open-consul/command/agent/command.go

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package agent
import (
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"flag"
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"fmt"
"github.com/armon/go-metrics"
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"github.com/hashicorp/logutils"
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"github.com/mitchellh/cli"
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"io"
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"net"
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"os"
"os/signal"
"runtime"
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"strings"
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"syscall"
"time"
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)
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// gracefulTimeout controls how long we wait before forcefully terminating
var gracefulTimeout = 5 * time.Second
// Command is a Command implementation that runs a Consul agent.
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// The command will not end unless a shutdown message is sent on the
// ShutdownCh. If two messages are sent on the ShutdownCh it will forcibly
// exit.
type Command struct {
Ui cli.Ui
ShutdownCh <-chan struct{}
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args []string
logFilter *logutils.LevelFilter
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agent *Agent
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rpcServer *AgentRPC
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httpServer *HTTPServer
dnsServer *DNSServer
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}
// readConfig is responsible for setup of our configuration using
// the command line and any file configs
func (c *Command) readConfig() *Config {
var cmdConfig Config
var configFiles []string
cmdFlags := flag.NewFlagSet("agent", flag.ContinueOnError)
cmdFlags.Usage = func() { c.Ui.Output(c.Help()) }
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cmdFlags.Var((*AppendSliceValue)(&configFiles), "config-file", "json file to read config from")
cmdFlags.Var((*AppendSliceValue)(&configFiles), "config-dir", "directory of json files to read")
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cmdFlags.StringVar(&cmdConfig.LogLevel, "log-level", "", "log level")
cmdFlags.StringVar(&cmdConfig.NodeName, "node", "", "node name")
cmdFlags.StringVar(&cmdConfig.Datacenter, "dc", "", "node datacenter")
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cmdFlags.StringVar(&cmdConfig.DataDir, "data-dir", "", "path to the data directory")
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cmdFlags.StringVar(&cmdConfig.UiDir, "ui-dir", "", "path to the web UI directory")
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cmdFlags.BoolVar(&cmdConfig.Server, "server", false, "run agent as server")
cmdFlags.BoolVar(&cmdConfig.Bootstrap, "bootstrap", false, "enable server bootstrap mode")
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cmdFlags.StringVar(&cmdConfig.ClientAddr, "client", "", "address to bind client listeners to (DNS, HTTP, RPC)")
cmdFlags.StringVar(&cmdConfig.BindAddr, "bind", "", "address to bind server listeners to")
cmdFlags.IntVar(&cmdConfig.Protocol, "protocol", -1, "protocol version")
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cmdFlags.Var((*AppendSliceValue)(&cmdConfig.StartJoin), "join",
"address of agent to join on startup")
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if err := cmdFlags.Parse(c.args); err != nil {
return nil
}
config := DefaultConfig()
if len(configFiles) > 0 {
fileConfig, err := ReadConfigPaths(configFiles)
if err != nil {
c.Ui.Error(err.Error())
return nil
}
config = MergeConfig(config, fileConfig)
}
config = MergeConfig(config, &cmdConfig)
if config.NodeName == "" {
hostname, err := os.Hostname()
if err != nil {
c.Ui.Error(fmt.Sprintf("Error determining hostname: %s", err))
return nil
}
config.NodeName = hostname
}
if config.EncryptKey != "" {
if _, err := config.EncryptBytes(); err != nil {
c.Ui.Error(fmt.Sprintf("Invalid encryption key: %s", err))
return nil
}
}
// Ensure we have a data directory
if config.DataDir == "" {
c.Ui.Error("Must specify data directory using -data-dir")
return nil
}
// Only allow bootstrap mode when acting as a server
if config.Bootstrap && !config.Server {
c.Ui.Error("Bootstrap mode cannot be enabled when server mode is not enabled")
return nil
}
// Warn if we are in bootstrap mode
if config.Bootstrap {
c.Ui.Error("WARNING: Bootstrap mode enabled! Do not enable unless necessary")
}
// Warn if using windows as a server
if config.Server && runtime.GOOS == "windows" {
c.Ui.Error("WARNING: Windows is not recommended as a Consul server. Do not use in production.")
