feat(error): added first steps for custom errors

Signed-off-by: SoXX <soxx@fenpa.ws>

error/database.go

@@ -0,0 +1,19 @@
+package error
+
+type EntityAlreadyExists struct{}
+
+type NoDataWritten struct{}
+
+type NoDataFound struct{}
+
+func (e *EntityAlreadyExists) Error() string {
+	return "EntityAlreadyExists error"
+}
+
+func (e *NoDataWritten) Error() string {
+	return "NoDataWritten error"
+}
+
+func (e *NoDataFound) Error() string {
+	return "NoDataFound error"
+}

error/validation.go

@@ -0,0 +1,7 @@
+package error
+
+type MissingAnthrovePostIDError struct{}
+
+func (e *MissingAnthrovePostIDError) Error() string {
+	return "AnthrovePostID is empty"
+}

internal/postgres/post.go

@@ -3,16 +3,24 @@ package postgres
 import (
 	"context"
 	"errors"
-	"fmt"
+
+	error2 "git.dragse.it/anthrove/otter-space-sdk/error"
 	"git.dragse.it/anthrove/otter-space-sdk/pkg/models"
 	log "github.com/sirupsen/logrus"
 	"gorm.io/gorm"
 )
 
 func CreatePost(ctx context.Context, db *gorm.DB, anthrovePost *models.Post) error {
-	err := db.WithContext(ctx).Create(&anthrovePost).Error
-	if err != nil {
-		return err
+	result := db.WithContext(ctx).Create(&anthrovePost)
+
+	if result.RowsAffected == 0 {
+		return &error2.NoDataWritten{}
+	}
+
+	if result.Error != nil {
+		if errors.Is(result.Error, gorm.ErrDuplicatedKey) {
+			return &error2.EntityAlreadyExists{}
+		}
 	}
 
 	log.WithFields(log.Fields{
@@ -25,13 +33,15 @@ func CreatePost(ctx context.Context, db *gorm.DB, anthrovePost *models.Post) err
 
 func GetPostByAnthroveID(ctx context.Context, db *gorm.DB, anthrovePostID models.AnthrovePostID) (*models.Post, error) {
 	if anthrovePostID == "" {
-		return nil, fmt.Errorf("anthrovePostID is required")
+		return nil, &error2.MissingAnthrovePostIDError{}
 	}
 
 	var post models.Post
-	err := db.WithContext(ctx).First(&post, "id = ?", anthrovePostID).Error
-	if err != nil {
-		return nil, err
+	result := db.WithContext(ctx).First(&post, "id = ?", anthrovePostID)
+	if result.Error != nil {
+		if errors.Is(result.Error, gorm.ErrRecordNotFound) {
+			return nil, &error2.NoDataFound{}
+		}
 	}
 
 	return &post, nil