Add usage documentation

README.md

@@ -6,9 +6,22 @@
 
 A Web GUI written in Go to manage S3 buckets from any provider.
 
+![Screenshot](https://raw.githubusercontent.com/mastertinner/s3manager/master/screenshot.png)
+
+## Usage
+
+The application can be configured with the following environment variables:
+
+- `ENDPOINT`: The endpoint of your S3 server (defaults to `s3.amazonaws.com`)
+- `ACCESS_KEY_ID`: Your S3 access key ID (required)
+- `SECRET_ACCESS_KEY`: Your S3 secret access key (required)
+- `PORT`: The port the app should listen on (defaults to `8080`)
+
+Then simply run the binary.
+
 ## Build and Run Locally
 
-1.  Run `make`
+1.  Run `make build`
 1.  Execute the created binary and visit <http://localhost:8080>
 
 ## Run Tests
@@ -21,7 +34,7 @@ The image is available on [Docker Hub](https://hub.docker.com/r/mastertinner/s3m
 
 1.  Run `make build-docker`
 
-## Run on Cloud Foundry
+## Deploy to Cloud Foundry
 
 1.  Modify `deployments/cf/*` to your liking
 1.  Run `make deploy-cf`

cmd/s3manager/main.go

@@ -14,26 +14,23 @@ import (
 )
 
 func main() {
+	endpoint, ok := os.LookupEnv("ENDPOINT")
+	if !ok {
+		endpoint = "s3.amazonaws.com"
+	}
 	accessKeyID, ok := os.LookupEnv("ACCESS_KEY_ID")
 	if !ok {
 		log.Fatal("please provide ACCESS_KEY_ID")
 	}
-
 	secretAccessKey, ok := os.LookupEnv("SECRET_ACCESS_KEY")
 	if !ok {
 		log.Fatal("please provide SECRET_ACCESS_KEY")
 	}
-
 	port, ok := os.LookupEnv("PORT")
 	if !ok {
 		port = "8080"
 	}
 
-	endpoint, ok := os.LookupEnv("ENDPOINT")
-	if !ok {
-		endpoint = "s3.amazonaws.com"
-	}
-
 	tmplDir := filepath.Join("web", "template")
 
 	// Set up S3 client