}
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return config
}
// setupLoggers is used to setup the logGate, logWriter, and our logOutput
func (c *Command) setupLoggers(config *Config) (*GatedWriter, *logWriter, io.Writer) {
// Setup logging. First create the gated log writer, which will
// store logs until we're ready to show them. Then create the level
// filter, filtering logs of the specified level.
logGate := &GatedWriter{
Writer: &cli.UiWriter{Ui: c.Ui},
}
c.logFilter = LevelFilter()
c.logFilter.MinLevel = logutils.LogLevel(strings.ToUpper(config.LogLevel))
c.logFilter.Writer = logGate
if !ValidateLevelFilter(c.logFilter.MinLevel, c.logFilter) {
c.Ui.Error(fmt.Sprintf(
"Invalid log level: %s. Valid log levels are: %v",
c.logFilter.MinLevel, c.logFilter.Levels))
return nil, nil, nil
}
// Create a log writer, and wrap a logOutput around it
logWriter := NewLogWriter(512)
logOutput := io.MultiWriter(c.logFilter, logWriter)
return logGate, logWriter, logOutput
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}
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// setupAgent is used to start the agent and various interfaces
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func (c *Command) setupAgent(config *Config, logOutput io.Writer, logWriter *logWriter) error {
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c.Ui.Output("Starting Consul agent...")
agent, err := Create(config, logOutput)
if err != nil {
c.Ui.Error(fmt.Sprintf("Error starting agent: %s", err))
return err
}
c.agent = agent
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// Setup the RPC listener
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rpcAddr, err := config.ClientListener(config.Ports.RPC)
if err != nil {
c.Ui.Error(fmt.Sprintf("Invalid RPC bind address: %s", err))
return err
}
rpcListener, err := net.Listen("tcp", rpcAddr.String())
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if err != nil {
agent.Shutdown()
c.Ui.Error(fmt.Sprintf("Error starting RPC listener: %s", err))
return err
}
// Start the IPC layer
c.Ui.Output("Starting Consul agent RPC...")
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c.rpcServer = NewAgentRPC(agent, rpcListener, logOutput, logWriter)
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if config.Ports.HTTP > 0 {
httpAddr, err := config.ClientListener(config.Ports.HTTP)
if err != nil {
c.Ui.Error(fmt.Sprintf("Invalid HTTP bind address: %s", err))
return err
}
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server, err := NewHTTPServer(agent, config.UiDir, config.EnableDebug, logOutput, httpAddr.String())
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if err != nil {
agent.Shutdown()
c.Ui.Error(fmt.Sprintf("Error starting http server: %s", err))
return err
}
c.httpServer = server
}
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if config.Ports.DNS > 0 {
dnsAddr, err := config.ClientListener(config.Ports.DNS)
if err != nil {
c.Ui.Error(fmt.Sprintf("Invalid DNS bind address: %s", err))
return err
}
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server, err := NewDNSServer(agent, logOutput, config.Domain,
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dnsAddr.String(), config.DNSRecursor)
if err != nil {
agent.Shutdown()
c.Ui.Error(fmt.Sprintf("Error starting dns server: %s", err))
return err
}
c.dnsServer = server
}
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return nil
}
// startupJoin is invoked to handle any joins specified to take place at start time
func (c *Command) startupJoin(config *Config) error {
if len(config.StartJoin) == 0 {
return nil
}
c.Ui.Output("Joining cluster...")
