Separated graphql schema into multiple files and moved them to graph/schema dir, update the gqlgen.yml accordingly

Removed unnecesary bindings for ID and Int in gqlgen.yml
Minor changes to Makefile docker-clean target
Reduced docker-compose postgres healthcheck interval for faster local db connections
Added pagination to graphql schema, the paginated queries are WIP
Removed unneeded fields from the model structs
Added allowComment check when adding comments
Switched gorm logger to Info mode
App now panics if the specified APP_STORAGE in env doesn't exist
Reworked database methods, still barely working and are WIP

Makefile

@@ -13,4 +13,6 @@ go-generate:
 clean: docker-clean
 
 docker-clean:
-	docker container rm postgres-ozon-task-1 postgres-postgres-1 && docker volume rm postgres_postgres-data
+	-docker container rm postgres-ozon-task-1 postgres-postgres-1 standalone-ozon-task-1;\
+	docker volume rm postgres_postgres-data;\
+	docker network rm postgres_default standalone_defaul\

deployments/docker-compose/postgres/docker-compose.yml

@@ -13,7 +13,7 @@ services:
     env_file: postgres.env
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U $$POSTGRES_USER -d $$POSTGRES_DB"]
-      interval: 5s
+      interval: 1s
       timeout: 5s
       retries: 5
     volumes:

gqlgen.yml

@@ -1,6 +1,6 @@
 # Where are all the schema files located? globs are supported eg  src/**/*.graphqls
 schema:
-  - graph/*.graphqls
+  - graph/schema/*.graphqls
 
 # Where should the generated server code go?
 exec:
@@ -75,14 +75,6 @@ autobind:
 # your liking
 models:
   ID:
-    model:
-      - github.com/99designs/gqlgen/graphql.ID
-      - github.com/99designs/gqlgen/graphql.Int
-      - github.com/99designs/gqlgen/graphql.Int64
-      - github.com/99designs/gqlgen/graphql.Int32
-      - github.com/99designs/gqlgen/graphql.Uint
+    model: github.com/99designs/gqlgen/graphql.Uint
   Int:
-    model:
-      - github.com/99designs/gqlgen/graphql.Int
-      - github.com/99designs/gqlgen/graphql.Int64
-      - github.com/99designs/gqlgen/graphql.Int32
+    model: github.com/99designs/gqlgen/graphql.Int

graph/model/data.go

@@ -15,17 +15,9 @@ type Comment struct {
 	UpdatedAt time.Time
 	DeletedAt gorm.DeletedAt `gorm:"index"`
 
-	// db foreign key to reference parent post
-	PostID uint
-
-	Post     *Post  `json:"post"`
+	PostID   uint       `json:"post_id"`
 	Author   string     `json:"author"`
 	Contents string     `json:"contents"`
-
-	// db key to reference parent comment
-	ReplyToID *uint
-
-	ReplyTo *Comment   `json:"reply_to,omitempty"`
 	Replies  []*Comment `json:"replies" gorm:"many2many:comment_replies"`
 }
 
@@ -49,6 +41,7 @@ func PostFromInput(input *PostInput) *Post {
 		Title:         input.Title,
 		Contents:      input.Contents,
 		AllowComments: input.AllowComments,
+		Comments:      make([]*Comment, 0),
 	}
 }
 

graph/model/models_gen.go

@@ -2,8 +2,34 @@
 
 package model
 
+type CommentsConnection struct {
+	Edges    []*CommentsEdge `json:"edges"`
+	PageInfo *PageInfo       `json:"pageInfo"`
+}
+
+type CommentsEdge struct {
+	Cursor uint     `json:"cursor"`
+	Node   *Comment `json:"node"`
+}
+
 type Mutation struct {
 }
 
