Rename prometheus to metrics

CHANGELOG.md

@@ -75,6 +75,11 @@ for specific instructions.
   `loki_tag` is now `logs_instance_tag`, and `backend: loki` is now
   `backend: logs_instance`. (@rfratto)
 
+- [DEPRECATION] The `prometheus` key at the root of the config file has been
+  deprecated in favor of `metrics`. Flag names starting with `prometheus.` have
+  also been deprecated in favor of the same flags with the `metrics.` prefix.
+  (@rfratto)
+
 # v0.18.2 (2021-08-12)
 
 - [BUGFIX] Honor the prefix and remove prefix from consul list results (@mattdurham)

cmd/agent/entrypoint.go

@@ -75,7 +75,7 @@ func NewEntrypoint(logger *util.Logger, cfg *config.Config, reloader Reloader) (
 
 	ep.srv = server.New(prometheus.DefaultRegisterer, logger)
 
-	ep.promMetrics, err = metrics.New(prometheus.DefaultRegisterer, cfg.Prometheus, logger)
+	ep.promMetrics, err = metrics.New(prometheus.DefaultRegisterer, cfg.Metrics, logger)
 	if err != nil {
 		return nil, err
 	}
@@ -121,7 +121,7 @@ func (ep *Entrypoint) ApplyConfig(cfg config.Config) error {
 	}
 
 	// Go through each component and update it.
-	if err := ep.promMetrics.ApplyConfig(cfg.Prometheus); err != nil {
+	if err := ep.promMetrics.ApplyConfig(cfg.Metrics); err != nil {
 		level.Error(ep.log).Log("msg", "failed to update prometheus", "err", err)
 		failed = true
 	}

docs/upgrade-guide/_index.md

@@ -118,6 +118,51 @@ rules:
   verbs: [get, list, watch]
 ```
 
+### Metrics: Deprecation of "prometheus" in config. (Deprecation)
+
+The term `prometheus` in the config has been deprecated of favor of `metrics`. This
+change is to make it clearer when referring to Prometheus or another
+Prometheus-like database, and configuration of Grafana Agent to send metrics to
+one of those systems.
+
+Old configs will continue to work until it is fully deprecated. To migrate your
+config, change the `prometheus` key to `metrics`.
+
+Example old config:
+
+```yaml
+prometheus:
+  configs:
+    - name: default
+      host_filter: false
+      scrape_configs:
+        - job_name: local_scrape
+          static_configs:
+            - targets: ['127.0.0.1:12345']
+              labels:
+                cluster: 'localhost'
+      remote_write:
+        - url: http://localhost:9009/api/prom/push
+```
+
+Example new config:
+
+```yaml
+metrics:
+  configs:
+    - name: default
+      host_filter: false
+      scrape_configs:
+        - job_name: local_scrape
+          static_configs:
+            - targets: ['127.0.0.1:12345']
+              labels:
+                cluster: 'localhost'
+      remote_write:
+        - url: http://localhost:9009/api/prom/push
+```
+
+
 ### Logs: Deprecation of "loki" in config. (Deprecation)
 
 The term `loki` in the config has been deprecated of favor of `logs`. This

pkg/config/config.go

@@ -25,78 +25,102 @@ import (
 // DefaultConfig holds default settings for all the subsystems.
 var DefaultConfig = Config{
 	// All subsystems with a DefaultConfig should be listed here.
-	Prometheus:   metrics.DefaultConfig,
+	Metrics:      metrics.DefaultConfig,
 	Integrations: integrations.DefaultManagerConfig,
 }
 
 // Config contains underlying configurations for the agent
 type Config struct {
 	Server       server.Config              `yaml:"server,omitempty"`
-	Prometheus   metrics.Config             `yaml:"prometheus,omitempty"`
+	Metrics      metrics.Config             `yaml:"metrics,omitempty"`
 	Integrations integrations.ManagerConfig `yaml:"integrations,omitempty"`
 	Tempo        tempo.Config               `yaml:"tempo,omitempty"`
-
-	Logs               *logs.Config `yaml:"logs,omitempty"`
-	Loki               *logs.Config `yaml:"loki,omitempty"` // Deprecated: use Logs instead
-	UsedDeprecatedLoki bool         `yaml:"-"`
+	Logs         *logs.Config               `yaml:"logs,omitempty"`
 
 	// We support a secondary server just for the /-/reload endpoint, since
 	// invoking /-/reload against the primary server can cause the server
 	// to restart.
 	ReloadAddress string `yaml:"-"`
 	ReloadPort    int    `yaml:"-"`
+
+	// Deprecated fields user has used. Generated during UnmarshalYAML.
+	Deprecations []string `yaml:"-"`
 }
 
 // UnmarshalYAML implements yaml.Unmarshaler.
 func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	// Apply defaults to the config from our struct and any defaults inherited
-	// from flags.
+	// from flags before unmarshaling.
 	*c = DefaultConfig
 	util.DefaultConfigFromFlags(c)
 
-	type config Config
-	return unmarshal((*config)(c))
+	type baseConfig Config
+
+	type config struct {
+		baseConfig `yaml:",inline"`
+
+		// Deprecated field names:
+		Prometheus *metrics.Config `yaml:"prometheus,omitempty"`
+		Loki       *logs.Config    `yaml:"loki,omitempty"`
+	}
+
+	var fc config
+	fc.baseConfig = baseConfig(*c)
+
+	if err := unmarshal(&fc); err != nil {
+		return err
+	}
+
+	// Migrate old fields to the new name
+	if fc.Prometheus != nil && fc.Metrics.Unmarshaled && fc.Prometheus.Unmarshaled {
+		return fmt.Errorf("at most one of prometheus and metrics should be specified")
+	} else if fc.Prometheus != nil && fc.Prometheus.Unmarshaled {
+		fc.Deprecations = append(fc.Deprecations, "`prometheus` has been deprecated in favor of `metrics`")
+		fc.Metrics = *fc.Prometheus
+		fc.Prometheus = nil
+	}
+
+	if fc.Logs != nil && fc.Loki != nil {
+		return fmt.Errorf("at most one of loki and logs should be specified")
+	} else if fc.Logs == nil && fc.Loki != nil {
+		fc.Deprecations = append(fc.Deprecations, "`loki` has been deprecated in favor of `logs`")
+		fc.Logs = fc.Loki
+		fc.Loki = nil
+	}
+
+	*c = Config(fc.baseConfig)
+	return nil
 }
 
 // LogDeprecations will log use of any deprecated fields to l as warn-level
 // messages.
 func (c *Config) LogDeprecations(l log.Logger) {
-	if c.UsedDeprecatedLoki {
-		level.Warn(l).Log("msg", "DEPRECATION NOTICE: `loki` is deprecated in favor of `logs`")
+	for _, d := range c.Deprecations {
+		level.Warn(l).Log("msg", fmt.Sprintf("DEPRECATION NOTICE: %s", d))
 	}
 }
 
 // ApplyDefaults sets default values in the config
 func (c *Config) ApplyDefaults() error {
-	if err := c.Prometheus.ApplyDefaults(); err != nil {
+	if err := c.Metrics.ApplyDefaults(); err != nil {
 		return err
 	}
 
-	if c.Logs != nil && c.Loki != nil {
-		return fmt.Errorf("at most one of loki and logs should be specified")
-	}
-
-	if c.Logs == nil && c.Loki != nil {
-		c.Logs = c.Loki
-		c.Loki = nil
-		c.UsedDeprecatedLoki = true
-	}
-
-	if err := c.Integrations.ApplyDefaults(&c.Prometheus); err != nil {
+	if err := c.Integrations.ApplyDefaults(&c.Metrics); err != nil {
 		return err
 	}
 
-	c.Prometheus.ServiceConfig.Lifecycler.ListenPort = c.Server.GRPCListenPort
+	c.Metrics.ServiceConfig.Lifecycler.ListenPort = c.Server.GRPCListenPort
 	c.Integrations.ListenPort = c.Server.HTTPListenPort
 	c.Integrations.ListenHost = c.Server.HTTPListenAddress
 
 	c.Integrations.ServerUsingTLS = c.Server.HTTPTLSConfig.TLSKeyPath != "" && c.Server.HTTPTLSConfig.TLSCertPath != ""
 
 	if len(c.Integrations.PrometheusRemoteWrite) == 0 {
-		c.Integrations.PrometheusRemoteWrite = c.Prometheus.Global.RemoteWrite
+		c.Integrations.PrometheusRemoteWrite = c.Metrics.Global.RemoteWrite
 	}
 
-	c.Integrations.PrometheusGlobalConfig = c.Prometheus.Global.Prometheus
+	c.Integrations.PrometheusGlobalConfig = c.Metrics.Global.Prometheus
 
 	// since the Tempo config might rely on an existing Loki config
 	// this check is made here to look for cross config issues before we attempt to load
@@ -111,7 +135,7 @@ func (c *Config) ApplyDefaults() error {
 func (c *Config) RegisterFlags(f *flag.FlagSet) {
 	c.Server.MetricsNamespace = "agent"
 	c.Server.RegisterInstrumentation = true
-	c.Prometheus.RegisterFlags(f)
+	c.Metrics.RegisterFlags(f)
 	c.Server.RegisterFlags(f)
 
 	f.StringVar(&c.ReloadAddress, "reload-addr", "127.0.0.1", "address to expose a secondary server for /-/reload on.")

pkg/config/config_test.go

@@ -30,9 +30,9 @@ prometheus:
 		return LoadBytes([]byte(cfg), false, c)
 	})
 	require.NoError(t, err)
-	require.NotEmpty(t, c.Prometheus.ServiceConfig.Lifecycler.InfNames)
-	require.NotZero(t, c.Prometheus.ServiceConfig.Lifecycler.NumTokens)
-	require.NotZero(t, c.Prometheus.ServiceConfig.Lifecycler.HeartbeatPeriod)
+	require.NotEmpty(t, c.Metrics.ServiceConfig.Lifecycler.InfNames)
+	require.NotZero(t, c.Metrics.ServiceConfig.Lifecycler.NumTokens)
+	require.NotZero(t, c.Metrics.ServiceConfig.Lifecycler.HeartbeatPeriod)
 	require.True(t, c.Server.RegisterInstrumentation)
 }
 
@@ -55,7 +55,7 @@ prometheus:
 		return LoadBytes([]byte(cfg), false, c)
 	})
 	require.NoError(t, err)
-	require.Equal(t, expect, c.Prometheus.Global)
+	require.Equal(t, expect, c.Metrics.Global)
 }
 
 func TestConfig_OverrideByEnvironmentOnLoad(t *testing.T) {
@@ -78,7 +78,7 @@ prometheus:
 		return LoadBytes([]byte(cfg), true, c)
 	})
 	require.NoError(t, err)
-	require.Equal(t, expect, c.Prometheus.Global)
+	require.Equal(t, expect, c.Metrics.Global)
 }
 
 func TestConfig_OverrideByEnvironmentOnLoad_NoDigits(t *testing.T) {
@@ -95,7 +95,7 @@ prometheus:
 		return LoadBytes([]byte(cfg), true, c)
 	})
 	require.NoError(t, err)
-	require.Equal(t, expect, c.Prometheus.Global.Prometheus.ExternalLabels)
+	require.Equal(t, expect, c.Metrics.Global.Prometheus.ExternalLabels)
 }
 
 func TestConfig_FlagsAreAccepted(t *testing.T) {
@@ -115,7 +115,7 @@ prometheus:
 		return LoadBytes([]byte(cfg), false, c)
 	})
 	require.NoError(t, err)
-	require.Equal(t, "/tmp/wal", c.Prometheus.WALDir)
+	require.Equal(t, "/tmp/wal", c.Metrics.WALDir)
 }
 
 func TestConfig_StrictYamlParsing(t *testing.T) {
@@ -148,7 +148,7 @@ func TestConfig_Defaults(t *testing.T) {
 	err := LoadBytes([]byte(`{}`), false, &c)
 	require.NoError(t, err)
 
-	require.Equal(t, metrics.DefaultConfig, c.Prometheus)
+	require.Equal(t, metrics.DefaultConfig, c.Metrics)
 	require.Equal(t, integrations.DefaultManagerConfig, c.Integrations)
 }
 
@@ -216,9 +216,51 @@ loki:
 	require.NoError(t, LoadBytes([]byte(input), false, &cfg))
 	require.NoError(t, cfg.ApplyDefaults())
 
-	require.Nil(t, cfg.Loki)
