[GitHub] [beam] damondouglas commented on a change in pull request #15721: [BEAM-13023][Playground] Implement Redis cache for pipelines' states

[GitBox <gi...@apache.org>]

damondouglas commented on a change in pull request #15721:
URL: https://github.com/apache/beam/pull/15721#discussion_r729889130



##########
File path: playground/backend/internal/cache/redis_cache.go
##########
@@ -0,0 +1,145 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	pb "beam.apache.org/playground/backend/internal/api"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"google.golang.org/grpc/grpclog"
+	"time"
+)
+
+const defaultExpirationTime = time.Minute * 15
+
+type RedisCache struct {
+	redisClient *redis.Client

Review comment:
       What if we did this pattern?  The outcome is that all the methods available to `redis.Client` are automatically bound to our struct but we can also bind our own new methods.  It was one of the rare occurences for me personally where I found value in this extends-like pattern in go.
   
   ```
   type RedisCache struct {
      *redis.Client
   }
   ```

##########
File path: playground/backend/internal/cache/redis_cache.go
##########
@@ -0,0 +1,145 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	pb "beam.apache.org/playground/backend/internal/api"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"google.golang.org/grpc/grpclog"
+	"time"
+)
+
+const defaultExpirationTime = time.Minute * 15
+
+type RedisCache struct {
+	redisClient *redis.Client
+}
+
+// check connection to Redis
+var ping = func(redisClient *redis.Client, ctx context.Context) (string, error) {

Review comment:
       These methods were challenging for me to read.  My comment is applied to `ping` but it applies to `exists`, `expire`, etc.  May we consider either binding the methods or doing the "extend" pattern commented above?

##########
File path: playground/backend/internal/cache/redis_cache.go
##########
@@ -0,0 +1,145 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	pb "beam.apache.org/playground/backend/internal/api"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"google.golang.org/grpc/grpclog"
+	"time"
+)
+
+const defaultExpirationTime = time.Minute * 15
+
+type RedisCache struct {
+	redisClient *redis.Client
+}
+
+// check connection to Redis
+var ping = func(redisClient *redis.Client, ctx context.Context) (string, error) {
+	return redisClient.Ping(ctx).Result()
+}
+
+// check if pipelineId exists as Redis key
+var exists = func(redisClient *redis.Client, ctx context.Context, pipelineId uuid.UUID) (int64, error) {
+	return redisClient.Exists(ctx, pipelineId.String()).Result()
+}
+
+// set expiration time for key
+var expire = func(redisClient *redis.Client, ctx context.Context, key string, expTime time.Duration) (bool, error) {
+	return redisClient.Expire(ctx, key, expTime).Result()
+}
+
+// put encoded value to {key}:{encoded subKey} structure
+var hSet = func(redisClient *redis.Client, ctx context.Context, key string, subKeyMarsh, valueMarsh []byte) (int64, error) {
+	return redisClient.HSet(ctx, key, subKeyMarsh, valueMarsh).Result()
+}
+
+// receive value from {key}:{subKey} structure
+var hGet = func(redisClient *redis.Client, ctx context.Context, key, subKey string) (string, error) {
+	return redisClient.HGet(ctx, key, subKey).Result()
+}
+
+// newRedisCache returns Redis implementation of Cache interface.
+// In case of problem with connection to Redis returns error.
+func newRedisCache(ctx context.Context, addr string) (*RedisCache, error) {

Review comment:
       How would a user of this package instantiate `RedisCache` if this is not public?  Also this constructor seems more restrictive than the original redis client.

