Using cli.Context in server, updating readme

cmd/grpc-lookaside.go

@@ -17,7 +17,7 @@ func main() {
 	app := cli.NewApp()
 	app.Name = "grpc-lookaside"
 	app.Usage = "A lookaside load balancer for gRPC service requests."
-	app.Version = "0.0.4"
+	app.Version = "0.0.6"
 	app.Flags = []cli.Flag{
 		cli.StringFlag{
 			Name:  "bind,b",
@@ -50,13 +50,12 @@ func main() {
 		if err != nil {
 			log.Fatalf("Failed to listen: %v", err)
 		}
-
 		log.Printf("Listening for requests at %s\n", c.String("bind"))
 		defer listener.Close()
 
 		// register the server implementation with the generated handlers and listen for incoming requests
 		server := grpc.NewServer()
-		pb.RegisterLookasideServer(server, lookaside.NewServer(c.String("consul"), c.String("datacenter"), c.Float64("refresh")))
+		pb.RegisterLookasideServer(server, lookaside.NewServer(c))
 		return server.Serve(listener)
 
 	}

readme.md

@@ -7,17 +7,20 @@ Unsurprisingly, this service uses a gRPC-based interface to request addresses (s
 services and messages). 
 
 ## CLI
-The application has a simple CLI interface and supports the following arguments:
+The application has a simple CLI interface and supports the following arguments and environment variable configurations:
 
 ### --bind, b
 The address that the service will bind to in {host}:{port} format. Defaults to `:3000`.
 
-### --consul, c
+### --consul, c [$CONSUL_ADDRESS]
 The address of the Consul agent used for service discovery. Defaults to `127.0.0.1:8500` (local agent).
 
-### --datacenter, d
+### --datacenter, d [$CONSUL_DATACENTER]
 The Consul datacenter to query for services. Defaults to `dc1`.
 
+### --refresh, r [$REFRESH]
+Time, in seconds, between service address list refreshes. Defaults to 10 seconds.
+
 ## Building
 You'll need a working install of the Go programming language to compile the go code and the GNU `make` tool for running
 the builds. Once everything is installed and setup, just run:

server.go

@@ -6,16 +6,16 @@ import (
 	"time"
 
 	"github.com/hashicorp/consul/api"
+	"github.com/urfave/cli"
 	"golang.org/x/net/context"
 
 	pb "github.com/markitondemand/grpc-lookaside/_proto"
 )
 
 type Server struct {
-	ConsulAddress    string
-	ConsulDatacenter string
-	routers          map[string]*Router
-	refreshInterval  float64
+	context         *cli.Context
+	routers         map[string]*Router
+	refreshInterval float64
 }
 
 func (s *Server) Resolve(ctx context.Context, input *pb.Request) (*pb.Response, error) {
@@ -32,7 +32,7 @@ func (s *Server) Resolve(ctx context.Context, input *pb.Request) (*pb.Response,
 			return nil, err
 		}
 
-		s.routers[input.Service] = &Router{Addresses: addresses, LastRefresh: time.Now(), RefreshInterval: s.refreshInterval}
+		s.routers[input.Service] = &Router{Addresses: addresses, LastRefresh: time.Now(), RefreshInterval: s.context.Float64("refresh")}
 	}
 
 	// determine the type of routing requested, and resolve an address
@@ -58,7 +58,7 @@ func (s *Server) refreshAddresses(service string) ([]string, error) {
 	addressSet := make(map[string]struct{})
 
 	// create a consul client
-	consul, err := api.NewClient(&api.Config{Address: s.ConsulAddress, Datacenter: s.ConsulDatacenter})
+	consul, err := api.NewClient(&api.Config{Address: s.context.String("address"), Datacenter: s.context.String("datacenter")})
 	if err != nil {
 		return make([]string, 0), err
 	}
@@ -84,11 +84,9 @@ func (s *Server) refreshAddresses(service string) ([]string, error) {
 
 }
 
-func NewServer(address, datacenter string, refresh float64) *Server {
+func NewServer(c *cli.Context) *Server {
 	return &Server{
-		ConsulAddress:    address,
-		ConsulDatacenter: datacenter,
-		routers:          map[string]*Router{},
-		refreshInterval:  refresh,
+		context: c,
+		routers: map[string]*Router{},
 	}
 }