Added config-file flag to accept file based input params

.changelog/164.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+Adds a flag to the existing consul-dataplane command `config-file` to support reading configurations
+from a JSON file.
+```

cmd/consul-dataplane/config.go

@@ -0,0 +1,294 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/hashicorp/consul-dataplane/pkg/consuldp"
+)
+
+type FlagOpts struct {
+	printVersion bool
+
+	addresses           string
+	grpcPort            int
+	serverWatchDisabled bool
+
+	tlsDisabled           bool
+	tlsCACertsPath        string
+	tlsServerName         string
+	tlsCertFile           string
+	tlsKeyFile            string
+	tlsInsecureSkipVerify bool
+
+	logLevel string
+	logJSON  bool
+
+	nodeName      string
+	nodeID        string
+	serviceID     string
+	serviceIDPath string
+	namespace     string
+	partition     string
+
+	credentialType       string
+	token                string
+	loginAuthMethod      string
+	loginNamespace       string
+	loginPartition       string
+	loginDatacenter      string
+	loginBearerToken     string
+	loginBearerTokenPath string
+	loginMeta            map[string]string
+
+	useCentralTelemetryConfig bool
+
+	promRetentionTime     time.Duration
+	promCACertsPath       string
+	promKeyFile           string
+	promCertFile          string
+	promServiceMetricsURL string
+	promScrapePath        string
+	promMergePort         int
+
+	adminBindAddr         string
+	adminBindPort         int
+	readyBindAddr         string
+	readyBindPort         int
+	envoyConcurrency      int
+	envoyDrainTimeSeconds int
+	envoyDrainStrategy    string
+
+	xdsBindAddr string
+	xdsBindPort int
+
+	consulDNSBindAddr string
+	consulDNSPort     int
+
+	shutdownDrainListenersEnabled bool
+	shutdownGracePeriodSeconds    int
+	gracefulShutdownPath          string
+	gracefulPort                  int
+
+	dumpEnvoyConfigOnExitEnabled bool
+
+	configFile string
+}
+
+const (
+	DefaultGRPCPort            = 8502
+	DefaultServerWatchDisabled = false
+
+	DefaultTLSDisabled           = false
+	DefaultTLSInsecureSkipVerify = false
+
+	DefaultDNSBindAddr = "127.0.0.1"
+	DefaultDNSBindPort = -1
+
+	DefaultXDSBindAddr = "127.0.0.1"
+	DefaultXDSBindPort = 0
+
+	DefaultLogLevel = "info"
+	DefaultLogJSON  = false
+
+	DefaultEnvoyAdminBindAddr                 = "127.0.0.1"
+	DefaultEnvoyAdminBindPort                 = 19000
+	DefaultEnvoyReadyBindPort                 = 0
+	DefaultEnvoyConcurrency                   = 2
+	DefaultEnvoyDrainTimeSeconds              = 30
+	DefaultEnvoyDrainStrategy                 = "immediate"
+	DefaultEnvoyShutdownDrainListenersEnabled = false
+	DefaultEnvoyShutdownGracePeriodSeconds    = 0
+	DefaultGracefulShutdownPath               = "/graceful_shutdown"
+	DefaultGracefulPort                       = 20300
+	DefaultDumpEnvoyConfigOnExitEnabled       = false
+
+	DefaultUseCentralTelemetryConfig = true
+	DefaultPromRetentionTime         = 60 * time.Second
+	DefaultPromScrapePath            = "/metrics"
+	DefaultPromMergePort             = 20100
+)
+
+// buildDataplaneConfig builds the necessary config needed for the
+// dataplane to start. We begin with the default version of the dataplane
+// config(with the default values) followed by merging the file based
+// config generated from the `-config-file` input into it.
+// Since values given via CLI flags take the most precedence, we finally
+// merge the config generated from the flags into the previously
+// generated/merged config
+func (f *FlagOpts) buildDataplaneConfig() (*consuldp.Config, error) {
+	var consuldpConfig, consuldpCfgFromFlags *consuldp.Config
+
+	consuldpConfig = buildDefaultConsulDPConfig()
+	consuldpCfgFromFlags = f.buildConfig()
+
+	if f.configFile != "" {
+		consuldpCfgFromFile, err := f.buildConfigFromFile()
+		if err != nil {
+			return nil, err
+		}
+
+		mergeConfigs(consuldpConfig, consuldpCfgFromFile)
+	}
+
+	mergeConfigs(consuldpConfig, consuldpCfgFromFlags)
+
+	return consuldpConfig, nil
+}
+
+// Constructs a config based on the values present in the config json file
+func (f *FlagOpts) buildConfigFromFile() (*consuldp.Config, error) {
+	var cfg *consuldp.Config
+	data, err := os.ReadFile(f.configFile)
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(data, &cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
+}
+
+// Constructs a config based on the values given via the CLI flags
+func (f *FlagOpts) buildConfig() *consuldp.Config {
+	return &consuldp.Config{
+		Consul: &consuldp.ConsulConfig{
+			Addresses: f.addresses,
+			GRPCPort:  f.grpcPort,
+			Credentials: &consuldp.CredentialsConfig{
+				Type: consuldp.CredentialsType(f.credentialType),
