Class: Ruote::StorageParticipant

Inherits:
Object
  • Object
show all
Includes:
Enumerable, LocalParticipant
Defined in:
lib/ruote/part/storage_participant.rb

Overview

A participant that stores the workitem in the same storage used by the engine and the worker(s).

part = engine.register_participant 'alfred', Ruote::StorageParticipant

# ... a bit later

puts "workitems still open : "
part.each do |workitem|
  puts "#{workitem.fei.wfid} - #{workitem.fields['params']['task']}"
end

# ... when done with a workitem

part.reply(workitem)
  # this will remove the workitem from the storage and hand it back
  # to the engine

Does not thread by default (the engine will not spawn a dedicated thread to handle the delivery to this participant, the workitem will get stored via the main engine thread and basta).

Instance Attribute Summary

Attributes included from LocalParticipant

#context, #error, #fei, #flavour, #msg, #workitem

Class Method Summary (collapse)

Instance Method Summary (collapse)

Methods included from Enumerable

#each_with_object

Methods included from LocalParticipant

#_accept?, #_dont_thread?, #_on_cancel, #_on_reply, #_on_workitem, #_rtimeout, #applied_workitem, #fexp, #is_cancelled?, #is_gone?, #lookup_variable, #participant_name, #re_dispatch, #reply_to_engine, #unschedule_re_dispatch

Methods included from ReceiverMixin

#fetch_flow_expression, #fetch_workitem, #launch, #receive, #sign

Constructor Details

- (StorageParticipant) initialize(engine_or_options = {}, options = nil)

Returns a new instance of StorageParticipant



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# File 'lib/ruote/part/storage_participant.rb', line 58

def initialize(engine_or_options={}, options=nil)

  if engine_or_options.respond_to?(:context)
    @context = engine_or_options.context
  elsif engine_or_options.is_a?(Ruote::Context)
    @context = engine_or_options
  else
    @options = engine_or_options
  end

  @options ||= {}

  @store_name = @options['store_name']
end

Class Method Details

+ (Boolean) matches?(hwi, pname, criteria)

Used by #query when filtering workitems.

Returns:

  • (Boolean)


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# File 'lib/ruote/part/storage_participant.rb', line 331

def self.matches?(hwi, pname, criteria)

  return false if pname && hwi['participant_name'] != pname

  fields = hwi['fields']

  criteria.each do |fname, fvalue|
    return false if fields[fname] != fvalue
  end

  true
end

Instance Method Details

- (Object) [](fei) Also known as: by_fei

Given a fei (or its string version, a sid), returns the corresponding workitem (or nil).



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# File 'lib/ruote/part/storage_participant.rb', line 144

def [](fei)

  doc = fetch(fei)

  doc ? Ruote::Workitem.new(doc) : nil
end

- (Object) all(opts = {})

Returns all the workitems stored in here.



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# File 'lib/ruote/part/storage_participant.rb', line 209

def all(opts={})

  res = fetch_all(opts)

  res.is_a?(Array) ? res.map { |hwi| Ruote::Workitem.new(hwi) } : res
end

- (Object) by_field(field, value = nil, opts = {})

field : returns all the workitems with the given field name present.

field and value : returns all the workitems with the given field name and the given value for that field.

Warning : only some storages are optimized for such queries (like CouchStorage), the others will load all the workitems and then filter them.



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# File 'lib/ruote/part/storage_participant.rb', line 257

def by_field(field, value=nil, opts={})

  (value, opts = nil, value) if value.is_a?(Hash)

  if @context.storage.respond_to?(:by_field)
    return @context.storage.by_field('workitems', field, value, opts)
  end

  do_select(opts) do |hwi|
    hwi['fields'].keys.include?(field) &&
    (value.nil? || hwi['fields'][field] == value)
  end
end

- (Object) by_participant(participant_name, opts = {})

Returns all workitems for the specified participant name



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# File 'lib/ruote/part/storage_participant.rb', line 237

def by_participant(participant_name, opts={})

  return @context.storage.by_participant(
    'workitems', participant_name, opts
  ) if @context.storage.respond_to?(:by_participant)

  do_select(opts) do |hwi|
    hwi['participant_name'] == participant_name
  end
end

- (Object) by_wfid(wfid, opts = {})

Return all workitems for the specified wfid



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# File 'lib/ruote/part/storage_participant.rb', line 226

def by_wfid(wfid, opts={})

  if @context.storage.respond_to?(:by_wfid)
    return @context.storage.by_wfid('workitems', wfid, opts)
  end

  wis(@context.storage.get_many('workitems', wfid, opts))
end

- (Object) delegate(workitem, new_owner)

Delegates a currently owned workitem to a new owner.

