init post-service

services/post-service/internal/redis/post.go

@@ -0,0 +1,151 @@
+package redis
+
+import (
+	"time"
+	"context"
+	"encoding/json"
+
+	"github.com/rs/zerolog/log"
+	"github.com/redis/go-redis/v9"
+
+	"github.com/hexolan/panels/post-service/internal"
+)
+
+type postCacheRepo struct {
+	rdb *redis.Client
+
+	repo internal.PostRepository
+}
+
+func NewPostRepository(rdb *redis.Client, repo internal.PostRepository) internal.PostRepository {
+	return postCacheRepo{
+		rdb: rdb,
+		repo: repo,
+	}
+}
+
+func (r postCacheRepo) getCachedPost(ctx context.Context, id internal.PostId) *internal.Post {
+	value, err := r.rdb.Get(ctx, id.GetReprId()).Result()
+	if err == redis.Nil {
+		return nil
+	} else if err != nil {
+		log.Error().Err(err).Msg("failed to get cached post")
+		return nil
+	}
+
+	var post internal.Post
+	err = json.Unmarshal([]byte(value), &post)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to unmarshal cached post")
+		return nil
+	}
+
+	return &post
+}
+
+func (r postCacheRepo) cachePost(ctx context.Context, post *internal.Post) {
+	value, err := json.Marshal(post)
+	if err != nil {
+		log.Error().Err(err).Msg("failed to marshal post for caching")
+		return
+	}
+
+	err = r.rdb.Set(ctx, post.Id.GetReprId(), string(value), 2 * time.Minute).Err()
+	if err != nil {
+		log.Error().Err(err).Msg("failed to cache post")
+		return
+	}
+}
+
+func (r postCacheRepo) purgeCachedPost(ctx context.Context, id internal.PostId) {
+	err := r.rdb.Del(ctx, id.GetReprId()).Err()
+	if err != nil && err != redis.Nil {
+		log.Error().Err(err).Msg("error while purging cached post")
+	}
+}
+
+func (r postCacheRepo) CreatePost(ctx context.Context, panelId string, authorId string, data internal.PostCreate) (*internal.Post, error) {
+	// Create the post (using downstream DB repo)
+	post, err := r.repo.CreatePost(ctx, panelId, authorId, data)
+	if err != nil {
+		return post, err
+	}
+
+	// Cache and return the created post.
+	r.cachePost(ctx, post)
+	return post, err
+}
+
+func (r postCacheRepo) GetPost(ctx context.Context, id internal.PostId) (*internal.Post, error) {
+	// Check for a cached version of the post
+	if post := r.getCachedPost(ctx, id); post != nil {
+		return post, nil
+	}
+
+	// Post is not cached (fetch from DB)
+	post, err := r.repo.GetPost(ctx, id)
+	if err != nil {
+		return post, err
+	}
+
+	// Cache and return the fetched post
+	r.cachePost(ctx, post)
+	return post, err
+}
+
+func (r postCacheRepo) GetPanelPost(ctx context.Context, id internal.PostId, panelId string) (*internal.Post, error) {
+	// Check for a cached version of the post
+	if post := r.getCachedPost(ctx, id); post != nil {
+		// The post is cached. Ensure panelId is a match.
+		if post.PanelId != panelId {
+			return nil, internal.NewServiceError(internal.NotFoundErrorCode, "post not found on that panel")
+		}
+		return post, nil
+	}
+
+	// Post is not cached (fetch from DB)
+	post, err := r.repo.GetPanelPost(ctx, id, panelId)
+	if err != nil {
+		return post, err
+	}
+
+	// Cache and return the fetched post
+	r.cachePost(ctx, post)
+	return post, err
+}
+
+func (r postCacheRepo) UpdatePost(ctx context.Context, id internal.PostId, data internal.PostUpdate) (*internal.Post, error) {
+	// Update the post at the downstream repo.
+	post, err := r.repo.UpdatePost(ctx, id, data)
+	if err != nil {
+		return post, err
+	}
+
+	// Cache and return the updated post.
+	r.cachePost(ctx, post)
+	return post, err
+}
+
+func (r postCacheRepo) DeletePost(ctx context.Context, id internal.PostId) error {
+	// Delete the post downstream.
+	err := r.repo.DeletePost(ctx, id)
+	if err != nil {
+		return err
+	}
+
+	// Purge any cached version of the post.
+	r.purgeCachedPost(ctx, id)
+	return err
+}
+
+func (r postCacheRepo) GetFeedPosts(ctx context.Context) ([]*internal.Post, error) {
+	return r.repo.GetFeedPosts(ctx)
+}
+
+func (r postCacheRepo) GetUserPosts(ctx context.Context, userId string) ([]*internal.Post, error) {
+	return r.repo.GetUserPosts(ctx, userId)
+}
+
+func (r postCacheRepo) GetPanelPosts(ctx context.Context, panelId string) ([]*internal.Post, error) {
+	return r.repo.GetPanelPosts(ctx, panelId)
+}