LogDog: Add collector service implementation.

server/internal/logdog/service/service.go

+// Copyright 2016 The Chromium Authors. All rights reserved.

[dnj (Google), 2016/01/21 04:36:25]

Generic LogDog daemon support library. This is pulled out from Collector main
because it is super useful for any LogDog daemons that may exist now or in the
future.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package service
+
+import (
+        "errors"
+        "flag"
+        "net/http"
+        "os"
+        "os/signal"
+        "sync"
+
+        "github.com/luci/luci-go/client/authcli"
+        "github.com/luci/luci-go/common/auth"
+        log "github.com/luci/luci-go/common/logging"
+        "github.com/luci/luci-go/common/logging/gologger"
+        "github.com/luci/luci-go/common/proto/logdog/services"
+        "github.com/luci/luci-go/server/internal/logdog/config"
+        "github.com/luci/luci-go/server/internal/logdog/coordinatorClient"
+        "github.com/luci/luci-go/server/logdog/storage"
+        "github.com/luci/luci-go/server/logdog/storage/bigtable"
+        "golang.org/x/net/context"
+        "google.golang.org/cloud"
+)
+
+var (
+        // ErrInvalidConfig is an error that is returned when the supplied
+        // configuration is invalid.
+        ErrInvalidConfig = errors.New("invalid configuration")
+)
+
+// Service is a base class full of common LogDog service application parameters.
+type Service struct {
+        context.Context
+
+        // UserAgent is the user agent string that will be used for service
+        // communication.
+        UserAgent string
+
+        // ShutdownFunc, if not nil, is a function that will be called when a shutdown
+        // signal is received.
+        ShutdownFunc func()
+
+        // topCancelFunc is the Context cancel function for the top-level application
+        // Context.
+        topCancelFunc func()
+
+        // shutdownMu protects the shutdown variables.
+        shutdownMu    sync.Mutex
+        shutdownFunc  func()
+        shutdownCount int32
+
+        loggingFlags log.Config
+        authFlags    authcli.Flags
+        configFlags  config.Flags
+
+        coordinatorURL            string
+        storageCredentialJSONPath string
+
+        coord  *coordinatorClient.Client
+        config *config.Manager
+}
+
+// New instantiates a new Service.
+func New(c context.Context) *Service {
+        c, cancelFunc := context.WithCancel(c)
+        c = gologger.Use(c)
+
+        return &Service{
+                Context:       c,
+                topCancelFunc: cancelFunc,
+        }
+}
+
+// AddFlags adds standard service flags to the supplied FlagSet.
+func (s *Service) AddFlags(fs *flag.FlagSet) {
+        s.loggingFlags.AddFlags(fs)
+        s.authFlags.Register(fs, auth.Options{
+                Context: s,
+                Logger:  log.Get(s),
+        })
+        s.configFlags.AddToFlagSet(fs)
+
+        fs.StringVar(&s.coordinatorURL, "coordinator-url", "",
+                "The URL of the Coordinator service to use.")
+        fs.StringVar(&s.storageCredentialJSONPath, "storage-credential-json-path", "",
+                "If supplied, the path of a JSON credential file to load and use for storage operations.")
+}
+
+// Run loads the Service's base runtime and invokes the specified run function.
+func (s *Service) Run(f func() error) error {
+        s.Context = s.loggingFlags.Set(s.Context)
+
+        // Configure our signal handler. It will listen for terminating signals and
+        // issue a shutdown signal if one is received.
+        signalC := make(chan os.Signal)
+        go func() {
+                for sig := range signalC {
+                        s.Shutdown()
+                        log.Warningf(log.SetField(s, "signal", sig), "Received close signal. Send again to terminate immediately.")
+                }
+        }()
+        signal.Notify(signalC, os.Interrupt)
+        defer func() {
+                signal.Stop(signalC)
+                close(signalC)
+        }()
+
+        // Setup our Coordinator client.
+        var err error
+        s.coord, err = s.initCoordinatorClient()
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to setup Coordinator client.")
+                return err
+        }
+
+        s.config, err = s.initConfig()
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to setup configuration.")
+                return err
+        }
+
+        return f()
+}
+
+func (s *Service) initCoordinatorClient() (*coordinatorClient.Client, error) {
+        if s.coordinatorURL == "" {
+                log.Errorf(s, "Missing Coordinator URL (-coordinator-url).")
+                return nil, ErrInvalidConfig
+        }
+
+        client, err := s.AuthenticatedClient(func(o *auth.Options) {
+                o.Scopes = coordinatorClient.ServiceScopes
+        })
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to create Coordinator client.")