Fails if the workitem can't be found, belongs to noone, or if the workitem passed as argument is out of date (got modified in the mean time).

It's OK to delegate to nil, thus freeing the workitem.

See #reserve for an an explanation of the reserve/delegate/proceed flow.



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# File 'lib/ruote/part/storage_participant.rb', line 405

def delegate(workitem, new_owner)

  hwi = fetch(workitem)

  fail ArgumentError.new(
    "workitem not found"
  ) if hwi == nil

  fail ArgumentError.new(
    "cannot delegate, workitem doesn't belong to anyone"
  ) if hwi['owner'] == nil

  fail ArgumentError.new(
    "cannot delegate, " +
    "workitem owned by '#{hwi['owner']}', not '#{workitem.owner}'"
  ) if hwi['owner'] != workitem.owner

  hwi['owner'] = new_owner

  r = @context.storage.put(hwi, :update_rev => true)

  fail ArgumentError.new("workitem is gone") if r == true
  fail ArgumentError.new("workitem got modified meanwhile") if r != nil

  Workitem.new(hwi)
end

- (Object) do_not_thread

No need for a separate thread when delivering to this participant.



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# File 'lib/ruote/part/storage_participant.rb', line 75

def do_not_thread; true; end

- (Object) do_update(workitem = @workitem)

Added for groups.google.com/forum/?fromgroups#!topic/openwferu-users/5bpV2yfKwM0

Makes sure the workitem get saved to the storage. Fails if the workitem is already gone. Returns nil in case of success.



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# File 'lib/ruote/part/storage_participant.rb', line 115

def do_update(workitem=@workitem)

  r = update(workitem)

  fail ArgumentError.new("workitem is gone") if r == true
  return nil if r.nil?

  r.h['fields'] = workitem.fields
  do_update(r)
end

- (Object) each(&block)

Iterates over the workitems stored in here.



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# File 'lib/ruote/part/storage_participant.rb', line 202

def each(&block)

  all.each { |wi| block.call(wi) }
end

- (Object) first

A convenience method (especially when testing), returns the first (only ?) workitem in the participant.



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# File 'lib/ruote/part/storage_participant.rb', line 219

def first

  wi(fetch_all({}).first)
end

- (Object) flunk(workitem, err_class_or_instance, *err_arguments)

Removes the workitem and hands it back to the flow with an error to raise for the participant expression that emitted the workitem.



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# File 'lib/ruote/part/storage_participant.rb', line 169

def flunk(workitem, err_class_or_instance, *err_arguments)

  r = remove_workitem('reject', workitem)

  return flunk(workitem) if r != nil

  workitem.h.delete('_rev')

  super(workitem, err_class_or_instance, *err_arguments)
end

- (Object) on_cancel

Removes the document/workitem from the storage.

Warning: this method is called by the engine (worker), i.e. not by you.



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# File 'lib/ruote/part/storage_participant.rb', line 130

def on_cancel

  doc = fetch(fei)

  return unless doc

  r = @context.storage.delete(doc)

  on_cancel(fei, flavour) if r != nil
end

- (Object) on_workitem

This is the method called by ruote when passing a workitem to this participant.



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# File 'lib/ruote/part/storage_participant.rb', line 80

def on_workitem

  doc = workitem.to_h

  doc.merge!(
    'type' => 'workitems',
    '_id' => to_id(doc['fei']),
    'participant_name' => doc['participant_name'],
    'wfid' => doc['fei']['wfid'])

  doc['store_name'] = @store_name if @store_name

  @context.storage.put(doc, :update_rev => true)
end

- (Object) per_participant

Mostly a test method. Returns a Hash were keys are participant names and values are lists of workitems.



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# File 'lib/ruote/part/storage_participant.rb', line 347

def per_participant

  each_with_object({}) { |wi, h| (h[wi.participant_name] ||= []) << wi }
end

- (Object) per_participant_count

Mostly a test method. Returns a Hash were keys are participant names and values are integers, the count of workitems for a given participant name.



