chore: initial commit

internal/svc/shipping/api/gateway.go

@@ -0,0 +1,39 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"context"
+
+	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
+	"github.com/rs/zerolog/log"
+
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+	"github.com/hexolan/stocklet/internal/pkg/serve"
+	"github.com/hexolan/stocklet/internal/svc/shipping"
+)
+
+func PrepareGateway(cfg *shipping.ServiceConfig) *runtime.ServeMux {
+	mux, clientOpts := serve.NewGatewayServeBase(&cfg.Shared)
+
+	ctx := context.Background()
+	err := pb.RegisterShippingServiceHandlerFromEndpoint(ctx, mux, serve.GetAddrToGrpc("localhost"), clientOpts)
+	if err != nil {
+		log.Panic().Err(err).Msg("failed to register endpoint for gateway")
+	}
+
+	return mux
+}

internal/svc/shipping/api/grpc.go

@@ -0,0 +1,30 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"google.golang.org/grpc"
+
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+	"github.com/hexolan/stocklet/internal/pkg/serve"
+	"github.com/hexolan/stocklet/internal/svc/shipping"
+)
+
+func PrepareGrpc(cfg *shipping.ServiceConfig, svc *shipping.ShippingService) *grpc.Server {
+	svr := serve.NewGrpcServeBase(&cfg.Shared)
+	pb.RegisterShippingServiceServer(svr, svc)
+	return svr
+}

internal/svc/shipping/config.go

@@ -0,0 +1,42 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package shipping
+
+import (
+	"github.com/hexolan/stocklet/internal/pkg/config"
+)
+
+// Order Service Configuration
+type ServiceConfig struct {
+	// Core Configuration
+	Shared config.SharedConfig
+
+	// Dynamically loaded configuration
+	Postgres config.PostgresConfig
+	Kafka    config.KafkaConfig
+}
+
+// load the base service configuration
+func NewServiceConfig() (*ServiceConfig, error) {
+	cfg := ServiceConfig{}
+
+	// Load the core configuration
+	if err := cfg.Shared.Load(); err != nil {
+		return nil, err
+	}
+
+	return &cfg, nil
+}

internal/svc/shipping/controller/kafka.go

@@ -0,0 +1,135 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package controller
+
+import (
+	"context"
+
+	"github.com/rs/zerolog/log"
+	"github.com/twmb/franz-go/pkg/kgo"
+	"google.golang.org/protobuf/proto"
+
+	"github.com/hexolan/stocklet/internal/pkg/messaging"
+	eventpb "github.com/hexolan/stocklet/internal/pkg/protogen/events/v1"
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+	"github.com/hexolan/stocklet/internal/svc/shipping"
+)
+
+type kafkaController struct {
+	cl *kgo.Client
+
+	svc pb.ShippingServiceServer
+
+	ctx       context.Context
+	ctxCancel context.CancelFunc
+}
+
+func NewKafkaController(cl *kgo.Client) shipping.ConsumerController {
+	// Create a cancellable context for the consumer
+	ctx, ctxCancel := context.WithCancel(context.Background())
+
+	// Ensure the required Kafka topics exist
+	err := messaging.EnsureKafkaTopics(
+		cl,
+
+		messaging.Shipping_Shipment_Allocation_Topic,
+		messaging.Shipping_Shipment_Dispatched_Topic,
+
+		messaging.Warehouse_Reservation_Reserved_Topic,
+
+		messaging.Payment_Processing_Topic,
+	)
+	if err != nil {
+		log.Warn().Err(err).Msg("kafka: raised attempting to ensure svc topics")
+	}
+
+	// Add the consumption topics
+	cl.AddConsumeTopics(
+		messaging.Warehouse_Reservation_Reserved_Topic,
+		messaging.Payment_Processing_Topic,
+	)
+
+	return &kafkaController{cl: cl, ctx: ctx, ctxCancel: ctxCancel}
+}
+
+func (c *kafkaController) Attach(svc pb.ShippingServiceServer) {
+	c.svc = svc
+}
+
+func (c *kafkaController) Start() {
+	if c.svc == nil {
+		log.Panic().Msg("consumer: no service interface attached")
+	}
+
+	for {
+		fetches := c.cl.PollFetches(c.ctx)
+		if errs := fetches.Errors(); len(errs) > 0 {
+			log.Panic().Any("kafka-errs", errs).Msg("consumer: unrecoverable kafka errors")
+		}
+
+		fetches.EachTopic(func(ft kgo.FetchTopic) {
+			switch ft.Topic {
+			case messaging.Warehouse_Reservation_Reserved_Topic:
+				c.consumeStockReservationEventTopic(ft)
+			case messaging.Payment_Processing_Topic:
+				c.consumePaymentProcessedEventTopic(ft)
+			default:
+				log.Warn().Str("topic", ft.Topic).Msg("consumer: recieved records from unexpected topic")
+			}
+		})
+	}
+}
+
+func (c *kafkaController) Stop() {
+	// Cancel the consumer context
+	c.ctxCancel()
+}
+
+func (c *kafkaController) consumeStockReservationEventTopic(ft kgo.FetchTopic) {
+	log.Info().Str("topic", ft.Topic).Msg("consumer: recieved records from topic")
+
+	// Process each message from the topic
+	ft.EachRecord(func(record *kgo.Record) {
+		// Unmarshal the event
+		var event eventpb.StockReservationEvent
+		err := proto.Unmarshal(record.Value, &event)
+		if err != nil {
+			log.Panic().Err(err).Msg("consumer: failed to unmarshal event")
+		}
+
+		// Process the event
+		ctx := context.Background()
+		c.svc.ProcessStockReservationEvent(ctx, &event)
+	})
+}
+
+func (c *kafkaController) consumePaymentProcessedEventTopic(ft kgo.FetchTopic) {
+	log.Info().Str("topic", ft.Topic).Msg("consumer: recieved records from topic")
+
+	// Process each message from the topic
+	ft.EachRecord(func(record *kgo.Record) {
+		// Unmarshal the event
+		var event eventpb.PaymentProcessedEvent
+		err := proto.Unmarshal(record.Value, &event)
+		if err != nil {
+			log.Panic().Err(err).Msg("consumer: failed to unmarshal event")
+		}
+
+		// Process the event
+		ctx := context.Background()
+		c.svc.ProcessPaymentProcessedEvent(ctx, &event)
+	})
+}

