docs: added README and travis.yml

.travis.yml

@@ -0,0 +1,18 @@
+language: go
+matrix:
+  include:
+    - go: 1.x
+      env: LATEST=true
+    - go: 1.11.x
+    - go: 1.12.x
+    - go: 1.13.x
+    - go: tip
+  allow_failures:
+    - go: tip
+
+install:
+  - export GO111MODULE=on
+  - go get -t -v ./...
+
+script:
+  - go test -v ./...

README.md

@@ -1,43 +1,233 @@
-Gache
-=====
+[![TravisBuildStatus](https://api.travis-ci.org/eko/gache.svg?branch=master)](https://travis-ci.org/eko/gache)
+[![GoDoc](https://godoc.org/github.com/eko/gache?status.png)](https://godoc.org/github.com/eko/gache)
+[![GoReportCard](https://goreportcard.com/badge/github.com/eko/gache)](https://goreportcard.com/report/github.com/eko/gache)
 
+Go + Cache = Gache
+==================
+
+An extendable Go cache library that brings you a lot of features for caching data.
+
+## Overview
+
+Here is what it brings in detail:
+
+* ✅ Multiple cache stores: actually in memory, redis, or your own custom store
+* ✅ A chain cache: use multiple cache with a priority order (memory then fallback to a redis shared cache for instance)
+* ✅ A loadable cache: allow you to call a callback function to put your data back in cache
+* ✅ A metric cache to let you store metrics about your caches usage (hits, miss, set success, set error, ...)
+* ✅ A marshaler to automatically marshal/unmarshal your cache values as a struct
+
+## Built-in stores
+
+* [Ristretto](https://github.com/dgraph-io/ristretto) (in memory)
+* [Go-Redis](github.com/go-redis/redis/v7) (redis)
+* More to come soon
+
+## Built-in metrics providers
+
+* [Prometheus](https://github.com/prometheus/client_golang)
+
+## Available cache features in detail
+
+### A simple cache
+
+Here is a simple cache instanciation with Redis but you can also look at other available stores:
 
 ```go
-// Initialize stores
+redisStore := store.NewRedis(redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"}))
+
+cache.New(redisStore, 15*time.Second)
+err := cache.Set("my-key", "my-value)
+if err != nil {
+    panic(err)
+}
+
+value := cache.Get("my-key")
+```
+
+### A chained cache
+
+Here, we will chain caches in the following order: first in memory with Ristretto store, then in Redis (as a fallback):
+
+```go
+// Initialize Ristretto cache and Redis client
 ristrettoCache, err := ristretto.NewCache(&ristretto.Config{NumCounters: 1000, MaxCost: 100, BufferItems: 64})
 if err != nil {
     panic(err)
 }
 
-ristrettoStore := store.NewRistrettoStore(ristrettoCache)
-redisStore := store.NewRedisStore(redis.NewClient(&redis.Options{Addr: host}))
+redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
+
+// Initialize stores
+ristrettoStore := store.NewRistretto(ristrettoCache)
+redisStore := store.NewRedis(redisClient)
+
+// Initialize chained cache
+cache := cache.NewChain(
+    cache.New(ristrettoStore, 5*time.Second),
+    cache.New(redisStore, 15*time.Second),
+)
+
+// ... Then, do what you want with your cache
+```
+
+`Chain` cache also put data back in previous caches when it's found so in this case, if ristretto doesn't have the data in its cache but redis have, data will also get setted back into ristretto (memory) cache.
+
+### A loadable cache
 
-// Initialize Prometheus metrics collector
-promMetrics := metrics.NewPrometheusMetrics("my-test-app")
+This cache will provide a load function that acts as a callable function and will set your data back in your cache in case they are not available:
+
+```go
+// Initialize Redis client and store
+redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
+redisStore := store.NewRedis(redisClient)
 
 // Initialize a load function that loads your data from a custom source
 loadFunction := func(key interface{}) (interface{}, error) {
     // ... retrieve value from available source
-    return &Book{ID: 1, Title: "My test amazing book", Slug: "my-test-amazing-book"}, nil
+    return &Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}, nil
 }
 
-// Initialize a chained cache (memory with Ristretto then Redis) with Prometheus metrics
-// and a load function that will put data back into caches if none has the value
-cache := cache.NewMetricCache(promMetrics, cache.NewLoadableCache(
-    loadFunction,
-    cache.NewChainCache(
-        cache.NewCache(ristrettoStore, 5 * time.Second),
-        cache.NewCache(redisStore, 15 * time.Second),
-    ),
-))
+// Initialize loadable cache
+cache := cache.NewLoadable(loadFunction, cache.New(redisStore, 15*time.Second))
+
