up(1) is a batching, parallel task-runner.
It's designed primarily to deploy servers, where you can think of up(1) as a
partial replacement for Kubernetes, Nomad, Docker Swarm, and other deployment
tools. Unlike those other tools, up is extremely small, simple, and as a
result, more reliable and less prone to bugs.
up(1) is deliberately similar to make(1) in its config syntax. It differs primarily in its ability to run tasks in batches and prompt before continuing, a small but important difference which enables up(1) to handle zero-downtime, blue-green, rolling deploys.
$ go get -u egt.run/up/cmd/up
Like make(1), up(1) can be used to deploy anything.
You'll describe your server architecture in a single file (Upfile(5)), then
use the up command to bring everything online.
Each Upfile contains one or more commands. All commands run locally, so remote
commands can be executed using something like ssh user@$server "echo 'hi'"
Variable substitution exists, and variables are identified by a $. Variables
can represent a single thing, such as $remote representing my_user@$server
or they can represent a series of commands, such as $provision representing
10 different commands to run. You'll define these commands yourself.
Up gives you access to a reserved, always-available variable in your commands:
$server represents the IP address in the inventory that up is currently
executing commands on.
You can also use environment variables, like the following:
USER=dev up -t 100.0.0.1 deploy
You can access that variable in your Upfile using $USER.
Running commands on the remote host is as simple as using whatever shell you've configured for your local system. See the below example Upfile designed for bash, which runs remote commands using ssh:
remote=$UP_USER@$server
deploy:
# Your steps to compile and copy files to the remote server go here.
# If any of the following lines have non-zero exits, up immediately
# exits with status code 1.
go build -o myserver git.sr.ht/~example/myserver
rsync -chazP myserver $remote:
rm myserver
ssh $remote 'sudo service myserver restart'
sleep 10 && $check_health
update:
ssh $remote 'sudo apt -y update && sudo apt -y upgrade'
ssh $remote 'sudo snap refresh'
Using the example Upfile above, here's how we could deploy to staging:
up -t 100.0.0.1 deploy
Since up does these tasks by running arbitrary shell commands defined in your
project-level Upfile, up works out-of-the-box with:
If we want to deploy to staging and production, we'd write:
up -t 100.0.0.1,100.0.0.2 deploy
To update all of our debian servers, 2 at a time, and exit immediately if any fail, we can run:
up -t 100.0.0.1,100.0.0.2 -n 2 update
Run up -h for additional usage info.
Often in systems you'll have services deployed to dynamic IP addresses, so you won't want to hardcode IPs in your deployment scripts. You can use a service discovery mechanism to pass IPs to up and dynamically look up services by name.
For instance, using inv2ips (which outputs a comma-separated list of IP addresses) with an inventory.json file:
{
"100.0.0.1": ["production", "app"],
"100.0.0.2": ["production", "database"],
"100.0.0.3": ["staging", "app"]
}
We can run our deploy task on all production servers like so:
up -t $(inv2ips production) deploy
# equivalent to: up -t 100.0.0.1,100.0.0.2 deploy
Like any good UNIX tool, up aims to do one thing and do it well. The
following features are out of the scope of up: