/
agent.go
374 lines (333 loc) · 11.2 KB
/
agent.go
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// Copyright 2012-2020 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.
package unit
import (
"io/ioutil"
"os"
"path"
"runtime"
"strings"
"time"
"github.com/juju/clock"
"github.com/juju/cmd"
"github.com/juju/errors"
"github.com/juju/featureflag"
"github.com/juju/gnuflag"
"github.com/juju/loggo"
"github.com/juju/names/v4"
"github.com/juju/utils/v2/voyeur"
"github.com/juju/worker/v2"
"github.com/juju/worker/v2/dependency"
"github.com/prometheus/client_golang/prometheus"
"github.com/juju/juju/agent"
"github.com/juju/juju/api/base"
"github.com/juju/juju/api/uniter"
k8sconstants "github.com/juju/juju/caas/kubernetes/provider/constants"
jujucmd "github.com/juju/juju/cmd"
"github.com/juju/juju/cmd/jujud/agent/addons"
"github.com/juju/juju/cmd/jujud/agent/agentconf"
"github.com/juju/juju/cmd/jujud/agent/engine"
agenterrors "github.com/juju/juju/cmd/jujud/agent/errors"
"github.com/juju/juju/cmd/k8sagent/utils"
"github.com/juju/juju/core/machinelock"
jnames "github.com/juju/juju/juju/names"
jujuversion "github.com/juju/juju/version"
jworker "github.com/juju/juju/worker"
"github.com/juju/juju/worker/introspection"
"github.com/juju/juju/worker/logsender"
uniterworker "github.com/juju/juju/worker/uniter"
)
var logger = loggo.GetLogger("juju.cmd.k8sagent.unit")
type k8sUnitAgent struct {
cmd.CommandBase
agentconf.AgentConf
configChangedVal *voyeur.Value
clk clock.Clock
runner *worker.Runner
bufferedLogger *logsender.BufferedLogWriter
setupLogging func(agent.Config) error
ctx *cmd.Context
dead chan struct{}
errReason error
machineLock machinelock.Lock
prometheusRegistry *prometheus.Registry
fileReaderWriter utils.FileReaderWriter
environment utils.Environment
charmModifiedVersion int
envVars []string
}
// New creates k8sagent unit command.
func New(ctx *cmd.Context, bufferedLogger *logsender.BufferedLogWriter) (cmd.Command, error) {
prometheusRegistry, err := addons.NewPrometheusRegistry()
if err != nil {
return nil, errors.Trace(err)
}
return &k8sUnitAgent{
AgentConf: agentconf.NewAgentConf(""),
configChangedVal: voyeur.NewValue(true),
ctx: ctx,
clk: clock.WallClock,
dead: make(chan struct{}),
bufferedLogger: bufferedLogger,
prometheusRegistry: prometheusRegistry,
fileReaderWriter: utils.NewFileReaderWriter(),
environment: utils.NewEnvironment(),
}, nil
}
// Info returns a description of the command.
func (c *k8sUnitAgent) Info() *cmd.Info {
return jujucmd.Info(&cmd.Info{
Name: "unit",
Purpose: "starting a k8s agent",
})
}
// SetFlags implements Command.
func (c *k8sUnitAgent) SetFlags(f *gnuflag.FlagSet) {
c.AgentConf.AddFlags(f)
f.IntVar(&c.charmModifiedVersion, "charm-modified-version", -1, "charm modified version to validate downloaded charm is for the provided infrastructure")
f.Var(cmd.NewAppendStringsValue(&c.envVars), "append-env", "can be specified multiple times and with the form ENV_VAR=VALUE where VALUE can be empty or contain unexpanded variables using $OTHER_ENV")
}
func (c *k8sUnitAgent) CharmModifiedVersion() int {
return c.charmModifiedVersion
}
func (c *k8sUnitAgent) ensureAgentConf(dataDir string) error {
templateConfigPath := path.Join(dataDir, k8sconstants.TemplateFileNameAgentConf)
logger.Debugf("template config path %s", templateConfigPath)
config, err := agent.ReadConfig(templateConfigPath)
if err != nil {
return errors.Annotate(err, "reading template agent config file")
}
unitTag := config.Tag()
configPath := agent.ConfigPath(dataDir, unitTag)
logger.Debugf("config path %s", configPath)
configDir := path.Dir(configPath)
if err := os.MkdirAll(configDir, 0755); err != nil {
return errors.Annotatef(err, "making agent directory %q", configDir)
}
configBytes, err := config.Render()
if err != nil {
return errors.Trace(err)
}
if err := ioutil.WriteFile(configPath, configBytes, 0644); err != nil {
return errors.Annotate(err, "writing agent config file")
}
if err := c.ReadConfig(unitTag.String()); err != nil {
return errors.Annotate(err, "reading agent config file")
}
return nil
}
// Init initializes the command for running.
