add cmd flags, listen to signals, and use kit/log for logging
Marcel Hauf
8 years ago
| 2 | 2 | import ( |
| 3 | 3 | "bytes" |
| 4 | 4 | "encoding/json" |
| 5 | "flag" | |
| 6 | "fmt" | |
| 5 | 7 | "io" |
| 6 | 8 | "io/ioutil" |
| 7 | "log" | |
| 9 | stdlog "log" | |
| 8 | 10 | "net/http" |
| 9 | 11 | "net/url" |
| 12 | "os" | |
| 13 | "os/signal" | |
| 10 | 14 | "strings" |
| 15 | "syscall" | |
| 11 | 16 | |
| 12 | 17 | "golang.org/x/net/context" |
| 13 | 18 | |
| 16 | 21 | "github.com/go-kit/kit/endpoint" |
| 17 | 22 | "github.com/go-kit/kit/loadbalancer" |
| 18 | 23 | "github.com/go-kit/kit/loadbalancer/consul" |
| 19 | klog "github.com/go-kit/kit/log" | |
| 24 | log "github.com/go-kit/kit/log" | |
| 20 | 25 | httptransport "github.com/go-kit/kit/transport/http" |
| 21 | 26 | |
| 22 | 27 | "github.com/hashicorp/consul/api" |
| 25 | 30 | var ( |
| 26 | 31 | discoveryClient consul.Client |
| 27 | 32 | ctx = context.Background() |
| 33 | logger log.Logger | |
| 28 | 34 | ) |
| 29 | 35 | |
| 30 | 36 | func main() { |
| 37 | fs := flag.NewFlagSet("", flag.ExitOnError) | |
| 38 | var ( | |
| 39 | httpAddr = fs.String("http.addr", ":8000", "Address for HTTP (JSON) server") | |
| 40 | consulAddr = fs.String("consul.addr", "", "Consul agent address") | |
| 41 | ) | |
| 42 | flag.Usage = fs.Usage | |
| 43 | if err := fs.Parse(os.Args[1:]); err != nil { | |
| 44 | fmt.Fprintf(os.Stderr, "%v", err) | |
| 45 | os.Exit(1) | |
| 46 | } | |
| 31 | 47 | |
| 48 | // log | |
| 49 | logger = log.NewLogfmtLogger(os.Stderr) | |
| 50 | logger = log.NewContext(logger).With("ts", log.DefaultTimestampUTC).With("caller", log.DefaultCaller) | |
| 51 | stdlog.SetFlags(0) // flags are handled by Go kit's logger | |
| 52 | stdlog.SetOutput(log.NewStdlibAdapter(logger)) // redirect anything using stdlib log to us | |
| 53 | ||
| 54 | // errors | |
| 55 | errc := make(chan error) | |
| 56 | go func() { | |
| 57 | errc <- interrupt() | |
| 58 | }() | |
| 59 | ||
| 60 | // consul | |
| 32 | 61 | consulConfig := api.DefaultConfig() |
| 62 | if len(*consulAddr) > 0 { | |
| 63 | consulConfig.Address = *consulAddr | |
| 64 | } | |
| 33 | 65 | consulClient, err := api.NewClient(consulConfig) |
| 34 | 66 | if err != nil { |
| 35 | log.Fatal(err) | |
| 67 | logger.Log("fatal", err) | |
| 36 | 68 | } |
| 37 | 69 | discoveryClient = consul.NewClient(consulClient) |
| 38 | 70 | |
| 39 | r := mux.NewRouter() | |
| 40 | r.HandleFunc("/api/{service}/{method}", apiGateway) | |
| 71 | // apigateway | |
| 72 | go func() { | |
| 73 | r := mux.NewRouter() | |
| 74 | r.HandleFunc("/api/{service}/{method}", apiGateway) | |
| 75 | errc <- http.ListenAndServe(*httpAddr, r) | |
| 76 | }() | |
| 41 | 77 | |
| 42 | http.ListenAndServe(":8000", r) | |
| 78 | // wait for interrupt/error | |
| 79 | logger.Log("fatal", <-errc) | |
| 80 | } | |
| 81 | ||
| 82 | func interrupt() error { | |
| 83 | c := make(chan os.Signal) | |
| 84 | signal.Notify(c, syscall.SIGINT, syscall.SIGTERM) | |
| 85 | return fmt.Errorf("%s", <-c) | |
| 43 | 86 | } |
| 44 | 87 | |
| 45 | 88 | func apiGateway(w http.ResponseWriter, r *http.Request) { |
| 48 | 91 | method := vars["method"] |
| 49 | 92 | e, err := getEndpoint(service, method) |
| 50 | 93 | if err != nil { |
| 51 | log.Print(err) | |
| 94 | logger.Log("error", err) | |
| 52 | 95 | return |
| 53 | 96 | } |
| 54 | 97 | |
| 56 | 99 | dec := json.NewDecoder(r.Body) |
| 57 | 100 | err = dec.Decode(&val) |
| 58 | 101 | if err != nil { |
| 59 | log.Print(err) | |
| 102 | logger.Log("warning", err) | |
| 103 | fmt.Fprint(w, err) | |
| 60 | 104 | return |
| 61 | 105 | } |
| 62 | 106 | |
| 63 | 107 | resp, err := e(ctx, val) |
| 64 | 108 | if err != nil { |
| 65 | log.Print(err) | |
| 109 | logger.Log("warning", err) | |
| 110 | fmt.Fprint(w, err) | |
| 66 | 111 | return |
| 67 | 112 | } |
| 68 | 113 | enc := json.NewEncoder(w) |
| 69 | 114 | err = enc.Encode(resp) |
| 70 | 115 | if err != nil { |
| 71 | log.Print(err) | |
| 116 | logger.Log("warning", err) | |
| 117 | fmt.Fprint(w, err) | |
| 72 | 118 | return |
| 73 | 119 | } |
| 74 | 120 | } |
| 84 | 130 | } |
| 85 | 131 | } |
| 86 | 132 | |
| 87 | publisher, err := consul.NewPublisher(discoveryClient, factory(ctx, method), klog.NewLogfmtLogger(&klog.StdlibWriter{}), se) | |
| 133 | publisher, err := consul.NewPublisher(discoveryClient, factory(ctx, method), log.NewLogfmtLogger(&log.StdlibWriter{}), se) | |
| 134 | publisher.Endpoints() | |
| 88 | 135 | if err != nil { |
| 89 | 136 | return nil, err |
| 90 | 137 | } |
| 128 | 175 | } |
| 129 | 176 | |
| 130 | 177 | func encodeRequest(r *http.Request, request interface{}) error { |
| 131 | log.Printf("encode req: %v", request) | |
| 132 | 178 | var buf bytes.Buffer |
| 133 | 179 | if err := json.NewEncoder(&buf).Encode(request); err != nil { |
| 134 | log.Print(err) | |
| 135 | 180 | return err |
| 136 | 181 | } |
| 137 | 182 | r.Body = ioutil.NopCloser(&buf) |