internal/svc/shipping/controller/postgres.go

@@ -0,0 +1,256 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package controller
+
+import (
+	"context"
+
+	"github.com/doug-martin/goqu/v9"
+	_ "github.com/doug-martin/goqu/v9/dialect/postgres"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgtype"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"github.com/hexolan/stocklet/internal/pkg/errors"
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+	"github.com/hexolan/stocklet/internal/svc/shipping"
+)
+
+const (
+	pgShipmentBaseQuery      string = "SELECT id, order_id, dispatched, created_at FROM shipments"
+	pgShipmentItemsBaseQuery string = "SELECT shipment_id, product_id, quantity FROM shipment_items"
+)
+
+type postgresController struct {
+	cl *pgxpool.Pool
+}
+
+func NewPostgresController(cl *pgxpool.Pool) shipping.StorageController {
+	return postgresController{cl: cl}
+}
+
+func (c postgresController) GetShipment(ctx context.Context, shipmentId string) (*pb.Shipment, error) {
+	return c.getShipment(ctx, nil, shipmentId)
+}
+
+func (c postgresController) getShipment(ctx context.Context, tx *pgx.Tx, shipmentId string) (*pb.Shipment, error) {
+	// Determine if a db transaction is being used
+	var row pgx.Row
+	const query = pgShipmentBaseQuery + " WHERE id=$1"
+	if tx == nil {
+		row = c.cl.QueryRow(ctx, query, shipmentId)
+	} else {
+		row = (*tx).QueryRow(ctx, query, shipmentId)
+	}
+
+	// Scan row to protobuf obj
+	shipment, err := scanRowToShipment(row)
+	if err != nil {
+		return nil, err
+	}
+
+	return shipment, nil
+}
+
+func (c postgresController) getShipmentByOrderId(ctx context.Context, tx *pgx.Tx, orderId string) (*pb.Shipment, error) {
+	// Determine if a db transaction is being used
+	var row pgx.Row
+	const query = pgShipmentBaseQuery + " WHERE order_id=$1"
+	if tx == nil {
+		row = c.cl.QueryRow(ctx, query, orderId)
+	} else {
+		row = (*tx).QueryRow(ctx, query, orderId)
+	}
+
+	// Scan row to protobuf obj
+	shipment, err := scanRowToShipment(row)
+	if err != nil {
+		return nil, err
+	}
+
+	return shipment, nil
+}
+
+func (c postgresController) GetShipmentItems(ctx context.Context, shipmentId string) ([]*pb.ShipmentItem, error) {
+	return c.getShipmentItems(ctx, nil, shipmentId)
+}
+
+func (c postgresController) getShipmentItems(ctx context.Context, tx *pgx.Tx, shipmentId string) ([]*pb.ShipmentItem, error) {
+	// Determine if transaction is being used
+	var rows pgx.Rows
+	var err error
+	if tx == nil {
+		rows, err = c.cl.Query(ctx, pgShipmentItemsBaseQuery+" WHERE shipment_id=$1", shipmentId)
+	} else {
+		rows, err = (*tx).Query(ctx, pgShipmentItemsBaseQuery+" WHERE shipment_id=$1", shipmentId)
+	}
+
+	if err != nil {
+		return nil, errors.WrapServiceError(errors.ErrCodeService, "query error whilst fetching items", err)
+	}
+
+	shipmentItems := []*pb.ShipmentItem{}
+	for rows.Next() {
+		var shipmentItem pb.ShipmentItem
+		shipmentItem.ShipmentId = shipmentId
+		err := rows.Scan(
+			&shipmentItem.ProductId,
+			&shipmentItem.Quantity,
+		)
+		if err != nil {
+			return nil, errors.WrapServiceError(errors.ErrCodeService, "failed to scan an order item", err)
+		}
+
+		shipmentItems = append(shipmentItems, &shipmentItem)
+	}
+
+	if rows.Err() != nil {
+		return nil, errors.WrapServiceError(errors.ErrCodeService, "error whilst scanning order item rows", rows.Err())
+	}
+
+	return shipmentItems, nil
+}
+
+func (c postgresController) AllocateOrderShipment(ctx context.Context, orderId string, orderMetadata shipping.EventOrderMetadata, productQuantities map[string]int32) error {
+	// Begin a DB transaction
+	tx, err := c.cl.Begin(ctx)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to begin transaction", err)
+	}
+	defer tx.Rollback(ctx)
+
+	// Create shipment
+	var shipmentId string