##########
File path: playground/backend/internal/cache/redis_cache.go
##########
@@ -0,0 +1,145 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	pb "beam.apache.org/playground/backend/internal/api"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"google.golang.org/grpc/grpclog"
+	"time"
+)
+
+const defaultExpirationTime = time.Minute * 15
+
+type RedisCache struct {
+	redisClient *redis.Client
+}
+
+// check connection to Redis
+var ping = func(redisClient *redis.Client, ctx context.Context) (string, error) {
+	return redisClient.Ping(ctx).Result()
+}
+
+// check if pipelineId exists as Redis key
+var exists = func(redisClient *redis.Client, ctx context.Context, pipelineId uuid.UUID) (int64, error) {
+	return redisClient.Exists(ctx, pipelineId.String()).Result()
+}
+
+// set expiration time for key
+var expire = func(redisClient *redis.Client, ctx context.Context, key string, expTime time.Duration) (bool, error) {
+	return redisClient.Expire(ctx, key, expTime).Result()
+}
+
+// put encoded value to {key}:{encoded subKey} structure
+var hSet = func(redisClient *redis.Client, ctx context.Context, key string, subKeyMarsh, valueMarsh []byte) (int64, error) {
+	return redisClient.HSet(ctx, key, subKeyMarsh, valueMarsh).Result()
+}
+
+// receive value from {key}:{subKey} structure
+var hGet = func(redisClient *redis.Client, ctx context.Context, key, subKey string) (string, error) {
+	return redisClient.HGet(ctx, key, subKey).Result()
+}
+
+// newRedisCache returns Redis implementation of Cache interface.
+// In case of problem with connection to Redis returns error.
+func newRedisCache(ctx context.Context, addr string) (*RedisCache, error) {
+	rc := RedisCache{redisClient: redis.NewClient(&redis.Options{Addr: addr})}
+	_, err := ping(rc.redisClient, ctx)
+	if err != nil {
+		grpclog.Errorf("Redis Cache: connect to Redis: error during Ping operation, err: %s", err.Error())
+		return nil, err
+	}
+	return &rc, nil
+}
+
+func (rc *RedisCache) GetValue(ctx context.Context, pipelineId uuid.UUID, subKey SubKey) (interface{}, error) {
+	marshSubKey, err := json.Marshal(subKey)
+	if err != nil {
+		grpclog.Errorf("Redis Cache: get value: error during marshal subKey: %s, err: %s", subKey, err.Error())
+		return nil, err
+	}
+	value, err := hGet(rc.redisClient, ctx, pipelineId.String(), string(marshSubKey))
+	if err != nil {
+		grpclog.Errorf("Redis Cache: get value: error during HGet operation for key: %s, subKey: %s, err: %s", pipelineId.String(), subKey, err.Error())
+		return nil, err
+	}
+
+	return unmarshalBySubKey(subKey, value)
+}
+
+func (rc *RedisCache) SetValue(ctx context.Context, pipelineId uuid.UUID, subKey SubKey, value interface{}) error {
+	subKeyMarsh, err := json.Marshal(subKey)
+	if err != nil {
+		grpclog.Errorf("Redis Cache: set value: error during marshal subKey: %s, err: %s", subKey, err.Error())

Review comment:
       May we consider just using the `log` library native to go?

##########
File path: playground/backend/internal/cache/redis_cache.go
##########
@@ -0,0 +1,145 @@
+// Licensed to the Apache Software Foundation (ASF) under one or more
+// contributor license agreements.  See the NOTICE file distributed with
+// this work for additional information regarding copyright ownership.
+// The ASF licenses this file to You under the Apache License, Version 2.0
+// (the "License"); you may not use this file except in compliance with
+// the License.  You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package cache
+
+import (
+	pb "beam.apache.org/playground/backend/internal/api"
+	"context"
+	"encoding/json"
+	"fmt"
+	"github.com/go-redis/redis/v8"
+	"github.com/google/uuid"
+	"google.golang.org/grpc/grpclog"
+	"time"
+)
+
+const defaultExpirationTime = time.Minute * 15
+
+type RedisCache struct {
+	redisClient *redis.Client
+}
+
+// check connection to Redis
+var ping = func(redisClient *redis.Client, ctx context.Context) (string, error) {
+	return redisClient.Ping(ctx).Result()
+}
+
+// check if pipelineId exists as Redis key
+var exists = func(redisClient *redis.Client, ctx context.Context, pipelineId uuid.UUID) (int64, error) {
+	return redisClient.Exists(ctx, pipelineId.String()).Result()
+}
+
+// set expiration time for key
+var expire = func(redisClient *redis.Client, ctx context.Context, key string, expTime time.Duration) (bool, error) {
+	return redisClient.Expire(ctx, key, expTime).Result()
+}
+
+// put encoded value to {key}:{encoded subKey} structure
+var hSet = func(redisClient *redis.Client, ctx context.Context, key string, subKeyMarsh, valueMarsh []byte) (int64, error) {
+	return redisClient.HSet(ctx, key, subKeyMarsh, valueMarsh).Result()
+}
+
+// receive value from {key}:{subKey} structure
+var hGet = func(redisClient *redis.Client, ctx context.Context, key, subKey string) (string, error) {
+	return redisClient.HGet(ctx, key, subKey).Result()
+}
+
+// newRedisCache returns Redis implementation of Cache interface.
+// In case of problem with connection to Redis returns error.
+func newRedisCache(ctx context.Context, addr string) (*RedisCache, error) {

Review comment:
       I now see with https://github.com/apache/beam/pull/15714/files#diff-c9958b6146b1d7a3cc749646a8807db23e6d2d35bd44ab0b3fb775d6b445e64fR48 how this is intended to be used.  Perhaps then it makes sense to not make `RedisCache` public.




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