n, err := c.agent.JoinLAN(config.StartJoin)
if err != nil {
return err
}
c.Ui.Info(fmt.Sprintf("Join completed. Synced with %d initial agents", n))
return nil
}
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func (c *Command) Run(args []string) int {
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c.Ui = &cli.PrefixedUi{
OutputPrefix: "==> ",
InfoPrefix: " ",
ErrorPrefix: "==> ",
Ui: c.Ui,
}
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// Parse our configs
c.args = args
config := c.readConfig()
if config == nil {
return 1
}
c.args = args
// Check GOMAXPROCS
if runtime.GOMAXPROCS(0) == 1 {
c.Ui.Error("WARNING: It is highly recommended to set GOMAXPROCS higher than 1")
}
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// Setup the log outputs
logGate, logWriter, logOutput := c.setupLoggers(config)
if logWriter == nil {
return 1
}
/* Setup telemetry
Aggregate on 10 second intervals for 1 minute. Expose the
metrics over stderr when there is a SIGUSR1 received.
*/
inm := metrics.NewInmemSink(10*time.Second, time.Minute)
metrics.DefaultInmemSignal(inm)
metricsConf := metrics.DefaultConfig("consul")
// Optionally configure a statsite sink if provided
if config.StatsiteAddr != "" {
sink, err := metrics.NewStatsiteSink(config.StatsiteAddr)
if err != nil {
c.Ui.Error(fmt.Sprintf("Failed to start statsite sink. Got: %s", err))
return 1
}
fanout := metrics.FanoutSink{inm, sink}
metrics.NewGlobal(metricsConf, fanout)
} else {
metricsConf.EnableHostname = false
metrics.NewGlobal(metricsConf, inm)
}
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// Create the agent
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if err := c.setupAgent(config, logOutput, logWriter); err != nil {
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return 1
}
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defer c.agent.Shutdown()
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if c.rpcServer != nil {
defer c.rpcServer.Shutdown()
}
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if c.httpServer != nil {
defer c.httpServer.Shutdown()
}
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// Join startup nodes if specified
if err := c.startupJoin(config); err != nil {
c.Ui.Error(err.Error())
return 1
}
// Register the services
for _, service := range config.Services {
ns := service.NodeService()
chkType := service.CheckType()
if err := c.agent.AddService(ns, chkType); err != nil {
c.Ui.Error(fmt.Sprintf("Failed to register service '%s': %v", service.Name, err))
return 1
}
}
// Register the checks
for _, check := range config.Checks {
health := check.HealthCheck(config.NodeName)
chkType := &check.CheckType
if err := c.agent.AddCheck(health, chkType); err != nil {
c.Ui.Error(fmt.Sprintf("Failed to register check '%s': %v %v", check.Name, err, check))
return 1
}
}
// Let the agent know we've finished registration
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c.agent.StartSync()
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c.Ui.Output("Consul agent running!")
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c.Ui.Info(fmt.Sprintf(" Node name: '%s'", config.NodeName))
c.Ui.Info(fmt.Sprintf(" Datacenter: '%s'", config.Datacenter))
c.Ui.Info(fmt.Sprintf(" Server: %v (bootstrap: %v)", config.Server, config.Bootstrap))
c.Ui.Info(fmt.Sprintf(" Client Addr: %v (HTTP: %d, DNS: %d, RPC: %d)", config.ClientAddr,
config.Ports.HTTP, config.Ports.DNS, config.Ports.RPC))
c.Ui.Info(fmt.Sprintf("Cluster Addr: %v (LAN: %d, WAN: %d)", config.AdvertiseAddr,
config.Ports.SerfLan, config.Ports.SerfWan))
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// Enable log streaming
c.Ui.Info("")
c.Ui.Output("Log data will now stream in as it occurs:\n")
logGate.Flush()
// Wait for exit
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return c.handleSignals(config)
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}
// handleSignals blocks until we get an exit-causing signal
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func (c *Command) handleSignals(config *Config) int {
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signalCh := make(chan os.Signal, 4)
signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM, syscall.SIGHUP)
// Wait for a signal
WAIT:
var sig os.Signal
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select {
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case s := <-signalCh:
sig = s
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case <-c.ShutdownCh:
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sig = os.Interrupt
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case <-c.agent.ShutdownCh():
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// Agent is already shutdown!