+type PageInfo struct {
+	StartCursor uint `json:"startCursor"`
+	EndCursor   uint `json:"endCursor"`
+	HasNextPage bool `json:"hasNextPage"`
+}
+
+type PostsConnection struct {
+	Edges    []*PostsEdge `json:"edges"`
+	PageInfo *PageInfo    `json:"pageInfo"`
+}
+
+type PostsEdge struct {
+	Cursor uint  `json:"cursor"`
+	Node   *Post `json:"node"`
+}
+
 type Query struct {
 }

graph/mutation.resolvers.go

@@ -12,31 +12,26 @@ import (
 )
 
 // AddPost is the resolver for the add_post field.
-func (r *mutationResolver) AddPost(ctx context.Context, input *model.PostInput) (*model.AddResult, error) {
-	return r.Storage.AddPost(input)
+func (r *mutationResolver) AddPost(ctx context.Context, input model.PostInput) (*model.AddResult, error) {
+	return r.Storage.AddPost(&input)
 }
 
 // AddComment is the resolver for the add_comment field.
-func (r *mutationResolver) AddComment(ctx context.Context, input *model.CommentInput) (*model.AddResult, error) {
+func (r *mutationResolver) AddComment(ctx context.Context, input model.CommentInput) (*model.AddResult, error) {
 	if len(input.Contents) > model.CommentLengthLimit {
 		return nil, fmt.Errorf("exceeded max comment length of %d chars", model.CommentLengthLimit)
 	}
-	if input.ParentCommentID == nil && input.ParentPostID == nil {
+	switch {
+	case input.ParentPostID != nil:
+		return r.Storage.AddCommentToPost(&input)
+	case input.ParentCommentID != nil:
+		return r.Storage.AddReplyToComment(&input)
+	default:
 		return nil, fmt.Errorf("parent post or parent comment ids weren't specified")
 	}
-	return r.Storage.AddComment(input)
-}
-
-// AllPosts is the resolver for the all_posts field.
-func (r *queryResolver) AllPosts(ctx context.Context) ([]*model.Post, error) {
-	return r.Storage.GetPosts()
 }
 
 // Mutation returns MutationResolver implementation.
 func (r *Resolver) Mutation() MutationResolver { return &mutationResolver{r} }
 
-// Query returns QueryResolver implementation.
-func (r *Resolver) Query() QueryResolver { return &queryResolver{r} }
-
 type mutationResolver struct{ *Resolver }
-type queryResolver struct{ *Resolver }

graph/query.resolvers.go

@@ -0,0 +1,49 @@
+package graph
+
+// This file will be automatically regenerated based on the schema, any resolver implementations
+// will be copied through when generating and any unknown code will be moved to the end.
+// Code generated by github.com/99designs/gqlgen version v0.17.49
+
+import (
+	"context"
+
+	"git.obamna.ru/erius/ozon-task/graph/model"
+)
+
+// Replies is the resolver for the replies field.
+func (r *commentResolver) Replies(ctx context.Context, obj *model.Comment, first uint, after uint) (*model.CommentsConnection, error) {
+	return r.Storage.GetReplies(obj, first, after, ctx)
+}
+
+// Comments is the resolver for the comments field.
+func (r *postResolver) Comments(ctx context.Context, obj *model.Post, first uint, after uint) (*model.CommentsConnection, error) {
+	return r.Storage.GetComments(obj, first, after, ctx)
+}
+
+// Post is the resolver for the post field.
+func (r *queryResolver) Post(ctx context.Context, id uint) (*model.Post, error) {
+	return r.Storage.GetPost(id, ctx)
+}
+
+// Posts is the resolver for the posts field.
+func (r *queryResolver) Posts(ctx context.Context, first uint, after uint) (*model.PostsConnection, error) {
+	return r.Storage.GetPosts(first, after, ctx)
+}
+
+// Comment is the resolver for the comment field.
+func (r *queryResolver) Comment(ctx context.Context, id uint) (*model.Comment, error) {
+	return r.Storage.GetComment(id, ctx)
+}
+
+// Comment returns CommentResolver implementation.
+func (r *Resolver) Comment() CommentResolver { return &commentResolver{r} }
+
+// Post returns PostResolver implementation.
+func (r *Resolver) Post() PostResolver { return &postResolver{r} }
+
+// Query returns QueryResolver implementation.
+func (r *Resolver) Query() QueryResolver { return &queryResolver{r} }
+
+type commentResolver struct{ *Resolver }
+type postResolver struct{ *Resolver }
+type queryResolver struct{ *Resolver }

