README.md
# AASM - Ruby state machines
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## Index
- [Upgrade from version 3 to 4](#upgrade-from-version-3-to-4)
- [Usage](#usage)
- [Callbacks](#callbacks)
- [Lifecycle](#lifecycle)
- [The current event triggered](#the-current-event-triggered)
- [Guards](#guards)
- [Transitions](#transitions)
- [Multiple state machines per class](#multiple-state-machines-per-class)
- [Handling naming conflicts between multiple state machines](#handling-naming-conflicts-between-multiple-state-machines)
- [Binding event](#binding-event)
- [Auto-generated Status Constants](#auto-generated-status-constants)
- [Extending AASM](#extending-aasm)
- [ActiveRecord](#activerecord)
- [Bang events](#bang-events)
- [Timestamps](#timestamps)
- [ActiveRecord enums](#activerecord-enums)
- [Sequel](#sequel)
- [Dynamoid](#dynamoid)
- [Mongoid](#mongoid)
- [Nobrainer](#nobrainer)
- [Redis](#redis)
- [Automatic Scopes](#automatic-scopes)
- [Transaction support](#transaction-support)
- [Pessimistic Locking](#pessimistic-locking)
- [Column name & migration](#column-name--migration)
- [Log State Changes](#log-state-changes)
- [Inspection](#inspection)
- [Warning output](#warning-output)
- [RubyMotion support](#rubymotion-support)
- [Testing](#testing)
- [RSpec](#rspec)
- [Minitest](#minitest)
- [Assertions](#assertions)
- [Expectations](#expectations)
- [Installation](#installation)
- [Manually from RubyGems.org](#manually-from-rubygemsorg)
- [Bundler](#or-if-you-are-using-bundler)
- [Building your own gems](#building-your-own-gems)
- [Generators](#generators)
- [Test suite with Docker](#docker)
- [Latest changes](#latest-changes)
- [Questions?](#questions)
- [Maintainers](#maintainers)
- [Contributing](CONTRIBUTING.md)
- [Warranty](#warranty)
- [License](#license)
This package contains AASM, a library for adding finite state machines to Ruby classes.
AASM started as the *acts_as_state_machine* plugin but has evolved into a more generic library
that no longer targets only ActiveRecord models. It currently provides adapters for many
ORMs but it can be used for any Ruby class, no matter what parent class it has (if any).
## Upgrade from version 3 to 4
Take a look at the [README_FROM_VERSION_3_TO_4](https://github.com/aasm/aasm/blob/master/README_FROM_VERSION_3_TO_4.md) for details how to switch from version 3.x to 4.0 of _AASM_.
## Usage
Adding a state machine is as simple as including the AASM module and start defining
**states** and **events** together with their **transitions**:
```ruby
class Job
include AASM
aasm do
state :sleeping, initial: true
state :running, :cleaning
event :run do
transitions from: :sleeping, to: :running
end
event :clean do
transitions from: :running, to: :cleaning
end
event :sleep do
transitions from: [:running, :cleaning], to: :sleeping
end
end
end
```
This provides you with a couple of public methods for instances of the class `Job`:
```ruby
job = Job.new
job.sleeping? # => true
job.may_run? # => true
job.run
job.running? # => true
job.sleeping? # => false
job.may_run? # => false
job.run # => raises AASM::InvalidTransition
```
If you don't like exceptions and prefer a simple `true` or `false` as response, tell
AASM not to be *whiny*:
```ruby
class Job
...
aasm whiny_transitions: false do
...
end
end
job.running? # => true
job.may_run? # => false
job.run # => false
```
When firing an event, you can pass a block to the method, it will be called only if
the transition succeeds :
```ruby
job.run do
job.user.notify_job_ran # Will be called if job.may_run? is true
end
```
### Callbacks
You can define a number of callbacks for your events, transitions and states. These methods, Procs or classes will be
called when certain criteria are met, like entering a particular state:
```ruby
class Job
include AASM
aasm do
state :sleeping, initial: true, before_enter: :do_something
state :running, before_enter: Proc.new { do_something && notify_somebody }
state :finished
after_all_transitions :log_status_change
event :run, after: :notify_somebody do
before do
log('Preparing to run')
end
transitions from: :sleeping, to: :running, after: Proc.new {|*args| set_process(*args) }
transitions from: :running, to: :finished, after: LogRunTime
end
event :sleep do
after do
...
end
error do |e|
...
end
transitions from: :running, to: :sleeping
end
end
def log_status_change
puts "changing from #{aasm.from_state} to #{aasm.to_state} (event: #{aasm.current_event})"
end
def set_process(name)
...
end
def do_something
...
end
def notify_somebody
...
end
end
class LogRunTime
def call
log "Job was running for X seconds"
end
end
```
In this case `do_something` is called before actually entering the state `sleeping`,
while `notify_somebody` is called after the transition `run` (from `sleeping` to `running`)
is finished.