+				Static: consuldp.StaticCredentialsConfig{
+					Token: f.token,
+				},
+				Login: consuldp.LoginCredentialsConfig{
+					AuthMethod:      f.loginAuthMethod,
+					Namespace:       f.loginNamespace,
+					Partition:       f.loginPartition,
+					Datacenter:      f.loginDatacenter,
+					BearerToken:     f.loginBearerToken,
+					BearerTokenPath: f.loginBearerTokenPath,
+					Meta:            f.loginMeta,
+				},
+			},
+			ServerWatchDisabled: f.serverWatchDisabled,
+			TLS: &consuldp.TLSConfig{
+				Disabled:           f.tlsDisabled,
+				CACertsPath:        f.tlsCACertsPath,
+				ServerName:         f.tlsServerName,
+				CertFile:           f.tlsCertFile,
+				KeyFile:            f.tlsKeyFile,
+				InsecureSkipVerify: f.tlsInsecureSkipVerify,
+			},
+		},
+		Service: &consuldp.ServiceConfig{
+			NodeName:  f.nodeName,
+			NodeID:    f.nodeID,
+			ServiceID: f.serviceID,
+			Namespace: f.namespace,
+			Partition: f.partition,
+		},
+		Logging: &consuldp.LoggingConfig{
+			Name:     "consul-dataplane",
+			LogLevel: strings.ToUpper(f.logLevel),
+			LogJSON:  f.logJSON,
+		},
+		Telemetry: &consuldp.TelemetryConfig{
+			UseCentralConfig: f.useCentralTelemetryConfig,
+			Prometheus: consuldp.PrometheusTelemetryConfig{
+				RetentionTime:     f.promRetentionTime,
+				CACertsPath:       f.promCACertsPath,
+				KeyFile:           f.promKeyFile,
+				CertFile:          f.promCertFile,
+				ServiceMetricsURL: f.promServiceMetricsURL,
+				ScrapePath:        f.promScrapePath,
+				MergePort:         f.promMergePort,
+			},
+		},
+		Envoy: &consuldp.EnvoyConfig{
+			AdminBindAddress:              f.adminBindAddr,
+			AdminBindPort:                 f.adminBindPort,
+			ReadyBindAddress:              f.readyBindAddr,
+			ReadyBindPort:                 f.readyBindPort,
+			EnvoyConcurrency:              f.envoyConcurrency,
+			EnvoyDrainTimeSeconds:         f.envoyDrainTimeSeconds,
+			EnvoyDrainStrategy:            f.envoyDrainStrategy,
+			ShutdownDrainListenersEnabled: f.shutdownDrainListenersEnabled,
+			ShutdownGracePeriodSeconds:    f.shutdownGracePeriodSeconds,
+			GracefulShutdownPath:          f.gracefulShutdownPath,
+			GracefulPort:                  f.gracefulPort,
+			DumpEnvoyConfigOnExitEnabled:  f.dumpEnvoyConfigOnExitEnabled,
+			ExtraArgs:                     flag.Args(),
+		},
+		XDSServer: &consuldp.XDSServer{
+			BindAddress: f.xdsBindAddr,
+			BindPort:    f.xdsBindPort,
+		},
+		DNSServer: &consuldp.DNSServerConfig{
+			BindAddr: f.consulDNSBindAddr,
+			Port:     f.consulDNSPort,
+		},
+	}
+}
+
+// Constructs a config with the default values
+func buildDefaultConsulDPConfig() *consuldp.Config {
+	return &consuldp.Config{
+		Consul: &consuldp.ConsulConfig{
+			GRPCPort: DefaultGRPCPort,
+			Credentials: &consuldp.CredentialsConfig{
+				Type:   consuldp.CredentialsType(""),
+				Static: consuldp.StaticCredentialsConfig{},
+				Login: consuldp.LoginCredentialsConfig{
+					Meta: map[string]string{},
+				},
+			},
+			ServerWatchDisabled: DefaultServerWatchDisabled,
+			TLS: &consuldp.TLSConfig{
+				Disabled:           DefaultTLSDisabled,
+				InsecureSkipVerify: DefaultTLSInsecureSkipVerify,
+			},
+		},
+		Service: &consuldp.ServiceConfig{},
+		Logging: &consuldp.LoggingConfig{
+			Name:     "consul-dataplane",
+			LogLevel: strings.ToUpper(DefaultLogLevel),
+			LogJSON:  DefaultLogJSON,
+		},
+		Telemetry: &consuldp.TelemetryConfig{
+			UseCentralConfig: DefaultUseCentralTelemetryConfig,
+			Prometheus: consuldp.PrometheusTelemetryConfig{
+				RetentionTime: DefaultPromRetentionTime,
+				ScrapePath:    DefaultPromScrapePath,
+				MergePort:     DefaultPromMergePort,
+			},
+		},
+		Envoy: &consuldp.EnvoyConfig{
+			AdminBindAddress:              DefaultEnvoyAdminBindAddr,
+			AdminBindPort:                 DefaultEnvoyAdminBindPort,
+			ReadyBindPort:                 DefaultEnvoyReadyBindPort,
+			EnvoyConcurrency:              DefaultEnvoyConcurrency,
+			EnvoyDrainTimeSeconds:         DefaultEnvoyDrainTimeSeconds,
+			EnvoyDrainStrategy:            DefaultEnvoyDrainStrategy,
+			ShutdownDrainListenersEnabled: DefaultEnvoyShutdownDrainListenersEnabled,
+			ShutdownGracePeriodSeconds:    DefaultEnvoyShutdownGracePeriodSeconds,
+			GracefulShutdownPath:          DefaultGracefulShutdownPath,
+			GracefulPort:                  DefaultGracefulPort,
+			DumpEnvoyConfigOnExitEnabled:  DefaultDumpEnvoyConfigOnExitEnabled,
+			ExtraArgs:                     []string{},
+		},
+		XDSServer: &consuldp.XDSServer{
+			BindAddress: DefaultXDSBindAddr,
+			BindPort:    DefaultXDSBindPort,
+		},
+		DNSServer: &consuldp.DNSServerConfig{
+			BindAddr: DefaultDNSBindAddr,
+			Port:     DefaultDNSBindPort,
+		},
+	}
+}