graph/schema.graphqls

@@ -1,44 +0,0 @@
-type Post {
-  id: ID!
-  title: String!
-  author: String!
-  contents: String!
-  comments: [Comment!]!
-  allowComments: Boolean!
-}
-
-type Comment {
-  id: ID!
-  post: Post!
-  author: String!
-  contents: String!
-  replyTo: Comment
-  replies: [Comment!]!
-}
-
-type Query {
-  allPosts: [Post!]!
-}
-
-type Mutation {
-  addPost(input: PostInput): AddResult!
-  addComment(input: CommentInput): AddResult!
-}
-
-input PostInput {
-  title: String!
-  author: String!
-  contents: String!
-  allowComments: Boolean! = true
-}
-
-input CommentInput {
-  parentPostId: ID
-  parentCommentId: ID
-  author: String!
-  contents: String!
-}
-
-type AddResult {
-  itemId: ID!
-}

graph/schema/mutation.graphqls

@@ -0,0 +1,22 @@
+type Mutation {
+  addPost(input: PostInput!): AddResult!
+  addComment(input: CommentInput!): AddResult!
+}
+
+input PostInput {
+  title: String!
+  author: String!
+  contents: String!
+  allowComments: Boolean! = true
+}
+
+input CommentInput {
+  parentPostId: ID
+  parentCommentId: ID
+  author: String!
+  contents: String!
+}
+
+type AddResult {
+  itemId: ID!
+}

graph/schema/pagination.graphqls

@@ -0,0 +1,25 @@
+type PostsConnection {
+  edges: [PostsEdge!]!
+  pageInfo: PageInfo!
+}
+
+type CommentsConnection {
+  edges: [CommentsEdge!]!
+  pageInfo: PageInfo!
+}
+
+type PostsEdge {
+  cursor: ID!
+  node: Post!
+}
+
+type CommentsEdge {
+  cursor: ID!
+  node: Comment!
+}
+
+type PageInfo {
+  startCursor: ID!
+  endCursor: ID!
+  hasNextPage: Boolean!
+}

graph/schema/query.graphqls

@@ -0,0 +1,21 @@
+type Query {
+  post(id: ID!): Post!
+  posts(first: ID!, after: ID!): PostsConnection!
+  comment(id: ID!): Comment!
+}
+
+type Post {
+  id: ID!
+  title: String!
+  author: String!
+  contents: String!
+  comments(first: ID!, after: ID!): CommentsConnection!
+  allowComments: Boolean!
+}
+
+type Comment {
+  id: ID!
+  author: String!
+  contents: String!
+  replies(first: ID!, after: ID!): CommentsConnection!
+}

internal/storage/db/database.go

@@ -1,7 +1,12 @@
 package db
 
 import (
+	"context"
+	"fmt"
+	"log"
+
 	"git.obamna.ru/erius/ozon-task/graph/model"
+	"github.com/99designs/gqlgen/graphql"
 	"gorm.io/gorm"
 )
 
@@ -15,48 +20,64 @@ func (s *Database) AddPost(input *model.PostInput) (*model.AddResult, error) {
 	return &model.AddResult{ItemID: &post.ID}, err
 }
 