AASM will also initialize `LogRunTime` and run the `call` method for you after the transition from `running` to `finished` in the example above. You can pass arguments to the class by defining an initialize method on it, like this:
Note that Procs are executed in the context of a record, it means that you don't need to expect the record as an argument, just call the methods you need.
```ruby
class LogRunTime
# optional args parameter can be omitted, but if you define initialize
# you must accept the model instance as the first parameter to it.
def initialize(job, args = {})
@job = job
end
def call
log "Job was running for #{@job.run_time} seconds"
end
end
```
#### Parameters
You can pass parameters to events:
```ruby
job = Job.new
job.run(:defragmentation)
```
All guards and after callbacks will receive these parameters. In this case `set_process` would be called with
`:defragmentation` argument.
If the first argument to the event is a state (e.g. `:running` or `:finished`), the first argument is consumed and
the state machine will attempt to transition to that state. Add comma separated parameter for guards and callbacks
```ruby
job = Job.new
job.run(:running, :defragmentation)
```
In this case `set_process` won't be called, job will transition to running state and callback will receive
`:defragmentation` as parameter
#### Error Handling
In case of an error during the event processing the error is rescued and passed to `:error`
callback, which can handle it or re-raise it for further propagation.
Also, you can define a method that will be called if any event fails:
```ruby
def aasm_event_failed(event_name, old_state_name)
# use custom exception/messages, report metrics, etc
end
```
During the transition's `:after` callback (and reliably only then, or in the global
`after_all_transitions` callback) you can access the originating state (the from-state)
and the target state (the to state), like this:
```ruby
def set_process(name)
logger.info "from #{aasm.from_state} to #{aasm.to_state}"
end
```
#### Lifecycle
Here you can see a list of all possible callbacks, together with their order of calling:
```ruby
begin
event before_all_events
event before
event guards
transition guards
old_state before_exit
old_state exit
after_all_transitions
transition after
new_state before_enter
new_state enter
...update state...
event before_success # if persist successful
transition success # if persist successful, database update not guaranteed
event success # if persist successful, database update not guaranteed
old_state after_exit
new_state after_enter
event after
event after_all_events
rescue
event error
event error_on_all_events
ensure
event ensure
event ensure_on_all_events
end
```
Use event's `after_commit` callback if it should be fired after database update.
#### The current event triggered
While running the callbacks you can easily retrieve the name of the event triggered
by using `aasm.current_event`:
```ruby
# taken the example callback from above
def do_something
puts "triggered #{aasm.current_event}"
end
```
and then
```ruby
job = Job.new
# without bang
job.sleep # => triggered :sleep
# with bang
job.sleep! # => triggered :sleep!
```
### Guards
Let's assume you want to allow particular transitions only if a defined condition is
given. For this you can set up a guard per transition, which will run before actually
running the transition. If the guard returns `false` the transition will be
denied (raising `AASM::InvalidTransition`):
```ruby
class Cleaner
include AASM
aasm do
state :idle, initial: true
state :cleaning
event :clean do
transitions from: :idle, to: :cleaning, guard: :cleaning_needed?
end
event :clean_if_needed do
transitions from: :idle, to: :cleaning do
guard do
cleaning_needed?
end
end
transitions from: :idle, to: :idle
end
event :clean_if_dirty do
transitions from: :idle, to: :cleaning, guard: :if_dirty?
end
end
def cleaning_needed?
false
end
def if_dirty?(status)
status == :dirty
end
end
job = Cleaner.new
job.may_clean? # => false
job.clean # => raises AASM::InvalidTransition
job.may_clean_if_needed? # => true
job.clean_if_needed! # idle
job.clean_if_dirty(:clean) # => raises AASM::InvalidTransition
job.clean_if_dirty(:dirty) # => true
```
You can even provide a number of guards, which all have to succeed to proceed
```ruby
def walked_the_dog?; ...; end
event :sleep do
transitions from: :running, to: :sleeping, guards: [:cleaning_needed?, :walked_the_dog?]
end
```
If you want to provide guards for all transitions within an event, you can use event guards
```ruby
event :sleep, guards: [:walked_the_dog?] do
transitions from: :running, to: :sleeping, guards: [:cleaning_needed?]
transitions from: :cleaning, to: :sleeping
end
```
If you prefer a more Ruby-like guard syntax, you can use `if` and `unless` as well:
```ruby
event :clean do
transitions from: :running, to: :cleaning, if: :cleaning_needed?
end
event :sleep do
transitions from: :running, to: :sleeping, unless: :cleaning_needed?
end
end
```
You can invoke a Class instead of a method if the Class responds to `call`
```ruby
event :sleep do
transitions from: :running, to: :sleeping, guards: Dog
end
```
```ruby
class Dog
def call
cleaning_needed? && walked?
end
...
end
```
### Transitions
In the event of having multiple transitions for an event, the first transition that successfully completes will stop other transitions in the same event from being processed.
