Nomadsl is a Ruby DSL for generating Nomad job specification files.
Methods mapping to keys and attributes described in the Nomad Job Specification are defined in an includable module.
Nomadsl supports Nomad configuration syntax through version 0.12.0. The mapping of key and attribute names to method names is generally one-to-one, but you can specify arbitrary configuration values to be rendered if necessary.
Simply require 'nomadsl/dsl and the DSL methods will be injected into the
root namespace. For example, this source file:
#!/usr/bin/env ruby
require 'nomadsl/dsl'
job "example" do
type "batch"
region "iad"
datacenters "prod"
parameterized(payload: "required")
group "work" do
task "work" do
vault(policies: ["example-job"])
meta(aws_region: "ap-southeast-2")
dispatch_payload(file: "message.txt")
preloaded_vault_aws_creds("iam", "iam/sts/example-iam")
artifact(source: "s3.amazonaws.com/example-bucket/example-job/script.sh")
config(command: "script.sh")
end
end
end
Will generate this output:
$ ruby example.nomadsl
job "example" {
type = "batch"
region = "iad"
datacenters = ["prod"]
parameterized {
payload = "required"
}
group "work" {
task "work" {
driver = "exec"
vault {
policies = ["example-job"]
}
meta {
aws_region = "ap-southeast-2"
}
dispatch_payload {
file = "message.txt"
}
template {
destination = "secrets/iam.env"
data = <<BLOB
{{with secret "iam/sts/example-iam"}}
AWS_ACCESS_KEY_ID={{.Data.access_key}}
AWS_SECRET_ACCESS_KEY={{.Data.secret_key}}
AWS_SESSION_TOKEN={{.Data.security_token}}
{{end}}
BLOB
env = true
}
artifact {
source = "s3.amazonaws.com/example-bucket/example-job/script.sh"
}
config {
command = "script.sh"
}
}
}
}
You can also set your shbang line to use nomadsl as the interpreter of the
script. This will evaluate everything as Ruby, but with the necessary nomadsl
boilerplate already built in:
#!/usr/bin/env nomadsl
job "nomadsl-example" do
# ...
end
If the file is then marked as executable, you can simply run it to generate the corresponding Nomad job specification.
By requiring only nomadsl, you can inject these methods into another class:
#!/usr/bin/env ruby
require 'nomadsl'
class Example
include Nomadsl
def generate
@result = job "example" do
# ...
end
end
end
puts Example.new.generate
- Make subkeys embeddable in arglists if sensible
- Allow injecting comments into the rendered file
- Finish custom config blocks for each task driver
- Make errors report their correct location
I'm happy to accept suggestions, bug reports, and pull requests through Github.
This software is public domain. No rights are reserved. See LICENSE for more information.