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return 0
}
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c.Ui.Output(fmt.Sprintf("Caught signal: %v", sig))
// Check if this is a SIGHUP
if sig == syscall.SIGHUP {
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config = c.handleReload(config)
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goto WAIT
}
// Check if we should do a graceful leave
graceful := false
if sig == os.Interrupt && !config.SkipLeaveOnInt {
graceful = true
} else if sig == syscall.SIGTERM && config.LeaveOnTerm {
graceful = true
}
// Bail fast if not doing a graceful leave
if !graceful {
return 1
}
// Attempt a graceful leave
gracefulCh := make(chan struct{})
c.Ui.Output("Gracefully shutting down agent...")
go func() {
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if err := c.agent.Leave(); err != nil {
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c.Ui.Error(fmt.Sprintf("Error: %s", err))
return
}
close(gracefulCh)
}()
// Wait for leave or another signal
select {
case <-signalCh:
return 1
case <-time.After(gracefulTimeout):
return 1
case <-gracefulCh:
return 0
}
}
// handleReload is invoked when we should reload our configs, e.g. SIGHUP
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func (c *Command) handleReload(config *Config) *Config {
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c.Ui.Output("Reloading configuration...")
newConf := c.readConfig()
if newConf == nil {
c.Ui.Error(fmt.Sprintf("Failed to reload configs"))
return config
}
// Change the log level
minLevel := logutils.LogLevel(strings.ToUpper(newConf.LogLevel))
if ValidateLevelFilter(minLevel, c.logFilter) {
c.logFilter.SetMinLevel(minLevel)
} else {
c.Ui.Error(fmt.Sprintf(
"Invalid log level: %s. Valid log levels are: %v",
minLevel, c.logFilter.Levels))
// Keep the current log level
newConf.LogLevel = config.LogLevel
}
// Bulk update the services and checks
c.agent.PauseSync()
defer c.agent.ResumeSync()
// Deregister the old services
for _, service := range config.Services {
ns := service.NodeService()
c.agent.RemoveService(ns.ID)
}
// Deregister the old checks
for _, check := range config.Checks {
health := check.HealthCheck(config.NodeName)
c.agent.RemoveCheck(health.CheckID)
}
// Register the services
for _, service := range newConf.Services {
ns := service.NodeService()
chkType := service.CheckType()
if err := c.agent.AddService(ns, chkType); err != nil {
c.Ui.Error(fmt.Sprintf("Failed to register service '%s': %v", service.Name, err))
}
}
// Register the checks
for _, check := range newConf.Checks {
health := check.HealthCheck(config.NodeName)
chkType := &check.CheckType
if err := c.agent.AddCheck(health, chkType); err != nil {
c.Ui.Error(fmt.Sprintf("Failed to register check '%s': %v %v", check.Name, err, check))
}
}
return newConf
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}
func (c *Command) Synopsis() string {
return "Runs a Consul agent"
}
func (c *Command) Help() string {
helpText := `
Usage: consul agent [options]
Starts the Consul agent and runs until an interrupt is received. The
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agent represents a single node in a cluster.
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Options:
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-bootstrap Sets server to bootstrap mode
-bind=0.0.0.0 Sets the bind address for cluster communication
-client=127.0.0.1 Sets the address to bind for client access.
This includes RPC, DNS and HTTP
-config-file=foo Path to a JSON file to read configuration from.
This can be specified multiple times.
-config-dir=foo Path to a directory to read configuration files
from. This will read every file ending in ".json"
as configuration in this directory in alphabetical
order.
-data-dir=path Path to a data directory to store agent state
-dc=east-aws Datacenter of the agent
-join=1.2.3.4 Address of an agent to join at start time.
Can be specified multiple times.
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-log-level=info Log level of the agent.
-node=hostname Name of this node. Must be unique in the cluster
-protocol=N Sets the protocol version. Defaults to latest.
-server Switches agent to server mode.
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-ui-dir=path Path to directory containing the Web UI resources
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`
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return strings.TrimSpace(helpText)
}