```ruby
require 'aasm'
class Job
include AASM
aasm do
state :stage1, initial: true
state :stage2
state :stage3
state :completed
event :stage1_completed do
transitions from: :stage1, to: :stage3, guard: :stage2_completed?
transitions from: :stage1, to: :stage2
end
end
def stage2_completed?
true
end
end
job = Job.new
job.stage1_completed
job.aasm.current_state # stage3
```
You can define transition from any defined state by omitting `from`:
```ruby
event :abort do
transitions to: :aborted
end
```
### Display name for state
You can define display name for state using :display option
```ruby
class Job
include AASM
aasm do
state :stage1, initial: true, display: 'First Stage'
state :stage2
state :stage3
end
end
job = Job.new
job.aasm.human_state
```
### Multiple state machines per class
Multiple state machines per class are supported. Be aware though that _AASM_ has been
built with one state machine per class in mind. Nonetheless, here's how to do it (see below). Please note that you will need to specify database columns for where your pertinent states will be stored - we have specified two columns `move_state` and `work_state` in the example below. See the [Column name & migration](https://github.com/aasm/aasm#column-name--migration) section for further info.
```ruby
class SimpleMultipleExample
include AASM
aasm(:move, column: 'move_state') do
state :standing, initial: true
state :walking
state :running
event :walk do
transitions from: :standing, to: :walking
end
event :run do
transitions from: [:standing, :walking], to: :running
end
event :hold do
transitions from: [:walking, :running], to: :standing
end
end
aasm(:work, column: 'work_state') do
state :sleeping, initial: true
state :processing
event :start do
transitions from: :sleeping, to: :processing
end
event :stop do
transitions from: :processing, to: :sleeping
end
end
end
simple = SimpleMultipleExample.new
simple.aasm(:move).current_state
# => :standing
simple.aasm(:work).current_state
# => :sleeping
simple.start
simple.aasm(:move).current_state
# => :standing
simple.aasm(:work).current_state
# => :processing
```
#### Handling naming conflicts between multiple state machines
_AASM_ doesn't prohibit to define the same event in more than one state
machine. If no namespace is provided, the latest definition "wins" and
overrides previous definitions. Nonetheless, a warning is issued:
`SimpleMultipleExample: overriding method 'run'!`.
Alternatively, you can provide a namespace for each state machine:
```ruby
class NamespacedMultipleExample
include AASM
aasm(:status) do
state :unapproved, initial: true
state :approved
event :approve do
transitions from: :unapproved, to: :approved
end
event :unapprove do
transitions from: :approved, to: :unapproved
end
end
aasm(:review_status, namespace: :review) do
state :unapproved, initial: true
state :approved
event :approve do
transitions from: :unapproved, to: :approved
end
event :unapprove do
transitions from: :approved, to: :unapproved
end
end
end
namespaced = NamespacedMultipleExample.new
namespaced.aasm(:status).current_state
# => :unapproved
namespaced.aasm(:review_status).current_state
# => :unapproved
namespaced.approve_review
namespaced.aasm(:review_status).current_state
# => :approved
```
All _AASM_ class- and instance-level `aasm` methods accept a state machine selector.
So, for example, to use inspection on a class level, you have to use
```ruby
SimpleMultipleExample.aasm(:move).states.map(&:name)
# => [:standing, :walking, :running]
```
### Binding event
Allow an event to be bound to another
```ruby
class Example
include AASM
aasm(:work) do
state :sleeping, initial: true
state :processing
event :start do
transitions from: :sleeping, to: :processing
end
event :stop do
transitions from: :processing, to: :sleeping
end
end
aasm(:question) do
state :answered, initial: true
state :asked
event :ask, binding_event: :start do
transitions from: :answered, to: :asked
end
event :answer, binding_event: :stop do
transitions from: :asked, to: :answered
end
end
end
example = Example.new
example.aasm(:work).current_state #=> :sleeping
example.aasm(:question).current_state #=> :answered
example.ask
example.aasm(:work).current_state #=> :processing
example.aasm(:question).current_state #=> :asked
```
### Auto-generated Status Constants
AASM automatically [generates constants](https://github.com/aasm/aasm/pull/60)
for each status so you don't have to explicitly define them.
