// Run executes the program.
func (m *Main) Run(args ...string) error {
// Create logger.
m.logger = log.New(m.Stdout, "", log.LstdFlags)
// Parse command line flags.
opt, err := m.ParseFlags(args...)
if err != nil {
return err
}
// Set up advertised address and default peer set.
m.advertiseAddr = MergeHostPort(opt.Host, opt.Addr)
if len(opt.Peers) == 0 {
opt.Peers = []string{m.advertiseAddr}
}
// Create a slice of peers with their HTTP address set instead.
httpPeers, err := SetPortSlice(opt.Peers, opt.Addr)
if err != nil {
return fmt.Errorf("set port slice: %s", err)
}
m.peers = httpPeers
// Initialise the default client using the peer list
os.Setenv("DISCOVERD", strings.Join(opt.Peers, ","))
discoverd.DefaultClient = discoverd.NewClient()
// if there is a discoverd process already running on this
// address perform a deployment by starting a proxy DNS server
// and shutting down the old discoverd job
var deploy *dd.Deployment
var targetLogIndex dt.TargetLogIndex
target := fmt.Sprintf("http://%s:1111", opt.Host)
m.logger.Println("checking for existing discoverd process at", target)
if err := discoverd.NewClientWithURL(target).Ping(target); err == nil {
m.logger.Println("discoverd responding at", target, "taking over")
deploy, err = dd.NewDeployment("discoverd")
if err != nil {
return err
}
m.logger.Println("Created deployment")
if err := deploy.MarkPerforming(m.advertiseAddr, 60); err != nil {
return err
}
m.logger.Println("marked", m.advertiseAddr, "as performing in deployent")
addr, resolvers := waitHostDNSConfig()
if opt.DNSAddr != "" {
addr = opt.DNSAddr
}
if len(opt.Recursors) > 0 {
resolvers = opt.Recursors
}
m.logger.Println("starting proxy DNS server")
if err := m.openDNSServer(addr, resolvers); err != nil {
return fmt.Errorf("Failed to start DNS server: %s", err)
}
m.logger.Printf("discoverd listening for DNS on %s", addr)
targetLogIndex, err = discoverd.NewClientWithURL(target).Shutdown(target)
if err != nil {
return err
}
// Sleep for 2x the election timeout.
// This is to work around an issue with hashicorp/raft that can allow us to be elected with
// no log entries, hence truncating the log and losing all data!
time.Sleep(2 * time.Second)
} else {
m.logger.Println("failed to contact existing discoverd server, starting up without takeover")
m.logger.Println("err:", err)
}
// Open listener.
ln, err := net.Listen("tcp4", opt.Addr)
if err != nil {
return err
}
m.ln = keepalive.Listener(ln)
// Open mux
m.mux = mux.New(m.ln)
go m.mux.Serve()
m.dataDir = opt.DataDir
// if the advertise addr is not in the peer list we are proxying
proxying := true
for _, addr := range m.peers {
if addr == m.advertiseAddr {
proxying = false
break
}
}
if proxying {
// Notify user that we're proxying if the store wasn't initialized.
m.logger.Println("advertised address not in peer set, joining as proxy")
} else {
// Open store if we are not proxying.
if err := m.openStore(); err != nil {
return fmt.Errorf("Failed to open store: %s", err)
}
}
// Wait for the store to catchup before switching to local store if we are doing a deployment
if m.store != nil && targetLogIndex.LastIndex > 0 {
for m.store.LastIndex() < targetLogIndex.LastIndex {
m.logger.Println("Waiting for store to catchup, current:", m.store.LastIndex(), "target:", targetLogIndex.LastIndex)
time.Sleep(100 * time.Millisecond)
}
}
// If we already started the DNS server as part of a deployment above,
// and we have an initialized store, just switch from the proxy store
// to the initialized store.
//
// Else if we have a DNS address, start a DNS server right away.
//
// Otherwise wait for the host network to come up and then start a DNS
// server.
if m.dnsServer != nil && m.store != nil {
m.dnsServer.SetStore(m.store)
} else if opt.DNSAddr != "" {
if err := m.openDNSServer(opt.DNSAddr, opt.Recursors); err != nil {
return fmt.Errorf("Failed to start DNS server: %s", err)
}
m.logger.Printf("discoverd listening for DNS on %s", opt.DNSAddr)
} else if opt.WaitNetDNS {
go func() {
addr, resolvers := waitHostDNSConfig()
m.mu.Lock()
if err := m.openDNSServer(addr, resolvers); err != nil {
log.Fatalf("Failed to start DNS server: %s", err)
}
m.mu.Unlock()
m.logger.Printf("discoverd listening for DNS on %s", addr)
// Notify webhook.
if opt.Notify != "" {
m.Notify(opt.Notify, addr)
}
}()
}
if err := m.openHTTPServer(); err != nil {
return fmt.Errorf("Failed to start HTTP server: %s", err)
}
if deploy != nil {
if err := deploy.MarkDone(m.advertiseAddr); err != nil {
return err
}
m.logger.Println("marked", m.advertiseAddr, "as done in deployment")
}
// Notify user that the servers are listening.
m.logger.Printf("discoverd listening for HTTP on %s", opt.Addr)
// Wait for leadership.
if err := m.waitForLeader(IndefiniteTimeout); err != nil {
return err
}
// Notify URL that discoverd is running.
httpAddr := ln.Addr().String()
host, port, _ := net.SplitHostPort(httpAddr)
if host == "0.0.0.0" {
httpAddr = net.JoinHostPort(os.Getenv("EXTERNAL_IP"), port)
}
m.Notify(opt.Notify, opt.DNSAddr)
go func() {
for {
hb, err := discoverd.AddServiceAndRegister("discoverd", httpAddr)
if err != nil {
m.logger.Println("failed to register service/instance, retrying in 5 seconds:", err)
time.Sleep(5 * time.Second)
continue
}
m.mu.Lock()
m.hb = hb
m.mu.Unlock()
break
}
}()
return nil
}
// Run executes the program.