func (c *k8sUnitAgent) Init(args []string) error {
if err := c.AgentConf.CheckArgs(args); err != nil {
return err
}
// Append environment with passed in values.
for _, e := range c.envVars {
kv := strings.SplitN(e, "=", 2)
k, v := "", ""
switch len(kv) {
case 1:
k = kv[0]
case 2:
k = kv[0]
v = kv[1]
default:
return errors.NotValidf("invalid K=V pair for --append-env")
}
if v == "" {
err := c.environment.Unsetenv(k)
if err != nil {
return errors.Trace(err)
}
} else {
err := c.environment.Setenv(k, c.environment.ExpandEnv(v))
if err != nil {
return errors.Trace(err)
}
}
}
c.runner = worker.NewRunner(worker.RunnerParams{
IsFatal: agenterrors.IsFatal,
MoreImportant: agenterrors.MoreImportant,
RestartDelay: jworker.RestartDelay,
})
dataDir := c.DataDir()
if err := c.ensureAgentConf(dataDir); err != nil {
return errors.Annotate(err, "ensuring agent conf file")
}
unitTag, ok := c.CurrentConfig().Tag().(names.UnitTag)
if !ok {
return errors.NotValidf("expected a unit tag; got %q", unitTag)
}
srcDir := path.Dir(os.Args[0])
if err := c.ensureToolSymlinks(srcDir, dataDir, unitTag); err != nil {
return errors.Annotate(err, "ensuring agent conf file")
}
return nil
}
func (c *k8sUnitAgent) ensureToolSymlinks(srcPath, dataDir string, unitTag names.UnitTag) error {
// Setup tool symlinks
uniterPaths := uniterworker.NewPaths(dataDir, unitTag, nil)
toolsDir := uniterPaths.GetToolsDir()
err := c.fileReaderWriter.MkdirAll(toolsDir, 0755)
if err != nil {
return errors.Annotate(err, "creating tools dir")
}
for _, link := range []string{
jnames.K8sAgent,
jnames.JujuRun,
jnames.JujuIntrospect,
} {
if err = c.fileReaderWriter.Symlink(path.Join(srcPath, jnames.K8sAgent), path.Join(toolsDir, link)); err != nil {
return errors.Annotatef(err, "ensuring symlink %q", link)
}
}
if err = c.fileReaderWriter.Symlink(path.Join(srcPath, jnames.Jujuc), path.Join(toolsDir, jnames.Jujuc)); err != nil {
return errors.Annotatef(err, "ensuring symlink %q", jnames.Jujuc)
}
return nil
}
// Wait waits for the k8s unit agent to finish.
func (c *k8sUnitAgent) Wait() error {
<-c.dead
return c.errReason
}
// Stop implements Worker.
func (c *k8sUnitAgent) Stop() error {
c.runner.Kill()
return c.Wait()
}
// Done signals the machine agent is finished
func (c *k8sUnitAgent) Done(err error) {
c.errReason = err
close(c.dead)
}
// Tag implements Agent.
func (c *k8sUnitAgent) Tag() names.UnitTag {
return c.CurrentConfig().Tag().(names.UnitTag)
}
// ChangeConfig implements Agent.
func (c *k8sUnitAgent) ChangeConfig(mutate agent.ConfigMutator) error {
err := c.AgentConf.ChangeConfig(mutate)
c.configChangedVal.Set(true)
return errors.Trace(err)
}
// Workers returns a dependency.Engine running the k8s unit agent's responsibilities.