```ruby
class Foo
include AASM
aasm do
state :initialized
state :calculated
state :finalized
end
end
> Foo::STATE_INITIALIZED
#=> :initialized
> Foo::STATE_CALCULATED
#=> :calculated
```
### Extending AASM
AASM allows you to easily extend `AASM::Base` for your own application purposes.
Let's suppose we have common logic across many AASM models. We can embody this logic in a sub-class of `AASM::Base`.
```ruby
class CustomAASMBase < AASM::Base
# A custom transition that we want available across many AASM models.
def count_transitions!
klass.class_eval do
aasm with_klass: CustomAASMBase do
after_all_transitions :increment_transition_count
end
end
end
# A custom annotation that we want available across many AASM models.
def requires_guards!
klass.class_eval do
attr_reader :authorizable_called,
:transition_count,
:fillable_called
def authorizable?
@authorizable_called = true
end
def fillable?
@fillable_called = true
end
def increment_transition_count
@transition_count ||= 0
@transition_count += 1
end
end
end
end
```
When we declare our model that has an AASM state machine, we simply declare the AASM block with a `:with_klass` key to our own class.
```ruby
class SimpleCustomExample
include AASM
# Let's build an AASM state machine with our custom class.
aasm with_klass: CustomAASMBase do
requires_guards!
count_transitions!
state :initialised, initial: true
state :filled_out
state :authorised
event :fill_out do
transitions from: :initialised, to: :filled_out, guard: :fillable?
end
event :authorise do
transitions from: :filled_out, to: :authorised, guard: :authorizable?
end
end
end
```
### ActiveRecord
AASM comes with support for ActiveRecord and allows automatic persisting of the object's
state in the database.
Add `gem 'after_commit_everywhere', '~> 1.0'` to your Gemfile.
```ruby
class Job < ActiveRecord::Base
include AASM
aasm do # default column: aasm_state
state :sleeping, initial: true
state :running
event :run do
transitions from: :sleeping, to: :running
end
event :sleep do
transitions from: :running, to: :sleeping
end
end
end
```
### Bang events
You can tell AASM to auto-save the object or leave it unsaved
```ruby
job = Job.new
job.run # not saved
job.run! # saved
# or
job.aasm.fire(:run) # not saved
job.aasm.fire!(:run) # saved
```
Saving includes running all validations on the `Job` class. If
`whiny_persistence` flag is set to `true`, exception is raised in case of
failure. If `whiny_persistence` flag is set to `false`, methods with a bang return
`true` if the state transition is successful or `false` if an error occurs.
If you want make sure the state gets saved without running validations (and
thereby maybe persisting an invalid object state), simply tell AASM to skip the
validations. Be aware that when skipping validations, only the state column will
be updated in the database (just like ActiveRecord `update_column` is working).
```ruby
class Job < ActiveRecord::Base
include AASM
aasm skip_validation_on_save: true do
state :sleeping, initial: true
state :running
event :run do
transitions from: :sleeping, to: :running
end
event :sleep do
transitions from: :running, to: :sleeping
end
end
end
```
Also, you can skip the validation at instance level with `some_event_name_without_validation!` method.
With this you have the flexibility of having validation for all your transitions by default and then skip it wherever required.
Please note that only state column will be updated as mentioned in the above example.
```ruby
job.run_without_validation!
```
If you want to make sure that the _AASM_ column for storing the state is not directly assigned,
configure _AASM_ to not allow direct assignment, like this:
```ruby
class Job < ActiveRecord::Base
include AASM
aasm no_direct_assignment: true do
state :sleeping, initial: true
state :running
event :run do
transitions from: :sleeping, to: :running
end
end
end
```
resulting in this:
```ruby
job = Job.create
job.aasm_state # => 'sleeping'
job.aasm_state = :running # => raises AASM::NoDirectAssignmentError
job.aasm_state # => 'sleeping'
```
### Timestamps
You can tell _AASM_ to try to write a timestamp whenever a new state is entered.
If `timestamps: true` is set, _AASM_ will look for a field named like the new state plus `_at` and try to fill it:
```ruby
class Job < ActiveRecord::Base
include AASM
aasm timestamps: true do
state :sleeping, initial: true
state :running
event :run do
transitions from: :sleeping, to: :running
end
end
end
```
resulting in this:
```ruby
job = Job.create
job.running_at # => nil
job.run!
job.running_at # => 2020-02-20 20:00:00
```
Missing timestamp fields are silently ignored, so it is not necessary to have setters (such as ActiveRecord columns) for *all* states when using this option.