+// ... Then, you can get your data and your function will automatically put them in cache(s)
+```
+
+### A metric cache to retrieve cache statistics
+
+This cache will record metrics depending on the metric provider you pass to it. Here we give a Prometheus provider:
+
+```go
+// Initialize Redis client and store
+redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
+redisStore := store.NewRedis(redisClient)
+
+// Initializes Prometheus metrics service
+promMetrics := metrics.NewPrometheus("my-test-app")
+
+// Initialize metric cache
+cache := cache.NewMetric(promMetrics, cache.New(redisStore, 15*time.Second))
+
+// ... Then, you can get your data and metrics will be observed by Prometheus
+```
 
-key := Book{Slyg: "my-test-amazing-book"}
-value := Book{ID: 1, Title: "My test amazing book", Slug: "my-test-amazing-book"}
+Of course, you can pass a `Chain` cache into the `Loadable` one so if your data is not available in all caches, it will bring it back in all caches.
 
-cache.Set(key, value)
-returnedValue := cache.Get(key) // Returns a type interface{}, cast it back to Book struct
+### A marshaler wraper
 
-if cachedValue, ok := returnedValue.(*Book); ok {
-    fmt.Printf("%v", cachedValue)
+Some caches like Redis stores and returns the value as a string so you have to marshal/unmarshal your structs if you want to cache an object. That's why we bring a marshaler service that wraps your cache and make the work for you:
+
+```go
+// Initialize Redis client and store
+redisClient := redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"})
+redisStore := store.NewRedis(redisClient)
+
+// Initialize chained cache
+cache := cache.NewMetric(promMetrics, cache.New(redisStore, 15*time.Second))
+
+// Initializes marshaler
+marshaller := marshaler.New(cache)
+
+key := BookQuery{Slug: "my-test-amazing-book"}
+value := Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}
+
+err = marshaller.Set(key, value)
+if err != nil {
+    panic(err)
+}
+
+returnedValue, err := marshaller.Get(key, new(Book))
+if err != nil {
+    panic(err)
+}
+
+// Then, do what you want with the  value
+```
+
+The only thing you have to do is to specify the struct in which you want your value to be unmarshalled as a second argument when calling the `.Get()` method.
+
+### All together!
+
+Finally, you can mix all of these available caches or bring them together to build the cache you want to.
+Here is a full example of how it can looks like:
+
+```go
+package main
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/dgraph-io/ristretto"
+	"github.com/eko/gache/cache"
+	"github.com/eko/gache/marshaler"
+	"github.com/eko/gache/metrics"
+	"github.com/eko/gache/store"
+	"github.com/go-redis/redis/v7"
+)
+
+// Book is a test struct that represents a single book
+type Book struct {
+	ID   int
+	Name string
+	Slug string
+}
+
+func main() {
+	// Initialize Prometheus metrics collector
+	promMetrics := metrics.NewPrometheus("my-test-app")
+
+	ristrettoCache, err := ristretto.NewCache(&ristretto.Config{NumCounters: 1000, MaxCost: 100, BufferItems: 64})
+	if err != nil {
+		panic(err)
+	}
+
+	ristrettoStore := store.NewRistretto(ristrettoCache)
+	redisStore := store.NewRedis(redis.NewClient(&redis.Options{Addr: "127.0.0.1:6379"}))
+
+	// Initialize a load function that loads your data from a custom source
+	loadFunction := func(key interface{}) (interface{}, error) {
+		// ... retrieve value from available source
+		return &Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}, nil
+	}
+
+	// Initialize a chained cache (memory with Ristretto then Redis) with Prometheus metrics
+	// and a load function that will put data back into caches if none has the value
+	cache := cache.NewMetric(promMetrics, cache.NewLoadable(loadFunction,
+		cache.NewChain(
+			cache.New(ristrettoStore, 5*time.Second),
+			cache.New(redisStore, 15*time.Second),
+		),
+	))
+
+	marshaller := marshaler.New(cache)
+
+	key := Book{Slug: "my-test-amazing-book"}
+	value := Book{ID: 1, Name: "My test amazing book", Slug: "my-test-amazing-book"}
+
+	err = marshaller.Set(key, value)
+	if err != nil {
+		panic(err)
+	}
+
+	returnedValue, err := marshaller.Get(key, new(Book))
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("%v\n", returnedValue)
 }
 ```
+
+## Community
+
+Please feel free to contribute on this library and do not hesitate to open an issue if you want to discuss about a feature.
+
+## Run tests
+
+Test suite can be run with:
+
+```bash
+$ go test -v ./...
+```