 	require.NotNil(t, cfg.Logs)
 	require.Equal(t, "foo", cfg.Logs.Configs[0].Name)
+	require.Equal(t, []string{"`loki` has been deprecated in favor of `logs`"}, cfg.Deprecations)
+}
+
+func TestConfig_PrometheusNonNil(t *testing.T) {
+	tt := []struct {
+		name  string
+		input string
+	}{
+		{
+			name:  "missing",
+			input: `{}`,
+		},
+		{
+			name:  "null",
+			input: `prometheus: null`,
+		},
+	}
+
+	for _, tc := range tt {
+		t.Run(tc.name, func(t *testing.T) {
+			var cfg Config
+			require.NoError(t, LoadBytes([]byte(tc.input), false, &cfg))
+			require.NoError(t, cfg.ApplyDefaults())
+
+			require.NotNil(t, cfg.Metrics)
+		})
+	}
+}
+
+func TestConfig_PrometheusNameMigration(t *testing.T) {
+	input := util.Untab(`
+prometheus:
+	wal_directory: /tmp
+  configs:
+  - name: default
+`)
+	var cfg Config
+	require.NoError(t, LoadBytes([]byte(input), false, &cfg))
+	require.NoError(t, cfg.ApplyDefaults())
+
+	require.Equal(t, "default", cfg.Metrics.Configs[0].Name)
+	require.Equal(t, "/tmp", cfg.Metrics.WALDir)
+	require.Equal(t, []string{"`prometheus` has been deprecated in favor of `metrics`"}, cfg.Deprecations)
 }
 
 func TestConfig_TempoLokiFailsValidation(t *testing.T) {

pkg/metrics/agent.go

@@ -43,11 +43,16 @@ type Config struct {
 	Configs                []instance.Config     `yaml:"configs,omitempty,omitempty"`
 	InstanceRestartBackoff time.Duration         `yaml:"instance_restart_backoff,omitempty"`
 	InstanceMode           instance.Mode         `yaml:"instance_mode,omitempty"`
+
+	// Unmarshaled is true when the Config was unmarshaled from YAML.
+	Unmarshaled bool `yaml:"-"`
 }
 
 // UnmarshalYAML implements yaml.Unmarshaler.
 func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	*c = DefaultConfig
+	util.DefaultConfigFromFlags(c)
+	c.Unmarshaled = true
 
 	type plain Config
 	err := unmarshal((*plain)(c))
@@ -97,13 +102,21 @@ func (c *Config) ApplyDefaults() error {
 
 // RegisterFlags defines flags corresponding to the Config.
 func (c *Config) RegisterFlags(f *flag.FlagSet) {
-	f.StringVar(&c.WALDir, "prometheus.wal-directory", "", "base directory to store the WAL in")
-	f.DurationVar(&c.WALCleanupAge, "prometheus.wal-cleanup-age", DefaultConfig.WALCleanupAge, "remove abandoned (unused) WALs older than this")
-	f.DurationVar(&c.WALCleanupPeriod, "prometheus.wal-cleanup-period", DefaultConfig.WALCleanupPeriod, "how often to check for abandoned WALs")
-	f.DurationVar(&c.InstanceRestartBackoff, "prometheus.instance-restart-backoff", DefaultConfig.InstanceRestartBackoff, "how long to wait before restarting a failed Prometheus instance")
+	c.RegisterFlagsWithPrefix("metrics.", f)
+
+	// Register deprecated flag names.
+	c.RegisterFlagsWithPrefix("prometheus.", f)
+}
+
+// RegisterFlagsWithPrefix defines flags with the provided prefix.
+func (c *Config) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
+	f.StringVar(&c.WALDir, prefix+"wal-directory", "", "base directory to store the WAL in")
+	f.DurationVar(&c.WALCleanupAge, prefix+"wal-cleanup-age", DefaultConfig.WALCleanupAge, "remove abandoned (unused) WALs older than this")
+	f.DurationVar(&c.WALCleanupPeriod, prefix+"wal-cleanup-period", DefaultConfig.WALCleanupPeriod, "how often to check for abandoned WALs")
+	f.DurationVar(&c.InstanceRestartBackoff, prefix+"instance-restart-backoff", DefaultConfig.InstanceRestartBackoff, "how long to wait before restarting a failed Prometheus instance")
 
-	c.ServiceConfig.RegisterFlagsWithPrefix("prometheus.service.", f)
-	c.ServiceClientConfig.RegisterFlags(f)
+	c.ServiceConfig.RegisterFlagsWithPrefix(prefix+"service.", f)
+	c.ServiceClientConfig.RegisterFlagsWithPrefix(prefix, f)
 }
 
 // Agent is an agent for collecting Prometheus metrics. It acts as a

pkg/metrics/cluster/client/client.go

@@ -40,7 +40,13 @@ func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 
 // RegisterFlags registers flags to the provided flag set.
 func (c *Config) RegisterFlags(f *flag.FlagSet) {
-	c.GRPCClientConfig.RegisterFlagsWithPrefix("prometheus.service-client", f)
+	c.RegisterFlagsWithPrefix("prometheus.", f)
+}
+
+// RegisterFlagsWithPrefix registers flags to the provided flag set with the
+// specified prefix.
+func (c *Config) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
+	c.GRPCClientConfig.RegisterFlagsWithPrefix(prefix+"service-client", f)
 }
 
 // New returns a new scraping service client.