#### ActiveRecord enums
You can use
[enumerations](http://edgeapi.rubyonrails.org/classes/ActiveRecord/Enum.html)
in Rails 4.1+ for your state column:
```ruby
class Job < ActiveRecord::Base
include AASM
enum state: {
sleeping: 5,
running: 99
}
aasm column: :state, enum: true do
state :sleeping, initial: true
state :running
end
end
```
You can explicitly pass the name of the method which provides access
to the enumeration mapping as a value of ```enum```, or you can simply
set it to ```true```. In the latter case AASM will try to use
pluralized column name to access possible enum states.
Furthermore, if your column has integer type (which is normally the
case when you're working with Rails enums), you can omit ```:enum```
setting --- AASM auto-detects this situation and enabled enum
support. If anything goes wrong, you can disable enum functionality
and fall back to the default behavior by setting ```:enum```
to ```false```.
### Sequel
AASM also supports [Sequel](http://sequel.jeremyevans.net/) besides _ActiveRecord_, and _Mongoid_.
```ruby
class Job < Sequel::Model
include AASM
aasm do # default column: aasm_state
...
end
end
```
However it's not yet as feature complete as _ActiveRecord_. For example, there are
scopes defined yet. See [Automatic Scopes](#automatic-scopes).
### Dynamoid
Since version `4.8.0` _AASM_ also supports [Dynamoid](http://joshsymonds.com/Dynamoid/) as
persistence ORM.
### Mongoid
AASM also supports persistence to Mongodb if you're using Mongoid. Make sure
to include Mongoid::Document before you include AASM.
```ruby
class Job
include Mongoid::Document
include AASM
field :aasm_state
aasm do
...
end
end
```
### NoBrainer
AASM also supports persistence to [RethinkDB](https://www.rethinkdb.com/)
if you're using [Nobrainer](http://nobrainer.io/).
Make sure to include NoBrainer::Document before you include AASM.
```ruby
class Job
include NoBrainer::Document
include AASM
field :aasm_state
aasm do
...
end
end
```
### Redis
AASM also supports persistence in Redis via
[Redis::Objects](https://github.com/nateware/redis-objects).
Make sure to include Redis::Objects before you include AASM. Note that non-bang
events will work as bang events, persisting the changes on every call.
```ruby
class User
include Redis::Objects
include AASM
aasm do
end
end
```
### Automatic Scopes
AASM will automatically create scope methods for each state in the model.
```ruby
class Job < ActiveRecord::Base
include AASM
aasm do
state :sleeping, initial: true
state :running
state :cleaning
end
def self.sleeping
"This method name is already in use"
end
end
```
```ruby
class JobsController < ApplicationController
def index
@running_jobs = Job.running
@recent_cleaning_jobs = Job.cleaning.where('created_at >= ?', 3.days.ago)
# @sleeping_jobs = Job.sleeping #=> "This method name is already in use"
end
end
```
If you don't need scopes (or simply don't want them), disable their creation when
defining the `AASM` states, like this:
```ruby
class Job < ActiveRecord::Base
include AASM
aasm create_scopes: false do
state :sleeping, initial: true
state :running
state :cleaning
end
end
```
### Transaction support
Since version *3.0.13* AASM supports ActiveRecord transactions. So whenever a transition
callback or the state update fails, all changes to any database record are rolled back.
Mongodb does not support transactions.
There are currently 3 transactional callbacks that can be handled on the event, and 2 transactional callbacks for all events.
```ruby
event before_all_transactions
event before_transaction
event aasm_fire_event (within transaction)
event after_commit (if event successful)
event after_transaction
event after_all_transactions
```
If you want to make sure a depending action happens only after the transaction is committed,
use the `after_commit` callback along with the auto-save (bang) methods, like this:
```ruby
class Job < ActiveRecord::Base
include AASM
aasm do
state :sleeping, initial: true
state :running
event :run, after_commit: :notify_about_running_job do
transitions from: :sleeping, to: :running
end
end
def notify_about_running_job
...
end
end
job = Job.where(state: 'sleeping').first!
job.run! # Saves the model and triggers the after_commit callback
```
Note that the following will not run the `after_commit` callbacks because
the auto-save method is not used:
```ruby
job = Job.where(state: 'sleeping').first!
job.run
job.save! #notify_about_running_job is not run
```
Please note that `:after_commit` AASM callbacks behaves around custom implementation
of transaction pattern rather than a real-life DB transaction. This fact still causes
the race conditions and redundant callback calls within nested transaction. In order
to fix that it's highly recommended to add `gem 'after_commit_everywhere', '~> 1.0'`
to your `Gemfile`.
