This is a small demo created to have a chance to play around with the APIs exposed by Bandwidth along with a few other bits of technology.
The goal was to get a SpringBoot app up in a Docker container that would let someone send me a message via SMS or make a SIP phone call to me. The constraints were I had to do with equipment I had on-hand, software I could get for free (or very cheaply, i.e. the Bandwidth trial account), and I could only do it in the time I could carve out of a single weekend, starting on a Friday evening and finishing on Sunday.
Software programs/services I used:
- IntelliJ IDE
- Docker Toolbox for Windows
- Chrome (for lots and lots of searches)
- Container Station Docker Manger for QNAP NAS
- GitHub for version control
Primary software frameworks I used:
- Spring Boot / Spring Boot Starter
- Java JDK8
- Thymeleaf
- com.spotify dockerfile-maven-plugin
- com.googlecode.libphonenumber for Directory Number (DN) validation and formatting
- Swagger for API documentation
Hardware used:
- My desktop Windows 10 PC - development and test deployments
- My SurfaceBook 2 - development
- My two QNAP NAS boxes - Docker Station and final Run Environment
- iPhone + BT Speakers + AppleMusic - ambiance
- HDTV + Xbox One + Rogue One: A Star Wars Story - sanity
The Good
The SpringBoot app and its user facing API all work correctly. The user can submit a message and or call request and it is properly received, validated, and responses passed back to the user.
The Docker image is built and runs correctly.
The SMS messagse are correctly sent to my mobile number through the Bandwidth REST API.
All-in-all, for a "weekend sprint", it felt satisfyingly productive.
The Bad
Partly due to the constraints on the trial Bandwidth account regarding calls needing to be SIP-to-SIP and how it did not appear completely clear how to generate a call out to two parties and then bridge them (something that is most likely in the API set but not something I had time to get further into), calling was never implemented past the UI stage.
The Ugly
Despite having the Docker daemon setup with insecure registries and Container Station properly running a self-signed registry, I could never get build Docker images to push from my development machines to the goal Docker environment. I was able to save out the image as a tarball and manually import it into Container Station to get my Docker-ized application running where I wanted it.
Springfox is not properly exposing the Swagger API docs. Not a problem for the demos functionality but annoying at least.
There is some error checking but not a lot of it and the same goes for logging. Both could stand some enhancing. There is no testing to speak of.
Container Station: I was aware the my NAS boxes supported running certain standard VM image formats via the QNAP Visualization Station but had never used it, running all of the 3rd party services I use on my servers as directly installed packages to save on resources. I had not noticed that Container Station was an option until now. I will definitely consider using this to migrate some of them to lighter-weight containers with environment isolation in the future.
Thymeleaf: Doing most of me development in the past on protocols, system services, and back-ends, I had not really done much with UI. Since I needed a form to get user input and did not want to spend the time working through building a JavaScript-based front-end, the ability to define templates and post data back and forth with POJOs that Thymeleaf provided was very nice. I can using this in the future when prototyping back-end services when I want a quick interface to it other than using raw HTTP via cURL or firing up something like Postman/Swagger.
Libphonenumber: It had been a long time since I'd thought about validating phone numbers or converting formats. It was nice to find a library to do some of the heaving lifting without resorting to potentially piles of regex. It is possible this is also availble in the REST API or SDKs that Bandwidth provides and I just did not find it quickly enough.
dockerfile-maven-plugin: I was familiar with using a Maven plugin from io.fabric8 for building a Docker image that had been composed via a Dockerfile spec at work but I went looking to see what other alternatives were out there. I found this plugin from Spotify and it seems pretty capable. The only issue, previously mentioned, was figuring out how to get it to build/push against Container Station directly.
Bandwidth APIs: I hesitate to say I learned a great deal about these. I only scratched the surface of what's available there but I was able to get a little feel for how it worked and would like to revisit it in time now that I have a development base to play with.
Spring Boot Starter: I have used Spring and Spring Boot before but had always started from scratch and/or used some pre-selected base Maven pom files that were the standard at work to pull the working set of dependencies. I tried using the web-based starter this time to pull in what I needed or though I needed to start. It was interesting and to a degree less error prone way to get a bunch of matching dependencies. I could see using it for prototypes and projects like this but I think the manually currated, shared base approach is still likely the best bet for business development by teams.
So what could be tried next?
- Sending a multimedia payload (i.e. MMS)
- Add more comments, logging, error handling.
- Restrict source DNs to be a SIP URI for attempting calls.
- Look into getting calling working potentially leveraging my Ooma Teleo or Astrisk on QNAP.
- Termination to a softphone client on iOS.
How do I set this up to reproduce it?
- Clone the repo and pull it into IntelliJ or your favorite IDE - I will assume you have that installed along with a version of JDK8 or higher.
- Edit the properties file src/main/resources/application.properties
- Add your API Key, User Name, and Password found in the your Bandwidth account dashboard under profile
- Add your Bandwidth DN as the sourceDN
- Add the target you want to send messages (and eventually calls) to in the destDN field.
- Build and run the Spring Boot application (by default it will be on localhost:8090/bandwidth/demo) and verify it works.
- Build and push the Docker image to your docker host
- I am assuming you have your Docker environment setup
- I did this from a Cygwin terminal in the root directory of my workspace:
- mvn package dockerfile:build
- mvn package dockerfile:push
- From there you can create a container in Docker for this image, be sure to expose port 8090 if you want to reach it from outside the Docker world.