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# File 'lib/ruote/part/storage_participant.rb', line 356

def per_participant_count

  per_participant.remap { |(k, v), h| h[k] = v.size }
end

- (Object) proceed(workitem)

Removes the workitem from the storage and replies to the engine.



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# File 'lib/ruote/part/storage_participant.rb', line 155

def proceed(workitem)

  r = remove_workitem('proceed', workitem)

  return proceed(workitem) if r != nil

  workitem.h.delete('_rev')

  reply_to_engine(workitem)
end

- (Object) purge!

Cleans this participant out completely



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# File 'lib/ruote/part/storage_participant.rb', line 324

def purge!

  fetch_all({}).each { |hwi| @context.storage.delete(hwi) }
end

- (Object) query(criteria)

Queries the store participant for workitems.

Some examples :

part.query(:wfid => @wfid).size
part.query('place' => 'nara').size
part.query('place' => 'heiankyou').size
part.query(:wfid => @wfid, :place => 'heiankyou').size

There are two 'reserved' criterion : 'wfid' and 'participant' ('participant_name' as well). The rest of the criteria are considered constraints for fields.

'offset' and 'limit' are reserved as well. They should prove useful for pagination. 'skip' can be used instead of 'offset'.

Note : the criteria is AND only, you'll have to do ORs (aggregation) by yourself.



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# File 'lib/ruote/part/storage_participant.rb', line 290

def query(criteria)

  cr = Ruote.keys_to_s(criteria)

  if @context.storage.respond_to?(:query_workitems)
    return @context.storage.query_workitems(cr)
  end

  opts = {}
  opts[:skip] = cr.delete('offset') || cr.delete('skip')
  opts[:limit] = cr.delete('limit')
  opts[:count] = cr.delete('count')

  wfid = cr.delete('wfid')

  count = opts[:count]

  pname = cr.delete('participant_name') || cr.delete('participant')
  opts.delete(:count) if pname

  hwis = wfid ?
    @context.storage.get_many('workitems', wfid, opts) : fetch_all(opts)

  return hwis unless hwis.is_a?(Array)

  hwis = hwis.select { |hwi|
    Ruote::StorageParticipant.matches?(hwi, pname, cr)
  }

  count ? hwis.size : wis(hwis)
end

- (Object) reply(workitem)

(soon to be removed)



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# File 'lib/ruote/part/storage_participant.rb', line 182

def reply(workitem)

  puts '-' * 80
  puts '*** WARNING : please use the Ruote::StorageParticipant#proceed(wi)'
  puts '              instead of #reply(wi) which is deprecated'
  #caller.each { |l| puts l }
  puts '-' * 80

  proceed(workitem)
end

- (Object) reserve(workitem_or_fei, owner)

Claims a workitem. Returns the [updated] workitem if successful.

Returns nil if the workitem is already reserved.

Fails if the workitem can't be found, is gone, or got modified elsewhere.

Here is a mini-diagram explaining the reserve/delegate/proceed flow:

 in    delegate(nil)    delegate(other)
 |    +---------------+ +------+
 v    v               | |      v
+-------+  reserve   +----------+  proceed
| ready | ---------> | reserved | ---------> out
+-------+            +----------+


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# File 'lib/ruote/part/storage_participant.rb', line 377

def reserve(workitem_or_fei, owner)

  hwi = fetch(workitem_or_fei)

  fail ArgumentError.new("workitem not found") if hwi.nil?

  return nil if hwi['owner'] && hwi['owner'] != owner

  hwi['owner'] = owner

  r = @context.storage.put(hwi, :update_rev => true)

  fail ArgumentError.new("workitem is gone") if r == true
  fail ArgumentError.new("workitem got modified meanwhile") if r != nil

  Workitem.new(hwi)
end

- (Object) size

Returns the count of workitems stored in this participant.



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# File 'lib/ruote/part/storage_participant.rb', line 195

def size

  fetch_all(:count => true)
end

- (Object) update(workitem)

Used by client code when “saving” a workitem (fields may have changed). Calling #update won't proceed the workitem.

Returns nil in case of success, true if the workitem is already gone and the newer version of the workitem if the workitem changed in the mean time.



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# File 'lib/ruote/part/storage_participant.rb', line 102

def update(workitem)

  r = @context.storage.put(workitem.to_h, :update_rev => true)

  r.is_a?(Hash) ? Ruote::Workitem.new(r) : r
end