Merge pull request #3869 from rubyforgood/event-source

Initial event sourcing implementation

Gemfile

@@ -35,6 +35,8 @@ gem "paper_trail"
 gem "rolify", "~> 6.0"
 # Enforces "safe" migrations.
 gem "strong_migrations", "1.6.3"
+# used in events
+gem 'dry-struct'
 
 ##### JAVSCRIPT/CSS/ASSETS #######
 

Gemfile.lock

@@ -162,6 +162,25 @@ GEM
     dotenv-rails (2.8.1)
       dotenv (= 2.8.1)
       railties (>= 3.2)
+    dry-core (1.0.1)
+      concurrent-ruby (~> 1.0)
+      zeitwerk (~> 2.6)
+    dry-inflector (1.0.0)
+    dry-logic (1.5.0)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 1.0, < 2)
+      zeitwerk (~> 2.6)
+    dry-struct (1.6.0)
+      dry-core (~> 1.0, < 2)
+      dry-types (>= 1.7, < 2)
+      ice_nine (~> 0.11)
+      zeitwerk (~> 2.6)
+    dry-types (1.7.1)
+      concurrent-ruby (~> 1.0)
+      dry-core (~> 1.0)
+      dry-inflector (~> 1.0)
+      dry-logic (~> 1.4)
+      zeitwerk (~> 2.6)
     erubi (1.12.0)
     et-orbi (1.2.7)
       tzinfo
@@ -246,6 +265,7 @@ GEM
     icalendar (2.9.0)
       ice_cube (~> 0.16)
     ice_cube (0.16.4)
+    ice_nine (0.11.2)
     image_processing (1.12.2)
       mini_magick (>= 4.9.5, < 5)
       ruby-vips (>= 2.0.17, < 3)
@@ -653,6 +673,7 @@ DEPENDENCIES
   devise_invitable
   discard (~> 1.3)
   dotenv-rails
+  dry-struct
   factory_bot_rails
   faker
   filterrific

app/controllers/audits_controller.rb

@@ -40,6 +40,7 @@ def finalize
     ActiveRecord::Base.transaction do
       @audit.storage_location.increase_inventory increasing_adjustment
       @audit.storage_location.decrease_inventory decreasing_adjustment
+      AuditEvent.publish(@audit)
     end
     @audit.finalized!
     redirect_to audit_path(@audit), notice: "Audit is Finalized."

app/controllers/donations_controller.rb

@@ -43,8 +43,7 @@ def index
   def create
     @donation = current_organization.donations.new(donation_params)
 
-    if @donation.save
-      @donation.storage_location.increase_inventory @donation
+    if DonationCreateService.call(@donation)
       flash[:notice] = "Donation created and logged!"
       redirect_to donations_path
     else
@@ -75,7 +74,10 @@ def show
 
   def update
     @donation = Donation.find(params[:id])
-    ItemizableUpdateService.call(itemizable: @donation, params: donation_params, type: :increase)
+    ItemizableUpdateService.call(itemizable: @donation,
+      params: donation_params,
+      type: :increase,
+      event_class: DonationEvent)
     redirect_to donations_path
   rescue => e
     flash[:alert] = "Error updating donation: #{e.message}"

app/controllers/purchases_controller.rb

@@ -32,8 +32,7 @@ def index
 
   def create
     @purchase = current_organization.purchases.new(purchase_params)
-    if @purchase.save
-      @purchase.storage_location.increase_inventory @purchase
+    if PurchaseCreateService.call(@purchase)
       flash[:notice] = "New Purchase logged!"
       redirect_to purchases_path
     else
@@ -64,7 +63,10 @@ def show
 
   def update
     @purchase = current_organization.purchases.find(params[:id])
-    ItemizableUpdateService.call(itemizable: @purchase, params: purchase_params, type: :increase)
+    ItemizableUpdateService.call(itemizable: @purchase,
+      params: purchase_params,
+      type: :increase,
+      event_class: PurchaseEvent)
     redirect_to purchases_path
   rescue => e
     load_form_collections
@@ -73,11 +75,8 @@ def update
   end
 
   def destroy
-    ActiveRecord::Base.transaction do
-      purchase = current_organization.purchases.find(params[:id])
-      purchase.storage_location.decrease_inventory(purchase)
-      purchase.destroy!
-    end
+    purchase = current_organization.purchases.find(params[:id])
+    PurchaseDestroyService.call(purchase)
 
     flash[:notice] = "Purchase #{params[:id]} has been removed!"
     redirect_to purchases_path

app/controllers/transfers_controller.rb

@@ -22,17 +22,8 @@ def index
   def create
     @transfer = current_organization.transfers.new(transfer_params)
 