+	err = tx.QueryRow(ctx, "INSERT INTO shipments (order_id) VALUES ($1) RETURNING id", orderId).Scan(&shipmentId)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to create shipment", err)
+	}
+
+	// Add shipment items
+	vals := [][]interface{}{}
+	for productId, quantity := range productQuantities {
+		vals = append(
+			vals,
+			goqu.Vals{shipmentId, productId, quantity},
+		)
+	}
+
+	statement, args, err := goqu.Dialect("postgres").From("shipment_items").Insert().Cols("shipment_id", "product_id", "quantity").Vals(vals...).Prepared(true).ToSQL()
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeService, "failed to build statement", err)
+	}
+
+	_, err = tx.Exec(ctx, statement, args...)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to add shipment items", err)
+	}
+
+	// Prepare and append shipment allocated event to transaction
+	evt, evtTopic, err := shipping.PrepareShipmentAllocationEvent_Allocated(orderId, orderMetadata, shipmentId, productQuantities)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeService, "failed to create event", err)
+	}
+
+	_, err = tx.Exec(ctx, "INSERT INTO event_outbox (aggregateid, aggregatetype, payload) VALUES ($1, $2, $3)", shipmentId, evtTopic, evt)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to insert event", err)
+	}
+
+	// Commit the transaction
+	err = tx.Commit(ctx)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to commit transaction", err)
+	}
+
+	return nil
+}
+
+func (c postgresController) CancelOrderShipment(ctx context.Context, orderId string) error {
+	// Begin a DB transaction
+	tx, err := c.cl.Begin(ctx)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to begin transaction", err)
+	}
+	defer tx.Rollback(ctx)
+
+	// Get the shipment
+	shipment, err := c.getShipmentByOrderId(ctx, &tx, orderId)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to fetch shipment info", err)
+	}
+
+	// Get the shipment items
+	shipmentItems, err := c.getShipmentItems(ctx, &tx, shipment.Id)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to fetch shipment manifest", err)
+	}
+
+	// Delete shipment
+	_, err = tx.Exec(ctx, "DELETE FROM shipments WHERE id=$1", shipment.Id)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to delete shipment", err)
+	}
+
+	// Add the event to the outbox table with the transaction
+	evt, evtTopic, err := shipping.PrepareShipmentAllocationEvent_AllocationReleased(orderId, shipment.Id, shipmentItems)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeService, "failed to create event", err)
+	}
+
+	_, err = tx.Exec(ctx, "INSERT INTO event_outbox (aggregateid, aggregatetype, payload) VALUES ($1, $2, $3)", shipment.Id, evtTopic, evt)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to insert event", err)
+	}
+
+	// Commit the transaction
+	err = tx.Commit(ctx)
+	if err != nil {
+		return errors.WrapServiceError(errors.ErrCodeExtService, "failed to commit transaction", err)
+	}
+
+	return nil
+}
+
+// Scan a postgres row to a protobuf object
+func scanRowToShipment(row pgx.Row) (*pb.Shipment, error) {
+	var shipment pb.Shipment
+
+	// Temporary variables that require conversion
+	var tmpCreatedAt pgtype.Timestamp
+
+	err := row.Scan(
+		&shipment.Id,
+		&shipment.OrderId,
+		&shipment.Dispatched,
+		&tmpCreatedAt,
+	)
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return nil, errors.WrapServiceError(errors.ErrCodeNotFound, "shipment not found", err)
+		} else {
+			return nil, errors.WrapServiceError(errors.ErrCodeExtService, "something went wrong scanning object", err)
+		}
+	}
+
+	// convert postgres timestamps to unix format
+	if tmpCreatedAt.Valid {
+		shipment.CreatedAt = tmpCreatedAt.Time.Unix()
+	} else {
+		return nil, errors.NewServiceError(errors.ErrCodeUnknown, "something went wrong scanning object (timestamp conversion error)")
+	}
+
+	return &shipment, nil
+}

