Activity-DSL-Linear
The activity-dsl-linear
gem brings:
DSLs strategies for buildig activities. It is build around activity
gem.
Please find the full documentation on the Trailblazer website. [Note that the docs are WIP.]
Example
The activity-dsl-linear
gem provides three default patterns to model processes: Path
, Railway
and FastTrack
. Here's an example of what a railway activity could look like, along with some more complex connections (you can read more about Railway strategy in the docs).
require "trailblazer-activity"
require "trailblazer-activity-dsl-linear"
class Memo::Update < Trailblazer::Activity::Railway
# here goes your business logic
#
def find_model(ctx, id:, **)
ctx[:model] = Memo.find_by(id: id)
end
def validate(ctx, params:, **)
return true if params[:body].is_a?(String) && params[:body].size > 10
ctx[:errors] = "body not long enough"
false
end
def save(ctx, model:, params:, **)
model.update_attributes(params)
end
def log_error(ctx, params:, **)
ctx[:log] = "Some idiot wrote #{params.inspect}"
end
# here comes the DSL describing the layout of the activity
#
step :find_model
step :validate, Output(:failure) => End(:validation_error)
step :save
fail :log_error
end
Visually, this would translate to the following circuit.
You can run the activity by invoking its call
method.
ctx = { id: 1, params: { body: "Awesome!" } }
signal, (ctx, *) = Update.( [ctx, {}] )
pp ctx #=>
{:id=>1,
:params=>{:body=>"Awesome!"},
:model=>#<Memo body=nil>,
:errors=>"body not long enough"}
pp signal #=> #<struct Trailblazer::Activity::End semantic=:validation_error>
With Activity, modeling business processes turns out to be ridiculously simple: You define what should happen and when, and Trailblazer makes sure that it happens.
Features
- Activities can model any process with arbitrary flow and connections.
- Nesting and compositions are allowed and encouraged (via Trailblazer's
dsl-linear
gem). - Different step interfaces, manual processing of DSL options, etc is all possible.
- Steps can be any kind of callable objects.
- Tracing! (via Trailblazer's
developer
gem)
Operation
Trailblazer's Operation
internally uses an activity to model the processes.
Workflow
Activities can be formed into bigger compounds and using workflow, you can build long-running processes such as a moderated blog post or a parcel delivery. Also, you don't have to use the DSL but can use the editor
instead(cool for more complex, long-running flows). Here comes a sample screenshot.
License
© Copyright 2018, Trailblazer GmbH
Licensed under the LGPLv3 license. We also offer a commercial-friendly license.