-    if @transfer.valid?
-      ActiveRecord::Base.transaction do
-        @transfer.save
-        @transfer.from.decrease_inventory @transfer
-        @transfer.to.increase_inventory @transfer
-      end
-
-      redirect_to transfers_path, notice: "#{@transfer.line_items.total} items have been transferred from #{@transfer.from.name} to #{@transfer.to.name}!"
-    else
-      raise StandardError.new(@transfer.errors.full_messages.join("</br>"))
-    end
+    TransferCreateService.call(@transfer)
+    redirect_to transfers_path, notice: "#{@transfer.line_items.total} items have been transferred from #{@transfer.from.name} to #{@transfer.to.name}!"
   rescue StandardError => e
     flash[:error] = e.message
     load_form_collections

app/events/adjustment_event.rb

@@ -0,0 +1,13 @@
+class AdjustmentEvent < Event
+  # @param adjustment [Adjustment]
+  def self.publish(adjustment)
+    create(
+      eventable: adjustment,
+      organization_id: adjustment.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::InventoryPayload.new(
+        items: EventTypes::EventLineItem.from_line_items(adjustment.line_items, to: adjustment.storage_location_id)
+      )
+    )
+  end
+end

app/events/audit_event.rb

@@ -0,0 +1,16 @@
+class AuditEvent < Event
+  serialize :data, EventTypes::StructCoder.new(EventTypes::AuditPayload)
+
+  # @param audit [Audit]
+  def self.publish(audit)
+    create(
+      eventable: audit,
+      organization_id: audit.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::AuditPayload.new(
+        storage_location_id: audit.storage_location_id,
+        items: EventTypes::EventLineItem.from_line_items(audit.line_items, to: audit.storage_location_id)
+      )
+    )
+  end
+end

app/events/distribution_destroy_event.rb

@@ -0,0 +1,13 @@
+class DistributionDestroyEvent < Event
+  # @param distribution [Distribution]
+  def self.publish(distribution)
+    create(
+      eventable: distribution,
+      organization_id: distribution.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::InventoryPayload.new(
+        items: EventTypes::EventLineItem.from_line_items(distribution.line_items, to: distribution.storage_location_id)
+      )
+    )
+  end
+end

app/events/distribution_event.rb

@@ -0,0 +1,13 @@
+class DistributionEvent < Event
+  # @param distribution [Distribution]
+  def self.publish(distribution)
+    create(
+      eventable: distribution,
+      organization_id: distribution.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::InventoryPayload.new(
+        items: EventTypes::EventLineItem.from_line_items(distribution.line_items, from: distribution.storage_location_id)
+      )
+    )
+  end
+end

app/events/donation_destroy_event.rb

@@ -0,0 +1,13 @@
+class DonationDestroyEvent < Event
+  # @param donation [Donation]
+  def self.publish(donation)
+    create(
+      eventable: donation,
+      organization_id: donation.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::InventoryPayload.new(
+        items: EventTypes::EventLineItem.from_line_items(donation.line_items, from: donation.storage_location_id)
+      )
+    )
+  end
+end

app/events/donation_event.rb

@@ -0,0 +1,13 @@
+class DonationEvent < Event
+  # @param donation [Donation]
+  def self.publish(donation)
+    create(
+      eventable: donation,
+      organization_id: donation.organization_id,
+      event_time: Time.zone.now,
+      data: EventTypes::InventoryPayload.new(
+        items: EventTypes::EventLineItem.from_line_items(donation.line_items, to: donation.storage_location_id)
+      )
+    )
+  end
+end

app/events/event_types/audit_payload.rb

@@ -0,0 +1,9 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class AuditPayload < InventoryPayload
+    attribute :storage_location_id, Types::Integer
+  end
+end

app/events/event_types/event_item.rb

@@ -0,0 +1,11 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class EventItem < Dry::Struct
+    transform_keys(&:to_sym)
+    attribute :item_id, Types::Integer
+    attribute :quantity, Types::Integer
+  end
+end

