[Tempo] Automatic Logging

pkg/config/config.go

@@ -67,6 +67,12 @@ func (c *Config) ApplyDefaults() error {
 		c.Integrations.PrometheusRemoteWrite = c.Prometheus.Global.RemoteWrite
 	}
 
+	// 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
+	if err := c.Tempo.Validate(c.Loki); err != nil {
+		return err
+	}
+
 	return nil
 }
 

pkg/config/config_test.go

@@ -131,3 +131,50 @@ func TestConfig_Defaults(t *testing.T) {
 	require.Equal(t, prom.DefaultConfig, c.Prometheus)
 	require.Equal(t, integrations.DefaultManagerConfig, c.Integrations)
 }
+
+func TestConfig_TempoLokiValidation(t *testing.T) {
+	// test failure
+	cfg := `
+loki:
+  configs:
+  - name: foo
+    positions:
+      filename: /tmp/positions.yaml
+    clients:
+      - url: http://loki:3100/loki/api/v1/push
+tempo:
+  configs:
+  - name: default
+    automatic_logging:
+      loki_name: default
+      spans: true
+  `
+
+	fs := flag.NewFlagSet("test", flag.ExitOnError)
+	_, err := load(fs, []string{"-config.file", "test"}, func(_ string, _ bool, c *Config) error {
+		return LoadBytes([]byte(cfg), false, c)
+	})
+	require.EqualError(t, err, "error in config file: specified loki config default not found")
+
+	// test success
+	cfg = `
+loki:
+  configs:
+    - name: foo
+      positions:
+        filename: /tmp/positions.yaml
+      clients:
+        - url: http://loki:3100/loki/api/v1/push
+tempo:
+  configs:
+  - name: default
+    automatic_logging:
+      loki_name: foo
+      spans: true`
+
+	fs = flag.NewFlagSet("test", flag.ExitOnError)
+	_, err = load(fs, []string{"-config.file", "test"}, func(_ string, _ bool, c *Config) error {
+		return LoadBytes([]byte(cfg), false, c)
+	})
+	require.NoError(t, err)
+}

pkg/tempo/config.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"time"
 
+	"github.com/grafana/agent/pkg/loki"
 	"github.com/grafana/agent/pkg/tempo/automaticloggingprocessor"
 	"github.com/grafana/agent/pkg/tempo/noopreceiver"
 	"github.com/grafana/agent/pkg/tempo/promsdprocessor"
@@ -61,11 +62,11 @@ func (c *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal((*plain)(c)); err != nil {
 		return err
 	}
-	return c.Validate()
+	return nil
 }
 
 // Validate ensures that the Config is valid.
-func (c *Config) Validate() error {
+func (c *Config) Validate(lokiConfig loki.Config) error {
 	names := make(map[string]struct{}, len(c.Configs))
 	for idx, c := range c.Configs {
 		if c.Name == "" {
@@ -77,6 +78,25 @@ func (c *Config) Validate() error {
 		names[c.Name] = struct{}{}
 	}
 
+	// check to make sure that any referenced Loki configs exist
+	for _, inst := range c.Configs {
+		if inst.AutomaticLogging != nil {
+			found := false
+			lokiName := inst.AutomaticLogging.LokiName
+
+			for _, lokiInst := range lokiConfig.Configs {
+				if lokiInst.Name == lokiName {
+					found = true
+					break
+				}
+			}
+
+			if !found {
+				return fmt.Errorf("specified loki config %s not found", lokiName)
+			}
+		}
+	}
+
 	return nil
 }