Added method to get keys by prefix

Signed-off-by: knrt10 <tripathi.kautilya@gmail.com>

api/server/api.go

@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	"strings"
 	"time"
 
 	"github.com/golang/protobuf/ptypes/empty"
@@ -52,6 +53,38 @@ func (c *cache) Get(ctx context.Context, args *api.GetKey) (*api.Item, error) {
 	}, nil
 }
 
+// GetByPrefix method is all keys that match the prefix while providing key as args
+func (c *cache) GetByPrefix(ctx context.Context, args *api.GetKey) (*api.AllItems, error) {
+	key := args.Key
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	var items []*api.Item
+	now := time.Now().UnixNano()
+	for k, v := range c.items {
+		if v.(Item).Expiration > 0 {
+			if now > v.(Item).Expiration {
+				continue
+			}
+		}
+
+		if strings.Contains(k.(string), key) {
+			items = append(items, &api.Item{
+				Key:        k.(string),
+				Value:      v.(Item).Object.(string),
+				Expiration: time.Unix(0, v.(Item).Expiration).String(),
+			})
+		}
+	}
+	// This means no keys were found, or all were expired
+	if len(items) < 1 {
+		return nil, ErrNoKey
+	}
+
+	return &api.AllItems{
+		Items: items,
+	}, nil
+}
+
 // GetAllItems method get all unexpired keys from the cache
 func (c *cache) GetAllItems(ctx context.Context, in *empty.Empty) (*api.AllItems, error) {
 	c.mu.RLock()

api/server/api_test.go

@@ -113,7 +113,7 @@ func TestGet(t *testing.T) {
 	}
 	resp, err := c.Get(context.Background(), keyGet)
 	if err != nil {
-		t.Fatalf("Adding key Failed: %v", err)
+		t.Fatalf("Getting key Failed: %v", err)
 	}
 	if resp.Key != "kautilya" {
 		t.Errorf("handler returned unexpected body: got %v want %v",
@@ -125,6 +125,59 @@ func TestGet(t *testing.T) {
 	}
 }
 
+func TestGetByPrefix(t *testing.T) {
+	ctx := context.Background()
+	conn, err := grpc.DialContext(ctx, "bufnet", grpc.WithContextDialer(bufDialer), grpc.WithInsecure())
+	if err != nil {
+		t.Fatalf("Failed to dial bufnet: %v", err)
+	}
+	defer conn.Close()
+	c := apis.NewCacheServiceClient(conn)
+
+	keyVal1 := &apis.Item{
+		Key:        "prefixTest",
+		Value:      "val1",
+		Expiration: "10s",
+	}
+
+	keyVal2 := &apis.Item{
+		Key:        "prefixTest1",
+		Value:      "val2",
+		Expiration: "10s",
+	}
+
+	keyVal3 := &apis.Item{
+		Key:        "prefixTest2",
+		Value:      "val3",
+		Expiration: "10s",
+	}
+
+	c.Add(context.Background(), keyVal1)
+	c.Add(context.Background(), keyVal2)
+	c.Add(context.Background(), keyVal3)
+
+	keyWrongPrefix := &apis.GetKey{
+		Key: "wrongPrefix",
+	}
+	_, err = c.GetByPrefix(context.Background(), keyWrongPrefix)
+	if err.Error() != "rpc error: code = Unknown desc = No key found" {
+		t.Errorf("No key found")
+	}
+
+	keyRightPrefix := &apis.GetKey{
+		Key: "prefixTest",
+	}
+
+	resp, err := c.GetByPrefix(context.Background(), keyRightPrefix)
+	if err != nil {
+		t.Fatalf("Getting key by prefix Failed: %v", err)
+	}
+	if len(resp.Items) != 3 {
+		t.Errorf("handler returned unexpected body: got %v want %v",
+			len(resp.Items), 3)
+	}
+}
+
 func TestGetAllItems(t *testing.T) {
 	ctx := context.Background()
 	conn, err := grpc.DialContext(ctx, "bufnet", grpc.WithContextDialer(bufDialer), grpc.WithInsecure())
@@ -136,7 +189,7 @@ func TestGetAllItems(t *testing.T) {
 
 	_, err = c.GetAllItems(context.Background(), &empty.Empty{})
 	if err != nil {
-		t.Fatalf("Adding key Failed: %v", err)
+		t.Fatalf("Getting all keys Failed: %v", err)
 	}
 }
 