-func (s *Database) AddComment(input *model.CommentInput) (*model.AddResult, error) {
+func (s *Database) AddReplyToComment(input *model.CommentInput) (*model.AddResult, error) {
 	comment := model.CommentFromInput(input)
-	if input.ParentPostID == nil {
 	// multiple operations performed in one transaction
 	err := s.db.Transaction(func(tx *gorm.DB) error {
-			var parent model.Comment
-			// find parent comment in db
-			err := s.db.First(&parent, *input.ParentCommentID).Error
-			if err != nil {
-				return err
-			}
-			// set new comment fields to reference parent post and comment
-			comment.ReplyTo = &parent
-			comment.PostID = parent.PostID
 		// insert comment
-			err = s.db.Create(comment).Error
+		err := s.db.Create(comment).Error
 		if err != nil {
 			return err
 		}
-			// add new reply to parent and save
-			parent.Replies = append(parent.Replies, comment)
-			err = s.db.Save(parent).Error
+		// add new reply to parent
+		err = s.db.Table("comment_replies").Create(map[string]interface{}{
+			"comment_id": *input.ParentCommentID,
+			"reply_id":   comment.ID,
+		}).Error
 		if err != nil {
 			return err
 		}
 		return nil
 	})
-		if err != nil {
-			return nil, err
-		}
-	} else {
-		comment.PostID = *input.ParentPostID
-		err := s.db.Create(comment).Error
-		if err != nil {
-			return nil, err
-		}
-	}
-	return &model.AddResult{ItemID: &comment.ID}, nil
+	return &model.AddResult{ItemID: &comment.ID}, err
 }
 
-func (s Database) GetPosts() ([]*model.Post, error) {
-	var posts []*model.Post
-	err := s.db.Find(&posts).Error
-	return posts, err
+func (s *Database) AddCommentToPost(input *model.CommentInput) (*model.AddResult, error) {
+	comment := model.CommentFromInput(input)
+	var allowComments bool
+	err := s.db.Table("posts").Select("allow_comments").Where("id = ?", *input.ParentPostID).Scan(&allowComments).Error
+	if err != nil {
+		return nil, err
+	}
+	if !allowComments {
+		return nil, fmt.Errorf("author disabled comments for this post")
+	}
+	err = s.db.Create(comment).Error
+	return &model.AddResult{ItemID: &comment.ID}, err
+}
+
+func (s *Database) GetPost(id uint, ctx context.Context) (*model.Post, error) {
+	log.Println(graphql.CollectAllFields(ctx))
+	log.Println(graphql.CollectFieldsCtx(ctx, nil))
+	var post model.Post
+	err := s.db.Find(&post, id).Error
+	return &post, err
+}
+
+func (s *Database) GetComment(id uint, ctx context.Context) (*model.Comment, error) {
+	var comment model.Comment
+	err := s.db.Find(&comment, id).Error
+	return &comment, err
+}
+
+func (s *Database) GetPosts(first uint, after uint, ctx context.Context) (*model.PostsConnection, error) {
+	return nil, nil
+}
+
+func (s *Database) GetComments(post *model.Post, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error) {
+	return nil, nil
+}
+
+func (s *Database) GetReplies(comment *model.Comment, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error) {
+	return nil, nil
 }

internal/storage/db/postgres.go

@@ -8,6 +8,7 @@ import (
 	"git.obamna.ru/erius/ozon-task/graph/model"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
 )
 
 var (
@@ -22,7 +23,10 @@ var (
 func InitPostgres() (*Database, error) {
 	log.Printf("connecting to PostgreSQL database at %s...", con)
 	// PrepareStmt is true for caching complex sql statements when adding comments or replies
-	db, err := gorm.Open(postgres.Open(con), &gorm.Config{PrepareStmt: true})
+	db, err := gorm.Open(postgres.Open(con), &gorm.Config{
+		PrepareStmt: true,
+		Logger:      logger.Default.LogMode(logger.Info),
+	})
 	if err != nil {
 		log.Printf("failed to connect to database: %s", err)
 		return nil, err

internal/storage/memory.go

@@ -1,6 +1,9 @@
 package storage
 
 import (
+	"context"
+	"fmt"
+
 	"git.obamna.ru/erius/ozon-task/graph/model"
 )
 