internal/svc/shipping/event.go

@@ -0,0 +1,97 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package shipping
+
+import (
+	"github.com/hexolan/stocklet/internal/pkg/messaging"
+	eventspb "github.com/hexolan/stocklet/internal/pkg/protogen/events/v1"
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+)
+
+type EventOrderMetadata struct {
+	CustomerId string
+	ItemsPrice float32
+	TotalPrice float32
+}
+
+func PrepareShipmentAllocationEvent_Failed(orderId string, orderMetadata EventOrderMetadata, productQuantities map[string]int32) ([]byte, string, error) {
+	topic := messaging.Shipping_Shipment_Allocation_Topic
+	event := &eventspb.ShipmentAllocationEvent{
+		Revision: 1,
+
+		Type:    eventspb.ShipmentAllocationEvent_TYPE_FAILED,
+		OrderId: orderId,
+		OrderMetadata: &eventspb.ShipmentAllocationEvent_OrderMetadata{
+			CustomerId: orderMetadata.CustomerId,
+			ItemsPrice: orderMetadata.ItemsPrice,
+			TotalPrice: orderMetadata.TotalPrice,
+		},
+		ProductQuantities: productQuantities,
+	}
+
+	return messaging.MarshalEvent(event, topic)
+}
+
+func PrepareShipmentAllocationEvent_Allocated(orderId string, orderMetadata EventOrderMetadata, shipmentId string, productQuantities map[string]int32) ([]byte, string, error) {
+	topic := messaging.Shipping_Shipment_Allocation_Topic
+	event := &eventspb.ShipmentAllocationEvent{
+		Revision: 1,
+
+		Type:    eventspb.ShipmentAllocationEvent_TYPE_ALLOCATED,
+		OrderId: orderId,
+		OrderMetadata: &eventspb.ShipmentAllocationEvent_OrderMetadata{
+			CustomerId: orderMetadata.CustomerId,
+			ItemsPrice: orderMetadata.ItemsPrice,
+			TotalPrice: orderMetadata.TotalPrice,
+		},
+		ShipmentId:        shipmentId,
+		ProductQuantities: productQuantities,
+	}
+
+	return messaging.MarshalEvent(event, topic)
+}
+
+func PrepareShipmentAllocationEvent_AllocationReleased(orderId string, shipmentId string, shipmentItems []*pb.ShipmentItem) ([]byte, string, error) {
+	productQuantities := make(map[string]int32)
+	for _, item := range shipmentItems {
+		productQuantities[item.ProductId] = item.Quantity
+	}
+
+	topic := messaging.Shipping_Shipment_Allocation_Topic
+	event := &eventspb.ShipmentAllocationEvent{
+		Revision: 1,
+
+		Type:              eventspb.ShipmentAllocationEvent_TYPE_ALLOCATION_RELEASED,
+		OrderId:           orderId,
+		ShipmentId:        shipmentId,
+		ProductQuantities: productQuantities,
+	}
+
+	return messaging.MarshalEvent(event, topic)
+}
+
+func PrepareShipmentDispatchedEvent(orderId string, shipmentId string, productQuantities map[string]int32) ([]byte, string, error) {
+	topic := messaging.Shipping_Shipment_Dispatched_Topic
+	event := &eventspb.ShipmentDispatchedEvent{
+		Revision: 1,
+
+		OrderId:           orderId,
+		ShipmentId:        shipmentId,
+		ProductQuantities: productQuantities,
+	}
+
+	return messaging.MarshalEvent(event, topic)
+}

