Deploying a Go Slack Bot on Cycle

The Cloud is enabling companies to scale their businesses affordably. But the jump from development to managing containers, deployment, networks and learning all the tools a cloud platform provides can be very challenging. Fortunately, Cycle has come along and made this process incredibly simple. This article will cover how I deployed a Slack bot onto Cycle.

Prerequisites

This article would be too long if I tried to cover everything, so I will be assuming the following:

  • You have a Slack API created. This will be the bot instance of your application and will have all the tokens you need to connect to it. Slack API
  • You have a server set up on Cycle — the steps up to ‘Creating an Environment’, from their getting started guide.
  • You have Docker installed and have an account on Docker Hub

The Code

For interacting with the Slack API, we will be using this package from github. I wrote a very simple Slack bot in Go that you can find here:

  ### Checkout the repository
  ~$ git clone https://github.com/kamiyaa/cycle-projects.git
  ~$ cd cycle-projects/slack-bot

  ### Building
  ~$ go build .

  ### Installing
  ~$ go install .

  ### Running
  ~$ ./slack-bot

To keep our Slack token secret, our container will utilize persistent storage for storing configs. Docker volumes allows us to achieve this and Cycle’s stateful containers allows to easily configure and scale these volumes. More on stateful containers later.

### example bot.toml config file
slack_token = "xox...."
port = 4000
cycle_api_key = "secret_...."
hub_id = "..."

Writing a Dockerfile and Hosting it on Docker Hub

In order to deploy our Docker container to the cloud, we need to write a Dockerfile, build it and push it onto a Docker Registry such as Docker Hub. The Dockerfile for our Slack bot can be found here.

FROM golang:latest
ARG SLACKBOT_HOME=/var/slack_bot
ARG WORK_DIR=/home/builds
ARG BOT_CONFIG=$SLACKBOT_HOME/bot.toml
ENV SLACKBOT_CONFIG $BOT_CONFIG
VOLUME $SLACKBOT_HOME
COPY / $WORK_DIR
RUN cd $WORK_DIR \
 && go install .
ENTRYPOINT [ "./bin/slack-bot" ]

Here, we have a Dockerfile that copies all our source files into /home/builds , then installs it into /bin (default GOPATH). We specify a volume at /var/slack_bot where our config file will reside. The data in this volume will persist even when containers are restarted or reimaged. We specify an environment variable so our bot knows where to find the config file. Finally, we have an entrypoint; the command our container will run when started.

Now we must host our docker image somewhere for Cycle to see. So we will push our image to Docker Hub.

# Build our docker image
~$ docker build -t <dockerhub_username>/<dockerhub_repository> -f Dockerfile .
# push our docker image onto docker hub
~$ docker push <dockerhub_username>/<dockerhub_repository>:latest

Setting Up a Container on Cycle

Head over to your Cycle Dashboard and click the Environment section on the left-hand side to see your Enviroment Dashboard. Create or select the environment for our Slack bot and then deploy a container for it. Environments allow containers inside it to talk to each other through private networks, i.e. a server and a database. So in the future, if we wanted to add more functionality to our Slack bot, we may deploy additional containers to run side-by-side with it.

Environment Dashboard Environment Dashboard deploy containers Create a new container by clicking “Deploy Containers”

Now we want to make sure our container can connect to Slack’s APIs (the public internet) and have persistent storage for our configs. To allow our container to connect to the public internet, simply set Public Network to ‘enabled’. For persistent storage, Cycle’s Stateful containers automatically configures the container for persistent storage. To enable it, set the Stateful option for our container.

deploy wizard 3

In order to put our application onto Cycle, we can import our docker image from Docker Hub by pressing Import New Image. We also have the option to provide Docker Hub credentials for private images.

private registry

Cycle will import and configure our image automatically. We see Cycle was able to detect volumes specified in our Dockerfile and allows us to configure how much space to allocate for the volumes. For this Slack bot, 16MB will be plenty of space.

volume size Cycle automatically detects Volumes and asks us to specify how much storage we need.

Now we must configure our container to behave like a server by opening port 80. This usually requires delving into Docker’s documentation and passing in the correct ports, protocols, etc. Cycle makes these configuring these options effortless through its interface. For example, currently our toml file configures our Slack bot to listen on port 4000. Simply create a port configuration on Cycle that forwards incoming port 80 requests to our container’s port 4000.

port config Easily map ports to container ports on Cycle

Finally, click Create Container and our container has been created!

Managing Volumes via SFTP

Our container has been created, but our Slack bot won’t run without the token stored in our config file. Cycle makes it easy to move files to our volume via SFTP:

  1. Enable Remote Access to our container’s volume.
  2. Set a password and save changes.
  3. Head over to the instances tab and scroll down to ‘Connected Volumes’.
  4. Now we can get information on how to connect and copy files to our volume.

Set a password and save changes, then head over to the instances tab and scroll down to ‘Connected Volumes’ and now we can get information on how to connect and copy files to our volume.

volume config ra Enabling remote access for SFTP

Deploying the Container

Finally, we deploy our Slack bot! Simply go back to our Environment and press the start button.

env dash

Now we can copy our domain url and use it in our Slack slash commands!

container summary Cycle automatically generates a domain for us to use for this container.

Testing

Now we can add a slash command to complete our Slack bot!

bot test return data

Making Changes

Things are constantly changing. We may want to add new features or fix bugs in our Slack bot. Cycle makes re-deployments very straightfoward. To update a container to use our latest Docker images, re-import the image from the Images tab on the sidebar and reimage the container under the settings tab of your container.

container settings Reimage from container settings

Conclusion

We started with our small Slack bot and was able to containerize it, deploy it and easily maintain it thanks to Cycle’s multi-cloud infrastructure management platform. With Cycle’s stateful containers and easy network configurations, its never been simplier to deploy containers to the cloud. I hope this article helped familiarize you more with developing, deploying and maintaining containerized applications on Cycle.

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