@@ -22,20 +25,142 @@ func InitInMemory() *InMemory {
 
 func (s *InMemory) AddPost(input *model.PostInput) (*model.AddResult, error) {
 	post := model.PostFromInput(input)
-	post.ID = s.postId
-	s.posts = append(s.posts, post)
-	s.postId++
+	s.insertPost(post)
 	return &model.AddResult{ItemID: &post.ID}, nil
 }
 
-func (s *InMemory) AddComment(input *model.CommentInput) (*model.AddResult, error) {
-	comment := model.CommentFromInput(input)
-	comment.ID = s.commentId
-	s.comments = append(s.comments, comment)
-	s.commentId++
+func (s *InMemory) AddReplyToComment(input *model.CommentInput) (*model.AddResult, error) {
+	if !s.commentExists(*input.ParentCommentID) {
+		return nil, &IDNotFoundError{objName: "comment", id: *input.ParentCommentID}
+	}
+	comment, parent := model.CommentFromInput(input), s.comments[*input.ParentCommentID]
+	s.insertComment(comment)
+	parent.Replies = append(parent.Replies, comment)
 	return &model.AddResult{ItemID: &comment.ID}, nil
 }
 
-func (s InMemory) GetPosts() ([]*model.Post, error) {
-	return s.posts, nil
+func (s *InMemory) AddCommentToPost(input *model.CommentInput) (*model.AddResult, error) {
+	if !s.postExists(*input.ParentPostID) {
+		return nil, &IDNotFoundError{objName: "post", id: *input.ParentPostID}
+	}
+	parent := s.posts[*input.ParentPostID]
+	if !parent.AllowComments {
+		return nil, fmt.Errorf("author disabled comments for this post")
+	}
+	comment := model.CommentFromInput(input)
+	s.insertComment(comment)
+	parent.Comments = append(parent.Comments, comment)
+	return &model.AddResult{ItemID: &comment.ID}, nil
+}
+
+func (s *InMemory) GetPost(id uint, ctx context.Context) (*model.Post, error) {
+	if !s.postExists(id) {
+		return nil, &IDNotFoundError{objName: "post", id: id}
+	}
+	return s.posts[id], nil
+}
+
+func (s *InMemory) GetComment(id uint, ctx context.Context) (*model.Comment, error) {
+	if !s.commentExists(id) {
+		return nil, &IDNotFoundError{objName: "comment", id: id}
+	}
+	return s.comments[id], nil
+}
+
+func (s *InMemory) GetPosts(first uint, after uint, ctx context.Context) (*model.PostsConnection, error) {
+	if !s.postExists(after) {
+		return nil, &IDNotFoundError{objName: "post", id: after}
+	}
+	nextPage, until := true, after+first
+	if !s.postExists(until) {
+		nextPage = false
+		until = uint(len(s.posts))
+	}
+	info, edges := &model.PageInfo{
+		StartCursor: after,
+		EndCursor:   until - 1,
+		HasNextPage: nextPage,
+	}, make([]*model.PostsEdge, until-after)
+	for i, p := range s.posts[after:until] {
+		edges[i] = &model.PostsEdge{
+			Cursor: p.ID,
+			Node:   p,
+		}
+	}
+	return &model.PostsConnection{
+		Edges:    edges,
+		PageInfo: info,
+	}, nil
+}
+
+func (s *InMemory) GetComments(post *model.Post, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error) {
+	if !s.commentExists(after) {
+		return nil, &IDNotFoundError{objName: "comment", id: after}
+	}
+	nextPage, until := true, after+first
+	if !s.commentExists(until) {
+		nextPage = false
+		until = uint(len(s.comments))
+	}
+	info, edges := &model.PageInfo{
+		StartCursor: after,
+		EndCursor:   until - 1,
+		HasNextPage: nextPage,
+	}, make([]*model.CommentsEdge, until-after)
+	for i, c := range post.Comments[after:until] {
+		edges[i] = &model.CommentsEdge{
+			Cursor: c.ID,
+			Node:   c,
+		}
+	}
+	return &model.CommentsConnection{
+		Edges:    edges,
+		PageInfo: info,
+	}, nil
+}
+
+func (s *InMemory) GetReplies(comment *model.Comment, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error) {
+	if !s.commentExists(after) {
+		return nil, &IDNotFoundError{objName: "comment", id: after}
+	}
+	nextPage, until := true, after+first
+	if !s.commentExists(until) {
+		nextPage = false
+		until = uint(len(s.comments))
+	}
+	info, edges := &model.PageInfo{
+		StartCursor: after,
+		EndCursor:   until - 1,
+		HasNextPage: nextPage,
+	}, make([]*model.CommentsEdge, until-after)
+	for i, c := range comment.Replies[after:until] {
+		edges[i] = &model.CommentsEdge{
+			Cursor: c.ID,
+			Node:   c,
+		}
+	}
+	return &model.CommentsConnection{
+		Edges:    edges,
+		PageInfo: info,
+	}, nil
+}
+
+func (s *InMemory) postExists(id uint) bool {
+	return id < uint(len(s.posts))
+}
+
+func (s *InMemory) commentExists(id uint) bool {
+	return id < uint(len(s.comments))
+}
+
+func (s *InMemory) insertComment(comment *model.Comment) {
+	comment.ID = s.commentId
+	s.comments = append(s.comments, comment)
+	s.commentId++
+}
+
+func (s *InMemory) insertPost(post *model.Post) {
+	post.ID = s.postId
+	s.posts = append(s.posts, post)
+	s.postId++
 }