func (m *Main) Run(args ...string) error {
// Create logger.
m.logger = log.New(m.Stdout, "", log.LstdFlags)
// Parse command line flags.
opt, err := m.ParseFlags(args...)
if err != nil {
return err
}
// Set up advertised address and default peer set.
advertiseAddr := MergeHostPort(opt.Host, opt.Addr)
if len(opt.Peers) == 0 {
opt.Peers = []string{advertiseAddr}
}
// Create a slice of peers with their HTTP address set instead.
httpPeers, err := SetPortSlice(opt.Peers, opt.Addr)
if err != nil {
return fmt.Errorf("set port slice: %s", err)
}
// if there is a discoverd process already running on this
// address perform a deployment by starting a proxy DNS server
// and shutting down the old discoverd job
var deploy *dd.Deployment
var shutdownInfo dt.ShutdownInfo
target := fmt.Sprintf("http://%s:1111", opt.Host)
m.logger.Println("checking for existing discoverd process at", target)
if err := discoverd.NewClientWithHTTP(target, &http.Client{}).Ping(); err == nil {
m.logger.Println("discoverd responding at", target, "taking over")
// update DISCOVERD environment variable so that the default
// discoverd client connects to the instance we intend to replace.
os.Setenv("DISCOVERD", target)
discoverd.DefaultClient = discoverd.NewClient()
deploy, err = dd.NewDeployment("discoverd")
if err != nil {
return err
}
m.logger.Println("Created deployment")
if err := deploy.MarkPerforming(advertiseAddr, 60); err != nil {
return err
}
m.logger.Println("marked", advertiseAddr, "as performing in deployent")
addr, resolvers := waitHostDNSConfig()
if opt.DNSAddr != "" {
addr = opt.DNSAddr
}
if len(opt.Recursors) > 0 {
resolvers = opt.Recursors
}
m.logger.Println("starting proxy DNS server")
if err := m.openDNSServer(addr, resolvers, httpPeers); err != nil {
return fmt.Errorf("Failed to start DNS server: %s", err)
}
m.logger.Printf("discoverd listening for DNS on %s", addr)
shutdownInfo, err = discoverd.NewClientWithURL(target).Shutdown()
if err != nil {
return err
}
} else {
m.logger.Println("failed to contact existing discoverd server, starting up without takeover")
}
// Open listener.
ln, err := net.Listen("tcp4", opt.Addr)
if err != nil {
return err
}
m.ln = ln
// Multiplex listener to store and http api.
storeLn, httpLn := server.Mux(ln)
// Open store if we are not proxying.
if err := m.openStore(opt.DataDir, storeLn, advertiseAddr, opt.Peers); err != nil {
return fmt.Errorf("Failed to open store: %s", err)
}
// Notify user that we're proxying if the store wasn't initialized.
if m.store == nil {
fmt.Fprintln(m.Stderr, "advertised address not in peer set, joining as proxy")
}
// Wait for the store to catchup before switching to local store if we are doing a deployment
if m.store != nil && shutdownInfo.LastIndex > 0 {
for m.store.LastIndex() < shutdownInfo.LastIndex {
m.logger.Println("Waiting for store to catchup, current:", m.store.LastIndex(), "target:", shutdownInfo.LastIndex)
time.Sleep(100 * time.Millisecond)
}
}
// If we already started the DNS server as part of a deployment above,
// and we have an initialized store, just switch from the proxy store
// to the initialized store.
//
// Else if we have a DNS address, start a DNS server right away.
//
// Otherwise wait for the host network to come up and then start a DNS
// server.
if m.dnsServer != nil && m.store != nil {
m.dnsServer.SetStore(m.store)
} else if opt.DNSAddr != "" {
if err := m.openDNSServer(opt.DNSAddr, opt.Recursors, httpPeers); err != nil {
return fmt.Errorf("Failed to start DNS server: %s", err)
}
m.logger.Printf("discoverd listening for DNS on %s", opt.DNSAddr)
} else if opt.WaitNetDNS {
go func() {
addr, resolvers := waitHostDNSConfig()
if err := m.openDNSServer(addr, resolvers, httpPeers); err != nil {
log.Fatalf("Failed to start DNS server: %s", err)
}
m.logger.Printf("discoverd listening for DNS on %s", addr)
// Notify webhook.
if opt.Notify != "" {
m.Notify(opt.Notify, "", addr)
}
}()
}
if err := m.openHTTPServer(httpLn, opt.Peers); err != nil {
return fmt.Errorf("Failed to start HTTP server: %s", err)
}
if deploy != nil {
if err := deploy.MarkDone(advertiseAddr); err != nil {
return err
}
m.logger.Println("marked", advertiseAddr, "as done in deployment")
}
// Notify user that the servers are listening.
m.logger.Printf("discoverd listening for HTTP on %s", opt.Addr)
// FIXME(benbjohnson): Join to cluster.
// Wait for leadership.
if err := m.waitForLeader(LeaderTimeout); err != nil {
return err
}
// Notify URL that discoverd is running.
httpAddr := ln.Addr().String()
host, port, _ := net.SplitHostPort(httpAddr)
if host == "0.0.0.0" {
httpAddr = net.JoinHostPort(os.Getenv("EXTERNAL_IP"), port)
}
m.Notify(opt.Notify, "http://"+httpAddr, opt.DNSAddr)
go discoverd.NewClientWithURL("http://"+httpAddr).AddServiceAndRegister("discoverd", httpAddr)
return nil
}
