Class: Shipping::ItemMd5Extractor

Inherits:
BaseService show all
Defined in:
app/services/shipping/item_md5_extractor.rb

Overview

Takes an item, looks at shipping dimensions, create a packing entry

Race Condition Note:
This service can be triggered by multiple sources simultaneously:

  1. Item.after_save callback when box dimensions change
  2. Delivery state transitions (picking -> pending_ship_labels, any -> shipped)
  3. Pre-pack workflow calling set_packaged_items_md5_hash

To prevent ActiveRecord::RecordNotUnique errors when two processes try to
create the same Packing (same md5 + service_type), we use upsert which is
atomic at the database level.

Defined Under Namespace

Classes: Result

Instance Attribute Summary collapse

Attributes inherited from BaseService

#options

Instance Method Summary collapse

Methods inherited from BaseService

#log_debug, #log_error, #log_info, #log_warning, #logger, #tagged_logger

Constructor Details

#initialize(options = {}) ⇒ ItemMd5Extractor

Returns a new instance of ItemMd5Extractor.



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# File 'app/services/shipping/item_md5_extractor.rb', line 26

def initialize(options = {})
  @ignore_timestamp = options.delete(:ignore_timestamp).to_b
  super
end

Instance Attribute Details

#ignore_timestamp ⇒ Object (readonly)

Returns the value of attribute ignore_timestamp.



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# File 'app/services/shipping/item_md5_extractor.rb', line 24

def ignore_timestamp
  @ignore_timestamp
end

Instance Method Details

#process(item) ⇒ Object 



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# File 'app/services/shipping/item_md5_extractor.rb', line 31

def process(item)
  result = Result.new

  logger.tagged("Item:#{item.id}") do
    # We only create packaging for goods
    # We only create packaging if shipping dimensions are present? (just in case validation didn't catch it)
    unless item.is_goods? && item.box1_defined?
      result.message = msg = "Item #{item.id} is not a good or has no shipping dimensions"
      logger.warn msg
      return result
    end

    md5_result = Shipping::Md5HashItem.process(item)
    logger.info "item md5: #{md5_result.md5}, item string: #{md5_result.items_string}"
    result.item_md5 = md5_result.md5

    # Create a packing for this single item
    service_type = Packing.service_types[item.shipping_class]
    raise "Unable to match item shipping class #{item.shipping_class}" unless service_type

    # Skip when a higher-authority fresh row already exists (Packing#authoritative_over?).
    # Consolidates the previous two ad-hoc checks (recency vs `item.updated_at` and
    # the hard-coded from_delivery/from_manual_entry block list) into the same
    # origin-rank + freshness gate that DeliveryMd5Extractor uses.
    existing_packing = Packing.find_by(md5: md5_result.md5, service_type:)
    if existing_packing && !ignore_timestamp && existing_packing.authoritative_over?(:from_item)
      result.message = msg = "Existing #{existing_packing.origin} packing #{existing_packing.id} outranks incoming from_item (last updated #{existing_packing.updated_at}); skip saving"
      logger.info msg
      return result
    end

    # Build packing attributes
    contents = if item.ships_in_single_box?
                 md5_result.full_item_id_hash
               else
                 item.get_multi_box_item_contents_item_id_hash_array
               end

    packdims = item.to_packdims
    packdim_contents = Packing.format_packdim_contents(md5: md5_result.md5, contents: contents, packdims: packdims)

    packing_timestamp = item.updated_at || item.created_at

    # Use upsert to atomically insert or update - prevents race condition when
    # multiple workers try to create the same packing simultaneously
    Packing.upsert(
      {
        md5: md5_result.md5,
        service_type:,
        origin: Packing.origins[:from_item],
        packdims: packdims,
        contents:,
        packdim_contents: packdim_contents.to_json,
        item_id: item.id,
        delivery_id: nil,
        shipment_id: nil,
        created_at: packing_timestamp,
        updated_at: Time.current
      },
      unique_by: :index_packings_on_md5_and_service_type
    )

    # Reload the packing to get the record (upsert doesn't return the full object)
    packing = Packing.find_by(md5: md5_result.md5, service_type:)
    unless packing
      msg = "Packing upsert did not persist (weight audit or DB); item #{item.id} md5=#{md5_result.md5}"
      result.message = msg
      logger.warn msg
      return result
    end

    # Link kit item IDs for searchability (use union to avoid duplicates)
    packing.item_ids |= md5_result.kit_item_ids

    result.packings << packing
    logger.info "Packing #{packing.id} upserted successfully for item #{item.id}"
  end

  result
end