internal/storage/storage.go

@@ -1,6 +1,8 @@
 package storage
 
 import (
+	"context"
+	"fmt"
 	"log"
 	"os"
 
@@ -8,20 +10,47 @@ import (
 	"git.obamna.ru/erius/ozon-task/internal/storage/db"
 )
 
+type IDNotFoundError struct {
+	objName string
+	id      uint
+}
+
+func (e *IDNotFoundError) Error() string {
+	return fmt.Sprintf("%s with id %d doesn't exist", e.objName, e.id)
+}
+
+// storage types enum
 const (
 	inMemory = "inmemory"
 	postgres = "postgres"
 )
 
-var storage = os.Getenv("APP_STORAGE")
+var storage, storageSpecified = os.LookupEnv("APP_STORAGE")
 
 type Storage interface {
 	AddPost(input *model.PostInput) (*model.AddResult, error)
-	AddComment(input *model.CommentInput) (*model.AddResult, error)
-	GetPosts() ([]*model.Post, error)
+
+	// assumes that input.ParentCommentID is not nil
+	AddReplyToComment(input *model.CommentInput) (*model.AddResult, error)
+
+	// assumes that input.ParentPostID is not nil
+	AddCommentToPost(input *model.CommentInput) (*model.AddResult, error)
+
+	// passing query context to analyze requested fields and prevent overfetching
+	GetPost(id uint, ctx context.Context) (*model.Post, error)
+	GetComment(id uint, ctx context.Context) (*model.Comment, error)
+
+	// returns paginated data in the form of model.*Connection (passing context to prevent overfetching)
+	GetPosts(first uint, after uint, ctx context.Context) (*model.PostsConnection, error)
+	GetComments(post *model.Post, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error)
+	GetReplies(comment *model.Comment, first uint, after uint, ctx context.Context) (*model.CommentsConnection, error)
 }
 
 func InitStorage() (Storage, error) {
+	if !storageSpecified {
+		log.Println("APP_STORAGE isn't specified, falling back to default in-memory storage", storage)
+		return InitInMemory(), nil
+	}
 	log.Printf("initializing storage of type %s...", storage)
 	switch storage {
 	case inMemory:
@@ -29,7 +58,6 @@ func InitStorage() (Storage, error) {
 	case postgres:
 		return db.InitPostgres()
 	default:
-		log.Printf("storage of type %s doesn't exists, falling back to default in-memory storage", storage)
-		return InitInMemory(), nil
+		return nil, fmt.Errorf("storage of type %s doesn't exists, change the value of APP_STORAGE env variable", storage)
 	}
 }