Added a Readme

Author: muki119

README.md

@@ -1 +1,138 @@
-# go-slim-event-bus
+# go-slim-event-bus
+
+A strongly opinionated Redis streams abstraction mainly designed for simple inter-service communication. The purpose of this module is for it to run alongside a service's HTTP server within the same binary.
+
+## Features 
+- Concurrent Message Processing.
+- Pending message housekeeping.
+    - In the instance listen, the program will process a certain number of pending messages before taking new incoming messages.
+- Graceful Shutdown.
+- Timeout managed handlers to prevent processes from running indefinitely .
+
+# Installation 
+In terminal , with your Go project as the current directory paste the following :
+``` bash
+go get github.com/muki119/go-slim-event-bus
+```
+
+# Usage
+## Create Event Bus instance from config.
+``` Go
+ebConfig := &seb.EventBusConfig{
+    Connection:    conn,
+    ConsumerName:  "ConsumerFizz",
+    ConsumerGroup: "FizzGroup",
+    MaxCount:      100,
+    Timeout:       3 * time.Second,
+    MaxConcurrent: int64(runtime.NumCPU() / 10),
+}
+eventBus := ebConfig.NewFromConfig()
+```
+
+## Create Event Bus instance from the constructor.
+```Go
+eventBus := seb.NewStreamsEventBus("ConsumerFizz", "FizzGroup", conn, 100, 3*time.Second, int64(runtime.NumCPU()/10))
+```
+
+## Register a Stream to listen to and a handler for its incoming data.
+Registration of a stream and handler function should be made before.
+```Go 
+eventBus.StreamHandler("user.created", HandleUserCreation)
+```
+
+## To Listen 
+The listen method returns a channel that will only return errors and no other value.   
+This is to ensure the program is non-blocking
+``` Go
+err := <-eventBus.Listen() 
+```
+
+## To close the instance. 
+Waits for all messages acquired before closure to be processed or timeout, then closes the listener and connection.
+``` Go
+err := eventBus.Close() 
+```
+
+
+## Configuration options
+|Field|Description|
+|-|-|
+|Connection|Pointer to the Redis connection instance.|
+|ConsumerName|Name of the consumer instance. Used by the client to identify itself within the consumer groups.|
+|ConsumerGroup|Name of consumer group to be attached to for each stream.|
+|MaxCount|Maximum number of messages in each stream every read.|
+|Timeout|Max amount of time for handlers to process a message.|
+|MaxConcurrent|Maximum amount of messages that can be concurrently handled.|
+
+## Examples
+### From Config
+``` Go
+ebConfig := &seb.EventBusConfig{
+    Connection:    conn,
+    ConsumerName:  "ConsumerFizz",
+    ConsumerGroup: "FizzGroup",
+    MaxCount:      100,
+    Timeout:       3 * time.Second,
+    MaxConcurrent: int64(runtime.NumCPU() / 10),
+}
+eventBus := ebConfig.NewFromConfig()
+
+shutdownChan := make(chan struct{}, 1)
+go func() {
+    exitSignal := make(chan os.Signal)
+    signal.Notify(exitSignal, syscall.SIGINT, syscall.SIGTERM)
+    <-exitSignal
+    if err := eventBus.Close(); err != nil {
+        fmt.Printf("Error occurred while closing event bus: %v", err)
+    }
+    close(shutdownChan)
+}()
+
+eventBus.StreamHandler("user.created", HandleUserCreation)
+eventBus.StreamHandler("user.deleted", HandleUserDeletion)
+
+if err := <-eventBus.Listen(); err != nil {
+    fmt.Printf("Error occurred: %v", err)
+    if err := eventBus.Close(); err != nil {
+        fmt.Printf("Error occurred while closing event bus: %v", err)
+    }
+    close(shutdownChan)
+}
+<-shutdownChan
+```
+
+### From Constructor
+```Go
+eventBus := seb.NewStreamsEventBus("ConsumerFizz", "FizzGroup", conn, 100, 3*time.Second, int64(runtime.NumCPU()/10))
+
+shutdownChan := make(chan struct{}, 1)
+go func() {
+    exitSignal := make(chan os.Signal)
+    signal.Notify(exitSignal, syscall.SIGINT, syscall.SIGTERM)
+    <-exitSignal
+    if err := eventBus.Close(); err != nil {
+        fmt.Printf("Error occurred while closing event bus: %v", err)
+    }
+    close(shutdownChan)
+}()
+
+eventBus.StreamHandler("user.created", HandleUserCreation)
+eventBus.StreamHandler("user.deleted", HandleUserDeletion)
+
+if err := <-eventBus.Listen(); err != nil {
+    fmt.Printf("Error occurred: %v", err)
+    if err := eventBus.Close(); err != nil {
+        fmt.Printf("Error occurred while closing event bus: %v", err)
+    }
+    close(shutdownChan)
+}
+<-shutdownChan
+```
+
+## Recommendations 
+- For handler functions , keep them aware of timeout context passed in each handler.
+
+
+## Future Additions/Improvments
+ - Dead letter queueing 
+