@@ -154,7 +207,7 @@ func TestDeleteKey(t *testing.T) {
 	}
 	resp, err := c.DeleteKey(context.Background(), keyGet)
 	if err != nil {
-		t.Fatalf("Adding key Failed: %v", err)
+		t.Fatalf("Deleting key Failed: %v", err)
 	}
 	if resp.Success != true {
 		t.Errorf("handler returned unexpected body: got %v want %v",
@@ -173,7 +226,7 @@ func TestDeleteAll(t *testing.T) {
 
 	resp, err := c.DeleteAll(context.Background(), &empty.Empty{})
 	if err != nil {
-		t.Fatalf("Adding key Failed: %v", err)
+		t.Fatalf("Deleting key Failed: %v", err)
 	}
 	if resp.Success != true {
 		t.Errorf("handler returned unexpected body: got %v want %v",

examples/client.go

@@ -51,8 +51,29 @@ func main() {
 		Expiration: "2min10s",
 	}
 
+	keyVal4 := &api.Item{
+		Key:        "prefixTest",
+		Value:      "val1",
+		Expiration: "10s",
+	}
+
+	keyVal5 := &api.Item{
+		Key:        "prefixTest1",
+		Value:      "val2",
+		Expiration: "10s",
+	}
+
+	keyVal6 := &api.Item{
+		Key:        "prefixTest2",
+		Value:      "val3",
+		Expiration: "10s",
+	}
+
 	c.Add(context.Background(), keyVal1)
 	c.Add(context.Background(), keyVal2)
+	c.Add(context.Background(), keyVal4)
+	c.Add(context.Background(), keyVal5)
+	c.Add(context.Background(), keyVal6)
 
 	addKeyRes, err := c.Add(context.Background(), keyVal3)
 	if err != nil {
@@ -80,6 +101,17 @@ func main() {
 	}
 	fmt.Println("Response from server for getting a key", getKeyRes)
 
+	// Get keys by prefix
+	keyGetPrefix := &api.GetKey{
+		Key: "prefixTest",
+	}
+
+	getKeyPrefixRes, err := c.GetByPrefix(context.Background(), keyGetPrefix)
+	if err != nil {
+		log.Fatalf("Error when calling Get: %s", err)
+	}
+	fmt.Println("Response from server for getting a keys by prefix", getKeyPrefixRes)
+
 	// GetAllItems
 	getAllKeysRes, err := c.GetAllItems(context.Background(), &empty.Empty{})
 	if err != nil {

proto/cache-service.proto

@@ -26,6 +26,7 @@ message Success {
 service CacheService {
     rpc Add (Item) returns (Item);
     rpc Get (GetKey) returns (Item);
+    rpc GetByPrefix(GetKey) returns (AllItems);
     rpc GetAllItems(google.protobuf.Empty) returns (AllItems);
     rpc DeleteKey(GetKey) returns (Success);
     rpc DeleteAll(google.protobuf.Empty) returns (Success);

readme.md

@@ -109,6 +109,14 @@ This is used to get key value pair for a particular key
 func (c Cache) Get(ctx context.Context, args *api.GetKey) (*api.Item, error)
 ```
 
+### GetByPrefix
+
+Used to get all key value pairs by prefix
+
+```go
+func (c Cache) GetByPrefix(ctx context.Context, args *api.GetKey) (*api.AllItems, error)
+```
+
 ### GetAllItems
 
 Used to get all key value pairs
@@ -135,27 +143,29 @@ func (c Cache) DeleteAll(ctx context.Context, in *empty.Empty) (*api.Success, er
 
 ## Testing
 
-After running `make build` just run `make test` to run the tests. It has **coverage of 91.2%**
+After running `make build` just run `make test` to run the tests. It has **coverage of 92.7%**
 
 ```bash
 go test api/server/* -v -cover -race
 === RUN   TestAdd
---- PASS: TestAdd (0.04s)
+--- PASS: TestAdd (0.03s)
 === RUN   TestGet
---- PASS: TestGet (0.03s)
+--- PASS: TestGet (0.01s)
+=== RUN   TestGetByPrefix
+--- PASS: TestGetByPrefix (0.01s)
 === RUN   TestGetAllItems
 --- PASS: TestGetAllItems (0.01s)
 === RUN   TestDeleteKey
---- PASS: TestDeleteKey (0.01s)
+--- PASS: TestDeleteKey (0.00s)
 === RUN   TestDeleteAll
---- PASS: TestDeleteAll (0.01s)
+--- PASS: TestDeleteAll (0.00s)
 === RUN   TestGetDeletedKey
 --- PASS: TestGetDeletedKey (0.01s)
 === RUN   TestDeleteKeyByExpiration
 --- PASS: TestDeleteKeyByExpiration (2.01s)
 PASS
-coverage: 91.2% of statements
-ok  	command-line-arguments	3.617s	coverage: 91.2% of statements
+coverage: 92.7% of statements
+ok  	command-line-arguments	3.709s	coverage: 92.7% of statements
 ```
 
 ## Example