app/events/event_types/event_line_item.rb

@@ -0,0 +1,36 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class EventLineItem < Dry::Struct
+    transform_keys(&:to_sym)
+    attribute :quantity, Types::Integer # can be positive or negative
+    attribute :item_id, Types::Integer
+    attribute :item_value_in_cents, Types::Integer
+    attribute :from_storage_location, Types::Integer.optional
+    attribute :to_storage_location, Types::Integer.optional
+
+    # @param line_item [LineItem]
+    # @param from [Integer]
+    # @param to [Integer]
+    # @return [EventLineItem]
+    def self.from_line_item(line_item, from: nil, to: nil)
+      new(
+        quantity: line_item.quantity,
+        item_id: line_item.item_id,
+        item_value_in_cents: line_item.item.value_in_cents,
+        from_storage_location: from,
+        to_storage_location: to
+      )
+    end
+
+    # @param line_item [Array<LineItem>]
+    # @param from [Integer]
+    # @param to [Integer]
+    # @return [Array<EventLineItem>]
+    def self.from_line_items(line_items, from: nil, to: nil)
+      line_items.map { |i| from_line_item(i, from: from, to: to) }
+    end
+  end
+end

app/events/event_types/event_storage_location.rb

@@ -0,0 +1,51 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class EventStorageLocation < Dry::Struct
+    transform_keys(&:to_sym)
+
+    attribute :id, Types::Integer
+    attribute :items, Types::Hash.map(Types::Coercible::Integer, EventTypes::EventItem)
+
+    # @param storage_location [StorageLocation]
+    # @return [EventTypes::EventStorageLocation]
+    def self.from(storage_location)
+      new(id: storage_location.id, items: {})
+    end
+
+    def reset!
+      items.clear
+    end
+
+    # @param item_id [Integer]
+    # @param quantity [Integer]
+    def set_inventory(item_id, quantity)
+      items[item_id] = EventTypes::EventItem.new(item_id: item_id, quantity: quantity)
+    end
+
+    # @param item_id [Integer]
+    # @param quantity [Integer]
+    # @param validate [Boolean]
+    def reduce_inventory(item_id, quantity, validate: true)
+      if validate
+        if items[item_id].nil?
+          raise "Item #{item_id} not found in storage location #{id}"
+        end
+        if items[item_id].quantity < quantity
+          raise "Could not reduce quantity by #{quantity} for item #{item_id} in storage location #{id} - current quantity is #{items[item_id].quantity}"
+        end
+      end
+      current_quantity = items[item_id]&.quantity || 0
+      items[item_id] = EventTypes::EventItem.new(item_id: item_id, quantity: current_quantity - quantity)
+    end
+
+    # @param item_id [Integer]
+    # @param quantity [Integer]
+    def add_inventory(item_id, quantity)
+      current_quantity = items[item_id]&.quantity || 0
+      items[item_id] = EventTypes::EventItem.new(item_id: item_id, quantity: current_quantity + quantity)
+    end
+  end
+end

app/events/event_types/inventory.rb

@@ -0,0 +1,32 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class Inventory < Dry::Struct
+    transform_keys(&:to_sym)
+    attribute :organization_id, Types::Integer
+    attribute :storage_locations, Types::Hash.map(Types::Coercible::Integer, EventTypes::EventStorageLocation)
+
+    # @param organization_id [Integer]
+    # @return [EventTypes::Inventory]
+    def self.from(organization_id)
+      org = Organization.find(organization_id)
+      new(organization_id: organization_id,
+        storage_locations: org.storage_locations.map { |s| [s.id, EventTypes::EventStorageLocation.from(s)] }.to_h)
+    end
+
+    def move_item(item_id:, quantity:, from_location: nil, to_location: nil, validate: true)
+      if from_location
+        if storage_locations[from_location].nil? && validate
+          raise "Storage location #{from_location} not found!"
+        end
+        storage_locations[from_location] ||= EventTypes::EventStorageLocation.new(id: from_location, items: {})
+        storage_locations[from_location].reduce_inventory(item_id, quantity, validate: validate)
+      end
+      if to_location
+        storage_locations[to_location].add_inventory(item_id, quantity)
+      end
+    end
+  end
+end

app/events/event_types/inventory_payload.rb

@@ -0,0 +1,11 @@
+module Types
+  include Dry.Types()
+end
+
+module EventTypes
+  class InventoryPayload < Dry::Struct
+    transform_keys(&:to_sym)
+
+    attribute :items, Types::Array.of(EventTypes::EventLineItem)
+  end
+end

app/events/event_types/struct_coder.rb

@@ -0,0 +1,19 @@
+# see https://discourse.dry-rb.org/t/dry-struct-and-serializer/1517/2
+module EventTypes
+  class StructCoder
+    attr_reader :struct
+
+    def initialize(struct)
+      @struct = struct
+    end
+
+    def dump(s)
+      s.to_hash
+    end
+
+    def load(h)
+      return if h.nil?
+      struct.new(h.with_indifferent_access)
+    end
+  end
+end