial we will add conditions, we will create a webhook: A periodic job will run daily : GET bitcoin price It will check if a condition is met : if the bitcoin price is greater than x and lesser than y If the condition is met it will POST an alert : we will direct this post request to an http request inspector to see it in action, BUT we can also ,with the proper authentication, direct it to another service like IFTTT or Zapier to cause it to trigger 100s of connected services. For example let your smart lights turn green if bitcoin is within a specific price range, or even trigger a song to play. we discuss in details how to connect this same project to IFTTT and have IFTTT alert us with a phone call, email, or tweet when the price of bitcoin reaches a specific range. In another article IFTTT allows you to connect to hundreds of services and smart appliances, l ist of IFTTT services There are many ways for creating webhooks, but this is my favourite way because: It’s easy, this whole tutorial can be completed from a browser, you can use your mobile phone and in 71 seconds you would have a functioning webhook. It can be set up in seconds : I don’t need to set up a server on my own, not even a cloud instance, so I can focus on creating what I need, rather than get tangled in system admin tasks . Although it’s also easy to run a cron job from an always-on always-connected computer or a server, like a Raspberry Pi. This is not practical for everyone, specially travellers and digital nomads. It provides more freedom and versatility : you can obviously use IFTTT to trigger events, IFTTT is very slick with a great API and a nice free tier, but then you’re limited to the integrations IFTTT does and does not provide, also you’re limited by their caps, for example free IFTTT caps your tweets at 100/day, although that’s perfectly fine, you can’t compare that to the actual Twitter cap of 2,400 tweets/day. This can last, with other services you’ll end up getting a bill, either after you pass a certain quota or because it can run as long as gitlab continues to offer 2000 min/month of free build time on shared build runners. this is enough to run our sample code here 16 times per day, this is once every 90 minutes each month. As of this writing Bitbucket on the other hand only offers 50 minutes/month. Bitbucket hosted CI free includes 50 min /month build time 5. Gitlab integrates the code repo with the build system, sure you can host your code on Github and build with Travis or Circle-CI, but I would like to login once and manage both the repo and the build process, and I don’t have to mess around with ssh keys to access another service. 6. Gitlab allows private repos : Travis CI allows free unlimited build minutes for personal projects, but the last I’ve checked Travis-CI only supports free builds for public repos. 7. Gitlab uses containers to allow users to create their build stack, so although for this tutorial we’re using a simple bash file, in reality you can specify a container that tests, builds and deploys your Android app, Java application using Maven or Gradle, Ruby, Node , Python, Django and a long list of applications, better yet Gitlab has ready standard templates to automatically set the build stack for you. I’ve forked . a list of ready templates here So in essence you provide your code, and Gitlab-CI provides the right environment to build your code (you just tweak the YAML file template provided by Gitlab-CI). Here is . the official Gitlab-CI examples page If you are into browser automation, there’s for using Gitlab-CI to automatically spin up a docker container ready with chrome-headless to run Selenium tests. a cool tutorial by Joyz 8. The project build file .gitlab-ci.yml is very similar to the configuration file used in many other services, including Travis-CI, Bitbucket-CI Circle-CI and others, even Jenkins has a YAML file plugin. this makes migration easy if the need arise. 9. Not that we used an open API to retrieve Bitcoin price, this does not mean that we are limited to APIs that does not require private key or token authentication. Like other services you can store private keys as variables in Gitlab-CI, for example MY_API_PRIVATE_KEY , and then use ‘$MY_API_PRIVATE_KEY’ in your .gitlab-ci.yml file to authenticate when calling the API. you can store private keys as variables in Gitlab-CI to authenticate API calls if you do that make sure that you set your build Pipeline toprivate, otherwise other will be able to see your keys in plain text. Let’s get you started: : All levels Level : Any web browser Requirements (or create a new account) at G (10 seconds) Sign in itlab.com 2. Click on button to create a new repo, in the name field type or any other name. (9 seconds) Create a new Project : New Project btc-webhook Then save it By clicking on (1 second) Create Project 3. Click on , copy and paste the following snippet into the file then click save (10 seconds) Create a btc-price-alert.sh file in this new project : New File btc-price-alert.sh #!/bin/bashecho 'request Bitcoin price';x=$(curl ) https://min-api.cryptocompare.com/data/price?fsym=BTC\&tsyms=CAD echo 'removing all non digit from the response'x=${x//[^0-9\.]/} echo 'Bitcoin price is CA$ '"$x" echo 'removing decimals from the price'x=${x%.*} echo 'checking if the price within the defined range' if \[ "$x" -ge 10000 -a "$x" -lt 14000 \]; then echo 'price is within range, will post an alert' curl -i -X POST [https://putsreq.com/wkDdMQWhaOyalisaIe49](https://putsreq.com/wkDdMQWhaOyalisaIe49) --data 'price='"$x" else echo 'Price is not within range, no alert posted this time' fi This will check if the price of bitcoin above CA$ 10,000 and less than CA$ 14,000 . feel free to customize it. 4. (20 seconds) Click on the home menu icon to go back to your project’s home page. Create another file, call it .gitlab-ci.yml file : click on the plus icon next to your project’s name and select New File from the menu copy and paste the following snippet into the .gitlab-ci.yml file then click save test: script: bash btc-price-alert.sh this is a simple commands, to run the bash file that we’ve created Click on the button, this will trigger it to build and run. Commite changes 5. click on the CI/CD icon to expand the menu, select Schedules to set up a name and a timer for your webhook to trigger. (11 seconds) Schedule it to check price everyday : click on button New schedule Type in a name for the new schedule , select to run it daily, or whenever you want it to run, then click daily-bitcoin-price-alert Save Your scheduled job has been saved 6. . if the price within the range you’ve specified, the webhook will post an alert. go to to to see it in action. (10 seconds) Congrats! you’re done this link in putsreq.com This job will run everyday as long as your free 2000/month build minutes do not run out. You can find the and previous read the jobs sample code here build logs here we can still kick it up a notch If still want to integrate your webhook with IFTTT, this can be easily be done This will be the topic of the coming tutorial