If you want to encapsulate state changes within an own transaction, the behavior
of this nested transaction might be confusing. Take a look at
[ActiveRecord Nested Transactions](http://api.rubyonrails.org/classes/ActiveRecord/Transactions/ClassMethods.html)
if you want to know more about this. Nevertheless, AASM by default requires a new transaction
`transaction(requires_new: true)`. You can override this behavior by changing
the configuration
```ruby
class Job < ActiveRecord::Base
include AASM
aasm requires_new_transaction: false do
...
end
...
end
```
which then leads to `transaction(requires_new: false)`, the Rails default.
Additionally, if you do not want any of your ActiveRecord actions to be
wrapped in a transaction, you can specify the `use_transactions` flag. This can
be useful if you want want to persist things to the database that happen as a
result of a transaction or callback, even when some error occurs. The
`use_transactions` flag is true by default.
```ruby
class Job < ActiveRecord::Base
include AASM
aasm use_transactions: false do
...
end
...
end
```
### Pessimistic Locking
AASM supports [ActiveRecord pessimistic locking via `with_lock`](http://api.rubyonrails.org/classes/ActiveRecord/Locking/Pessimistic.html#method-i-with_lock) for database persistence layers.
| Option | Purpose |
| ------ | ------- |
| `false` (default) | No lock is obtained | |
| `true` | Obtain a blocking pessimistic lock e.g. `FOR UPDATE` |
| String | Obtain a lock based on the SQL string e.g. `FOR UPDATE NOWAIT` |
```ruby
class Job < ActiveRecord::Base
include AASM
aasm requires_lock: true do
...
end
...
end
```
```ruby
class Job < ActiveRecord::Base
include AASM
aasm requires_lock: 'FOR UPDATE NOWAIT' do
...
end
...
end
```
### Column name & migration
As a default AASM uses the column `aasm_state` to store the states. You can override
this by defining your favorite column name, using `:column` like this:
```ruby
class Job < ActiveRecord::Base
include AASM
aasm column: :my_state do
...
end
aasm :another_state_machine, column: :second_state do
...
end
end
```
Whatever column name is used, make sure to add a migration to provide this column
(of type `string`).
Do not add default value for column at the database level. If you add default
value in database then AASM callbacks on the initial state will not be fired upon
instantiation of the model.
```ruby
class AddJobState < ActiveRecord::Migration
def self.up
add_column :jobs, :aasm_state, :string
end
def self.down
remove_column :jobs, :aasm_state
end
end
```
### Log State Changes
Logging state change can be done using [paper_trail](https://github.com/paper-trail-gem/paper_trail) gem
Example of implementation can be found here [https://github.com/nitsujri/aasm-papertrail-example](https://github.com/nitsujri/aasm-papertrail-example)
### Inspection
AASM supports query methods for states and events
Given the following `Job` class:
```ruby
class Job
include AASM
aasm do
state :sleeping, initial: true
state :running, :cleaning
event :run do
transitions from: :sleeping, to: :running
end
event :clean do
transitions from: :running, to: :cleaning, guard: :cleaning_needed?
end
event :sleep do
transitions from: [:running, :cleaning], to: :sleeping
end
end
def cleaning_needed?
false
end
end
```
```ruby
# show all states
Job.aasm.states.map(&:name)
#=> [:sleeping, :running, :cleaning]
job = Job.new
# show all permitted states (from initial state)
job.aasm.states(permitted: true).map(&:name)
#=> [:running]
# List all the permitted transitions(event and state pairs) from initial state
job.aasm.permitted_transitions
#=> [{ :event => :run, :state => :running }]
job.run
job.aasm.states(permitted: true).map(&:name)
#=> [:sleeping]
# show all non permitted states
job.aasm.states(permitted: false).map(&:name)
#=> [:cleaning]
# show all possible (triggerable) events from the current state
job.aasm.events.map(&:name)
#=> [:clean, :sleep]
# show all permitted events
job.aasm.events(permitted: true).map(&:name)
#=> [:sleep]
# show all non permitted events
job.aasm.events(permitted: false).map(&:name)
#=> [:clean]
# show all possible events except a specific one
job.aasm.events(reject: :sleep).map(&:name)
#=> [:clean]
# list states for select
Job.aasm.states_for_select
#=> [["Sleeping", "sleeping"], ["Running", "running"], ["Cleaning", "cleaning"]]
# show permitted states with guard parameter
job.aasm.states({permitted: true}, guard_parameter).map(&:name)
```
### Warning output
Warnings are by default printed to `STDERR`. If you want to log those warnings to another output,
use
```ruby
class Job
include AASM
aasm logger: Rails.logger do
...
end
end
```
You can hide warnings by setting `AASM::Configuration.hide_warnings = true`
### RubyMotion support
Now supports [CodeDataQuery](https://github.com/infinitered/cdq.git) !