internal/svc/shipping/shipping.go

@@ -0,0 +1,147 @@
+// Copyright (C) 2024 Declan Teevan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package shipping
+
+import (
+	"context"
+
+	"github.com/bufbuild/protovalidate-go"
+	"github.com/rs/zerolog/log"
+	"google.golang.org/protobuf/types/known/emptypb"
+
+	"github.com/hexolan/stocklet/internal/pkg/errors"
+	"github.com/hexolan/stocklet/internal/pkg/messaging"
+	commonpb "github.com/hexolan/stocklet/internal/pkg/protogen/common/v1"
+	eventpb "github.com/hexolan/stocklet/internal/pkg/protogen/events/v1"
+	pb "github.com/hexolan/stocklet/internal/pkg/protogen/shipping/v1"
+)
+
+// Interface for the service
+type ShippingService struct {
+	pb.UnimplementedShippingServiceServer
+
+	store StorageController
+	pbVal *protovalidate.Validator
+}
+
+// Interface for database methods
+// Flexibility for implementing seperate controllers for different databases (e.g. Postgres, MongoDB, etc)
+type StorageController interface {
+	GetShipment(ctx context.Context, shipmentId string) (*pb.Shipment, error)
+	GetShipmentItems(ctx context.Context, shipmentId string) ([]*pb.ShipmentItem, error)
+
+	AllocateOrderShipment(ctx context.Context, orderId string, orderMetadata EventOrderMetadata, productQuantities map[string]int32) error
+	CancelOrderShipment(ctx context.Context, orderId string) error
+}
+
+// Interface for event consumption
+// Flexibility for seperate controllers for different messaging systems (e.g. Kafka, NATS, etc)
+type ConsumerController interface {
+	messaging.ConsumerController
+
+	Attach(svc pb.ShippingServiceServer)
+}
+
+// Create the shipping service
+func NewShippingService(cfg *ServiceConfig, store StorageController) *ShippingService {
+	// Initialise the protobuf validator
+	pbVal, err := protovalidate.New()
+	if err != nil {
+		log.Panic().Err(err).Msg("failed to initialise protobuf validator")
+	}
+
+	// Initialise the service
+	return &ShippingService{
+		store: store,
+		pbVal: pbVal,
+	}
+}
+
+func (svc ShippingService) ServiceInfo(ctx context.Context, req *commonpb.ServiceInfoRequest) (*commonpb.ServiceInfoResponse, error) {
+	return &commonpb.ServiceInfoResponse{
+		Name:          "shipping",
+		Source:        "https://github.com/hexolan/stocklet",
+		SourceLicense: "AGPL-3.0",
+	}, nil
+}
+
+func (svc ShippingService) ViewShipment(ctx context.Context, req *pb.ViewShipmentRequest) (*pb.ViewShipmentResponse, error) {
+	// Validate the request args
+	if err := svc.pbVal.Validate(req); err != nil {
+		// Provide the validation error to the user.
+		return nil, errors.NewServiceError(errors.ErrCodeInvalidArgument, "invalid request: "+err.Error())
+	}
+
+	// todo: permission checking?
+
+	// Get shipment from DB
+	shipment, err := svc.store.GetShipment(ctx, req.ShipmentId)
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.ViewShipmentResponse{Shipment: shipment}, nil
+}
+
+func (svc ShippingService) ViewShipmentManifest(ctx context.Context, req *pb.ViewShipmentManifestRequest) (*pb.ViewShipmentManifestResponse, error) {
+	// Validate the request args
+	if err := svc.pbVal.Validate(req); err != nil {
+		// Provide the validation error to the user.
+		return nil, errors.NewServiceError(errors.ErrCodeInvalidArgument, "invalid request: "+err.Error())
+	}
+
+	// todo: permission checking?
+
+	shipmentItems, err := svc.store.GetShipmentItems(ctx, req.ShipmentId)
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.ViewShipmentManifestResponse{Manifest: shipmentItems}, nil
+}
+
+func (svc ShippingService) ProcessStockReservationEvent(ctx context.Context, req *eventpb.StockReservationEvent) (*emptypb.Empty, error) {
+	if req.Type == eventpb.StockReservationEvent_TYPE_STOCK_RESERVED {
+		err := svc.store.AllocateOrderShipment(
+			ctx,
+			req.OrderId,
+			EventOrderMetadata{
+				CustomerId: req.OrderMetadata.CustomerId,
+				ItemsPrice: req.OrderMetadata.ItemsPrice,
+				TotalPrice: req.OrderMetadata.TotalPrice,
+			},
+			req.ReservationStock,
+		)
+		if err != nil {
+			return nil, errors.WrapServiceError(errors.ErrCodeExtService, "failed to update in response to event", err)
+		}
+
+	}
+
+	return &emptypb.Empty{}, nil
+}
+
+func (svc ShippingService) ProcessPaymentProcessedEvent(ctx context.Context, req *eventpb.PaymentProcessedEvent) (*emptypb.Empty, error) {
+	if req.Type == eventpb.PaymentProcessedEvent_TYPE_FAILED {
+		err := svc.store.CancelOrderShipment(ctx, req.OrderId)
+		if err != nil {
+			return nil, errors.WrapServiceError(errors.ErrCodeExtService, "failed to update in response to event", err)
+		}
+
+	}
+
+	return &emptypb.Empty{}, nil
+}