Allow setting different log levels for log tags

jobs/bosh-dns-windows/spec

@@ -167,7 +167,10 @@ properties:
   logging.format.timestamp:
     description: "Format for the timestamp in the component logs.  Valid values are 'rfc3339' and 'deprecated'."
     default: "rfc3339"
-
+
+  logging.tags:
+      description: "Provide logging configuration for log tags to overwrite the default logger behavior (e.g log_level property)"
+
   post_start.timeout:
     description: "Number of seconds to attempt to retry Resolve-DnsName before timing out the post-start script"
     default: 60

jobs/bosh-dns/spec

@@ -174,3 +174,6 @@ properties:
   logging.format.timestamp:
     description: "Format for the timestamp in the component logs.  Valid values are 'rfc3339' and 'deprecated'."
     default: "rfc3339"
+
+  logging.tags:
+      description: "Provide logging configuration for log tags to overwrite the default logger behavior (e.g log_level property)"

jobs/bosh-dns/templates/config.json.erb

@@ -46,7 +46,8 @@
   logging: {
     format: {
       timestamp: p('logging.format.timestamp')
-    }
+    },
+    tags: p('logging.tags')
   }
 }.to_json
 %>

src/bosh-dns/dns/config/config.go

@@ -54,6 +54,22 @@ func (c Config) GetLogLevel() (boshlog.LogLevel, error) {
 	return level, nil
 }
 
+func (c Config) GetLoggingTags() []boshlog.LogTag {
+	var tags []boshlog.LogTag
+
+	for _, logTag := range c.Logging.Tags {
+		loggerLevelValue, err := boshlog.Levelify(logTag.LogLevel)
+		if err != nil {
+			continue
+		}
+		tags = append(tags, boshlog.LogTag{
+			Name:     logTag.Name,
+			LogLevel: loggerLevelValue,
+		})
+	}
+	return tags
+}
+
 func (c Config) UseRFC3339Formatting() bool {
 	return strings.EqualFold(c.Logging.Format.TimeStamp, RFCFormatting)
 }
@@ -91,8 +107,14 @@ type InternalUpcheckDomain struct {
 	DNSQuery string `json:"dns_query"`
 }
 
+type LogTag struct {
+	Name     string `json:"name"`
+	LogLevel string `json:"log_level"`
+}
+
 type LoggingConfig struct {
 	Format FormatConfig `json:"format,omitempty"`
+	Tags   []LogTag     `json:"tags,omitempty"`
 }
 
 type FormatConfig struct {

src/bosh-dns/dns/config/config_test.go

@@ -390,6 +390,20 @@ var _ = Describe("Config", func() {
 		})
 	})
 
+	Context("LoggingTags", func() {
+		It("returns levelified logging tags", func() {
+			configFilePath := writeConfigFile(`{"address": "127.0.0.1", "port": 53, "logging":{"tags": [
+				{"name": "ForwardHandler", "log_level": "DEBUG"}, {"name": "TEST", "log_level": "INVALID"},
+				{"name": "main", "log_level": "ERROR"}]}}`)
+
+			dnsConfig, err := config.LoadFromFile(configFilePath)
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(dnsConfig.GetLoggingTags()).To(Equal(
+				[]boshlog.LogTag{{"ForwardHandler", 0}, {"main", 3}}))
+		})
+	})
+
 	Context("AppendDefaultDNSPortIfMissing", func() {
 		It("allows multiple recursors to be configured with default port of 53", func() {
 			recursors, err := config.AppendDefaultDNSPortIfMissing([]string{"8.8.8.8", "10.244.4.4:9700", "2001:db8::1", "[2001:db8::1]:1234"})

src/bosh-dns/dns/main.go

@@ -78,6 +78,7 @@ func mainExitCode() int {
 	if config.UseRFC3339Formatting() {
 		logger.UseRFC3339Timestamps()
 	}
+	logger.UseTags(config.GetLoggingTags())
 	logTag := "main"
 	logger.Info(logTag, "bosh-dns starting")
 	defer logger.FlushTimeout(5 * time.Second) //nolint:errcheck