However I'm still in the process of submitting my compatibility updates to their repository.
In the meantime you can use [my fork](https://github.com/Infotaku/cdq.git), there may still be some minor issues but I intend to extensively use it myself, so fixes should come fast.
Warnings:
- Due to RubyMotion Proc's lack of 'source_location' method, it may be harder
to find out the origin of a "cannot transition from" error. I would recommend using
the 'instance method symbol / string' way whenever possible when defining guardians and callbacks.
### Testing
#### RSpec
AASM provides some matchers for [RSpec](http://rspec.info):
* `transition_from`,
* `have_state`, `allow_event`
* and `allow_transition_to`.
##### Installation Instructions:
* Add `require 'aasm/rspec'` to your `spec_helper.rb` file.
##### Examples Of Usage in Rspec:
```ruby
# classes with only the default state machine
job = Job.new
expect(job).to transition_from(:sleeping).to(:running).on_event(:run)
expect(job).not_to transition_from(:sleeping).to(:cleaning).on_event(:run)
expect(job).to have_state(:sleeping)
expect(job).not_to have_state(:running)
expect(job).to allow_event :run
expect(job).to_not allow_event :clean
expect(job).to allow_transition_to(:running)
expect(job).to_not allow_transition_to(:cleaning)
# on_event also accept multiple arguments
expect(job).to transition_from(:sleeping).to(:running).on_event(:run, :defragmentation)
# classes with multiple state machine
multiple = SimpleMultipleExample.new
expect(multiple).to transition_from(:standing).to(:walking).on_event(:walk).on(:move)
expect(multiple).to_not transition_from(:standing).to(:running).on_event(:walk).on(:move)
expect(multiple).to have_state(:standing).on(:move)
expect(multiple).not_to have_state(:walking).on(:move)
expect(multiple).to allow_event(:walk).on(:move)
expect(multiple).to_not allow_event(:hold).on(:move)
expect(multiple).to allow_transition_to(:walking).on(:move)
expect(multiple).to_not allow_transition_to(:running).on(:move)
expect(multiple).to transition_from(:sleeping).to(:processing).on_event(:start).on(:work)
expect(multiple).to_not transition_from(:sleeping).to(:sleeping).on_event(:start).on(:work)
expect(multiple).to have_state(:sleeping).on(:work)
expect(multiple).not_to have_state(:processing).on(:work)
expect(multiple).to allow_event(:start).on(:move)
expect(multiple).to_not allow_event(:stop).on(:move)
expect(multiple).to allow_transition_to(:processing).on(:move)
expect(multiple).to_not allow_transition_to(:sleeping).on(:move)
# allow_event also accepts arguments
expect(job).to allow_event(:run).with(:defragmentation)
```
#### Minitest
AASM provides assertions and rspec-like expectations for [Minitest](https://github.com/seattlerb/minitest).
##### Assertions
List of supported assertions: `assert_have_state`, `refute_have_state`, `assert_transitions_from`, `refute_transitions_from`, `assert_event_allowed`, `refute_event_allowed`, `assert_transition_to_allowed`, `refute_transition_to_allowed`.
