inform-slack

This is a small set of utility scripts (written in bash so that it can run pretty much anywhere) that is intended to make it easier to provide detailed information about things like builds, deployments, and other DevOps-type processes to a Slack Channel.

It works by making one main post in the configured channel that gets updated as the build progresses:

While sending more detailed information about the build into the thread itself:

If you spend your whole day in Slack then getting status updates about builds and deployments there too is great. The problem is that you start out with just something posting a quick "Building thing #123", but then you want to know if it succeeded or failed, and if it failed you want to know why it failed, and if it succeeded you want to know what it actually did, and pretty soon there is so much information in the channel that it becomes much less useful (especially when multiple builds are running at the same time).

This tool uses Slack threads to make this more manageable. Instead of a bunch of messages about everything that is going on, this helps you to organize that information, by having your automated systems post one in-channel message per "process", with more detail in the thread.

When the build is complete you can replace the main message that started the thread with whatever information is useful to know about that build.

It also contains a bunch of helper functions that make it easy to generate rich, detailed information about these processes.

Getting Started

Installing

inform-slack is written in bash to give it minimal dependencies. The only external dependencies are things you likely already have anyway:

• curl
• jq

If you are using basher to manage bash packages, that's the easiest way to install:

basher install jasonk/inform-slack

You can also just clone this repository wherever you need it and then add it's bin directory to your path.

git clone https://github.com/jasonk/inform-slack
export PATH="$(pwd)/inform-slack/bin:$PATH"

Alternately, you can just symlink the main script to somewhere already in your path:

# ln -s ./inform-slack/bin/inform-slack ~/bin/

Configuring

Next you need to setup some environment variables to provide the information needed to build the main message and send it to Slack. For testing purposes you can just do this from the command line, in real usage you would want to provide these using whatever tools your build/deployment pipeline provides for supplying environment variables (or just wrap it all up in a script that can customize it for you).

(See CONFIG.md for more details about configuration).

export INFORM_SLACK_CHANNEL='C12345678'
export INFORM_SLACK_TOKEN='xoxb-not-a-real-token-put-yours-here'
export INFORM_SLACK_TITLE=':construction: Testing a Thing'
export INFORM_SLACK_PROGRESS_MAX=5
export INFORM_SLACK_PROGRESS_POS=0

Initializing

Now, with that configuration setup, you can send an init message to start a thread:

export INFORM_SLACK_THREAD="$(inform-slack --initialize)"

Note that we captured the output of the inform-slack command and re-exported it as $INFORM_SLACK_THREAD. When run with --initialize it both posts the initial message and also captures the ID of the thread that was created, dumping it to stdout to make it easy for you to capture. When run as a command, this is the only thing that inform-slack will print to stdout, because it's required that you capture it and set it in the environment to be available to future commands. This is required to allow those future commands to be able to add messages to the thread.

Sending Messages

Once you have an initialized thread and have it's thread ID in your environment, there are a couple of ways you can call inform-slack.

See demo-script.sh for a complete example showing how this works (it's the script used to generate the messages shown in the demo gif above).

Add a regular old message to the thread

If you just call it with any random string, then that will be added as a message to the thread. If you give it more than one argument this way then they will each be turned into a message (though they will all be sent to Slack as one batch, to help avoid hitting rate limits).

inform-slack "Completed the first part"
# or, more explicitly:
#inform-slack --message "Completed the first part"

You can use Slack emoji and markup in these messages.

Add a complex, structed message with a builder

We use builder scripts to make it easy to post detailed messages about things like test results, build/deployment progress and status, or whatever else you might want to let your teammates on Slack know about.

You can run inform-slack --list-builders to see what builders are available, then run one of them by by using the --attach flag (--builder is an alias if you find that easier to remember).

To post a message with a builder, you just specify the builder name and whatever arguments it might take.

Some examples:

inform-slack --attach tap-summary ./test-data/*.tap
inform-slack --builder junit-summary ./test-data/junit-*.xml
inform-slack --builder checkstyle-summary ./test-data/checkstyle-*.xml

In addition, if you are experimenting with inform-slack by running it on your desktop (or with X-forwarding or something that would allow it to open a browser) you can replace --attach with --preview and inform-slack will run the appropriate builder, but then instead of submitting the message to Slack, it iwll open a browser where you can see how it will look using Slack's Block Kit Builder.

inform-slack --preview tap-summary ./test-data/*.tap

This also lets you see how it will look on both the Desktop and Mobile clients, and with dark or light theme.

See BUILDERS.md for more information about builders.

Update the threads main status message

If the first non-option flag to inform-slack is --update, then it will update the main message (the one that started the thread). You can specify a builder script and it's arguments after --update, or it will use whatever is specified by $INFORM_SLACK_BUILDER, or the default.

This means in a build pipeline, for example, you might use it like this:

if ./deploy-application; then
  INFORM_SLACK_STATUS=":package: Deployed to production!"
else
  INFORM_SLACK_STATUS=":boom: Deployment failed!"
fi
inform-slack --update

Important Note About Security

This tool uses curl to send the actual requests to Slack, but in order to be as safe and secure as possible, we do try to avoid putting your Slack API token as a command line argument where anybody that can run ps can see it. However, the way we do this is by using curls ability to read headers from a file (and we use bash redirection to make it read from a temporary pipe instead, so it never actually gets written to the disk).

However, this curl feature was added in version 7.55, so if you have a version of curl older than that, we fall back to including the Authorization header as a command-line argument. If you are using this on a multi-user machine and you want to ensure that this doesn't happen, you can set $INFORM_SLACK_REQUIRE_HEADER_SAFETY to any non-empty value, and if we detect that your curl version is too old we'll just die instead of falling back.

Author / License

Copyright 2021 - Jason Kohles https://www.jasonkohles.com/ https://github.com/jasonk/

Released under MIT license.