func (c *k8sUnitAgent) workers() (worker.Worker, error) {
probePort := os.Getenv(k8sconstants.EnvAgentHTTPProbePort)
if probePort == "" {
return nil, errors.NotValidf("env %s missing", k8sconstants.EnvAgentHTTPProbePort)
}
updateAgentConfLogging := func(loggingConfig string) error {
return c.AgentConf.ChangeConfig(func(setter agent.ConfigSetter) error {
setter.SetLoggingConfig(loggingConfig)
return nil
})
}
agentConfig := c.AgentConf.CurrentConfig()
cfg := manifoldsConfig{
Agent: agent.APIHostPortsSetter{Agent: c},
LogSource: c.bufferedLogger.Logs(),
LeadershipGuarantee: 30 * time.Second,
AgentConfigChanged: c.configChangedVal,
ValidateMigration: c.validateMigration,
PrometheusRegisterer: c.prometheusRegistry,
UpdateLoggerConfig: updateAgentConfLogging,
PreviousAgentVersion: agentConfig.UpgradedToVersion(),
ProbePort: probePort,
MachineLock: c.machineLock,
Clock: c.clk,
CharmModifiedVersion: c.CharmModifiedVersion(),
}
manifolds := Manifolds(cfg)
engine, err := dependency.NewEngine(engine.DependencyEngineConfig())
if err != nil {
return nil, err
}
if err := dependency.Install(engine, manifolds); err != nil {
if err := worker.Stop(engine); err != nil {
logger.Errorf("while stopping engine with bad manifolds: %v", err)
}
return nil, err
}
if err := addons.StartIntrospection(addons.IntrospectionConfig{
Agent: c,
Engine: engine,
MachineLock: c.machineLock,
NewSocketName: addons.DefaultIntrospectionSocketName,
PrometheusGatherer: c.prometheusRegistry,
WorkerFunc: introspection.NewWorker,
}); err != nil {
// If the introspection worker failed to start, we just log error
// but continue. It is very unlikely to happen in the real world
// as the only issue is connecting to the abstract domain socket
// and the agent is controlled by by the OS to only have one.
logger.Errorf("failed to start introspection worker: %v", err)
}
return engine, nil
}
func (c *k8sUnitAgent) Run(ctx *cmd.Context) (err error) {
defer c.Done(err)
ctx.Infof("starting k8sagent unit command")
agentConfig := c.CurrentConfig()
machineLock, err := machinelock.New(machinelock.Config{
AgentName: c.Tag().String(),
Clock: c.clk,
Logger: loggo.GetLogger("juju.machinelock"),
LogFilename: agent.MachineLockLogFilename(agentConfig),
})
// There will only be an error if the required configuration
// values are not passed in.
if err != nil {
return errors.Trace(err)
}
c.machineLock = machineLock
ctx.Infof("k8sagent unit %q start (%s [%s])", c.Tag().String(), jujuversion.Current, runtime.Compiler)
if flags := featureflag.String(); flags != "" {
ctx.Warningf("developer feature flags enabled: %s", flags)
}
c.runner.StartWorker("unit", c.workers)
return AgentDone(logger, c.runner.Wait())
}
// validateMigration is called by the migrationminion to help check
// that the agent will be ok when connected to a new controller.
func (c *k8sUnitAgent) validateMigration(apiCaller base.APICaller) error {
// TODO(mjs) - more extensive checks to come.
tag := c.CurrentConfig().Tag()
unitTag, ok := tag.(names.UnitTag)
if !ok {
return errors.NotValidf("expected a unit tag; got %q", tag)
}
facade := uniter.NewState(apiCaller, unitTag)
_, err := facade.Unit(unitTag)
if err != nil {
return errors.Trace(err)
}
model, err := facade.Model()
if err != nil {
return errors.Trace(err)
}
curModelUUID := c.CurrentConfig().Model().Id()
newModelUUID := model.UUID
if newModelUUID != curModelUUID {
return errors.Errorf("model mismatch when validating: got %q, expected %q",
newModelUUID, curModelUUID)
}
return nil
}
// AgentDone processes the error returned by an exiting agent.
func AgentDone(logger loggo.Logger, err error) error {
err = errors.Cause(err)
switch err {
case jworker.ErrTerminateAgent:
// These errors are swallowed here because we want to exit
// the agent process without error, to avoid the init system
// restarting us.
err = nil
}
if err == jworker.ErrRestartAgent {
// This does not seems to happen for k8s units.
logger.Warningf("agent restarting")
}
return err
}