##### Examples Of Usage (Minitest):
Add `require 'aasm/minitest'` to your `test_helper.rb` file and use them like this:
```ruby
# classes with only the default state machine
job = Job.new
assert_transitions_from job, :sleeping, to: :running, on_event: :run
refute_transitions_from job, :sleeping, to: :cleaning, on_event: :run
assert_have_state job, :sleeping
refute_have_state job, :running
assert_event_allowed job, :run
refute_event_allowed job, :clean
assert_transition_to_allowed job, :running
refute_transition_to_allowed job, :cleaning
# on_event also accept arguments
assert_transitions_from job, :sleeping, :defragmentation, to: :running, on_event: :run
# classes with multiple state machine
multiple = SimpleMultipleExample.new
assert_transitions_from multiple, :standing, to: :walking, on_event: :walk, on: :move
refute_transitions_from multiple, :standing, to: :running, on_event: :walk, on: :move
assert_have_state multiple, :standing, on: :move
refute_have_state multiple, :walking, on: :move
assert_event_allowed multiple, :walk, on: :move
refute_event_allowed multiple, :hold, on: :move
assert_transition_to_allowed multiple, :walking, on: :move
refute_transition_to_allowed multiple, :running, on: :move
assert_transitions_from multiple, :sleeping, to: :processing, on_event: :start, on: :work
refute_transitions_from multiple, :sleeping, to: :sleeping, on_event: :start, on: :work
assert_have_state multiple, :sleeping, on: :work
refute_have_state multiple, :processing, on: :work
assert_event_allowed multiple, :start, on: :move
refute_event_allowed multiple, :stop, on: :move
assert_transition_to_allowed multiple, :processing, on: :move
refute_transition_to_allowed multiple, :sleeping, on: :move
```
##### Expectations
List of supported expectations: `must_transition_from`, `wont_transition_from`, `must_have_state`, `wont_have_state`, `must_allow_event`, `wont_allow_event`, `must_allow_transition_to`, `wont_allow_transition_to`.
Add `require 'aasm/minitest_spec'` to your `test_helper.rb` file and use them like this:
```ruby
# classes with only the default state machine
job = Job.new
job.must_transition_from :sleeping, to: :running, on_event: :run
job.wont_transition_from :sleeping, to: :cleaning, on_event: :run
job.must_have_state :sleeping
job.wont_have_state :running
job.must_allow_event :run
job.wont_allow_event :clean
job.must_allow_transition_to :running
job.wont_allow_transition_to :cleaning
# on_event also accept arguments
job.must_transition_from :sleeping, :defragmentation, to: :running, on_event: :run
# classes with multiple state machine
multiple = SimpleMultipleExample.new
multiple.must_transition_from :standing, to: :walking, on_event: :walk, on: :move
multiple.wont_transition_from :standing, to: :running, on_event: :walk, on: :move
multiple.must_have_state :standing, on: :move
multiple.wont_have_state :walking, on: :move
multiple.must_allow_event :walk, on: :move
multiple.wont_allow_event :hold, on: :move
multiple.must_allow_transition_to :walking, on: :move
multiple.wont_allow_transition_to :running, on: :move
multiple.must_transition_from :sleeping, to: :processing, on_event: :start, on: :work
multiple.wont_transition_from :sleeping, to: :sleeping, on_event: :start, on: :work
multiple.must_have_state :sleeping, on: :work
multiple.wont_have_state :processing, on: :work
multiple.must_allow_event :start, on: :move
multiple.wont_allow_event :stop, on: :move
multiple.must_allow_transition_to :processing, on: :move
multiple.wont_allow_transition_to :sleeping, on: :move
```
## <a id="installation">Installation ##
### Manually from RubyGems.org ###
```sh
% gem install aasm
```
### Or if you are using Bundler ###
```ruby
# Gemfile
gem 'aasm'
```
### Building your own gems ###
```sh
% rake build
% sudo gem install pkg/aasm-x.y.z.gem
```
### Generators
After installing AASM you can run generator:
```sh
% rails generate aasm NAME [COLUMN_NAME]
```
Replace NAME with the Model name, COLUMN_NAME is optional(default is 'aasm_state').
This will create a model (if one does not exist) and configure it with aasm block.
For ActiveRecord orm a migration file is added to add aasm state column to table.
### Docker
Run test suite easily on docker
```
1. docker-compose build aasm
2. docker-compose run --rm aasm
```
## Latest changes ##
Take a look at the [CHANGELOG](https://github.com/aasm/aasm/blob/master/CHANGELOG.md) for details about recent changes to the current version.
## Questions? ##
Feel free to
* [create an issue on GitHub](https://github.com/aasm/aasm/issues)
* [ask a question on StackOverflow](http://stackoverflow.com) (tag with `aasm`)
* send us a tweet [@aasm](http://twitter.com/aasm)
## Maintainers ##
* [Scott Barron](https://github.com/rubyist) (2006–2009, original author)
* [Travis Tilley](https://github.com/ttilley) (2009–2011)
* [Thorsten Böttger](http://github.com/alto) (since 2011)
* [Anil Maurya](http://github.com/anilmaurya) (since 2016)
## Stargazers over time
[](https://starchart.cc/aasm/aasm)
## [Contributing](CONTRIBUTING.md)
## Warranty ##
This software is provided "as is" and without any express or
implied warranties, including, without limitation, the implied
warranties of merchantibility and fitness for a particular
purpose.
## License ##
Copyright (c) 2006-2017 Scott Barron
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.