+                return nil, err
+        }
+
+        return coordinatorClient.New(coordinatorClient.Options{
+                Client:    client,
+                BasePath:  s.coordinatorURL,
+                UserAgent: s.UserAgent,
+        }), nil
+}
+
+func (s *Service) initConfig() (*config.Manager, error) {
+        rt, err := s.AuthenticatedTransport(nil)
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to create config client.")
+                return nil, err
+        }
+
+        s.configFlags.RoundTripper = rt
+        o, err := s.configFlags.CoordinatorOptions(s, s.coord)
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to load configuration parameters.")
+                return nil, err
+        }
+        o.KillFunc = s.Shutdown
+
+        return config.NewManager(s, *o)
+}
+
+// Shutdown issues a shutdown signal to the service.
+func (s *Service) Shutdown() {
+        s.shutdownMu.Lock()
+        defer s.shutdownMu.Unlock()
+
+        if s.shutdownCount > 0 {
+                os.Exit(1)
+        }
+        s.shutdownCount++
+
+        if f := s.shutdownFunc; f != nil {
+                f()
+        } else {
+                s.topCancelFunc()
+        }
+}
+
+// SetShutdownFunc sets the service shutdown function.
+func (s *Service) SetShutdownFunc(f func()) {
+        s.shutdownMu.Lock()
+        defer s.shutdownMu.Unlock()
+        s.shutdownFunc = f
+}
+
+// Config returns the cached service configuration.
+func (s *Service) Config() *services.Config {
+        return s.config.Config()
+}
+
+// Coordinator returns the cached Coordinator client.
+func (s *Service) Coordinator() *coordinatorClient.Client {
+        return s.coord
+}
+
+// Storage instantiates the configured Storage instance.
+func (s *Service) Storage() (storage.Storage, error) {
+        cfg := s.config.Config()
+        if cfg.GetStorage() == nil {
+                log.Errorf(s, "Missing storage configuration.")
+                return nil, ErrInvalidConfig
+        }
+
+        btcfg := cfg.GetStorage().GetBigtable()
+        if btcfg == nil {
+                log.Errorf(s, "Missing BigTable storage configuration")
+                return nil, ErrInvalidConfig
+        }
+
+        // Initialize Storage authentication.
+        a, err := s.Authenticator(func(o *auth.Options) {
+                o.Scopes = bigtable.StorageScopes
+                if s.storageCredentialJSONPath != "" {
+                        o.ServiceAccountJSONPath = s.storageCredentialJSONPath
+                }
+        })
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to create BigTable Authenticator.")
+                return nil, err
+        }
+
+        bt, err := bigtable.New(s, bigtable.Options{
+                Project:  btcfg.Project,
+                Zone:     btcfg.Zone,
+                Cluster:  btcfg.Cluster,
+                LogTable: btcfg.LogTableName,
+                ClientOptions: []cloud.ClientOption{
+                        cloud.WithTokenSource(a.TokenSource()),
+                },
+        })
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to create BigTable instance.")
+                return nil, err
+        }
+        return bt, nil
+}
+
+// Authenticator returns an Authenticator instance. The Authenticator is
+// configured from a base set of Authenticator Options.
+//
+// An optional permutation functon can be provided to modify those Options
+// before the Authenticator is created.
+func (s *Service) Authenticator(f func(o *auth.Options)) (*auth.Authenticator, error) {
+        authOpts, err := s.authFlags.Options()
+        if err != nil {
+                log.Errorf(log.SetError(s, err), "Failed to create authenticator options.")
+                return nil, ErrInvalidConfig
+        }
+        if f != nil {
+                f(&authOpts)
+        }
+        return auth.NewAuthenticator(auth.SilentLogin, authOpts), nil
+}
+
+// AuthenticatedTransport returns an authenticated http.RoundTripper transport.
+// The transport is configured from a base set of Authenticator Options.
+//
+// An optional permutation functon can be provided to modify those Options
+// before the Authenticator is created.
+func (s *Service) AuthenticatedTransport(f func(o *auth.Options)) (http.RoundTripper, error) {
+        a, err := s.Authenticator(f)
+        if err != nil {
+                return nil, err
+        }
+        return a.Transport()
+}
+
+// AuthenticatedClient returns an authenticated http.Client. The Client is
+// configured from a base set of Authenticator Options.
+//
+// An optional permutation functon can be provided to modify those Options
+// before the Authenticator is created.
+func (s *Service) AuthenticatedClient(f func(o *auth.Options)) (*http.Client, error) {
+        a, err := s.Authenticator(f)
+        if err != nil {
+                return nil, err
+        }
+        return a.Client()
+}