Custom otel support

README.md

@@ -48,17 +48,19 @@ The core module is the base module for cold brew and provides the base implement
 - [func SetupLogger\(logLevel string, jsonlogs bool\) error](<#SetupLogger>)
 - [func SetupNROpenTelemetry\(serviceName, license, version string, ratio float64\) error](<#SetupNROpenTelemetry>)
 - [func SetupNewRelic\(serviceName, apiKey string, tracing bool\) error](<#SetupNewRelic>)
+- [func SetupOpenTelemetry\(config OTLPConfig\) error](<#SetupOpenTelemetry>)
 - [func SetupReleaseName\(rel string\)](<#SetupReleaseName>)
 - [func SetupSentry\(dsn string\)](<#SetupSentry>)
 - [type CB](<#CB>)
   - [func New\(c config.Config\) CB](<#New>)
 - [type CBGracefulStopper](<#CBGracefulStopper>)
 - [type CBService](<#CBService>)
 - [type CBStopper](<#CBStopper>)
+- [type OTLPConfig](<#OTLPConfig>)
 
 
 <a name="ConfigureInterceptors"></a>
-## func [ConfigureInterceptors](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L204>)
+## func [ConfigureInterceptors](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L306>)
 
 ```go
 func ConfigureInterceptors(DoNotLogGRPCReflection bool, traceHeaderName string)
@@ -67,7 +69,7 @@ func ConfigureInterceptors(DoNotLogGRPCReflection bool, traceHeaderName string)
 ConfigureInterceptors configures the interceptors package with the provided DoNotLogGRPCReflection is a boolean that indicates whether to log the grpc.reflection.v1alpha.ServerReflection service calls in logs traceHeaderName is the name of the header to use for tracing \(e.g. X\-Trace\-Id\) \- if empty, defaults to X\-Trace\-Id
 
 <a name="InitializeVTProto"></a>
-## func [InitializeVTProto](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L249>)
+## func [InitializeVTProto](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L351>)
 
 ```go
 func InitializeVTProto()
@@ -78,7 +80,7 @@ InitializeVTProto initializes the vtproto package for use with the service
 https://github.com/planetscale/vtprotobuf?tab=readme-ov-file#mixing-protobuf-implementations-with-grpc
 
 <a name="SetupAutoMaxProcs"></a>
-## func [SetupAutoMaxProcs](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L215>)
+## func [SetupAutoMaxProcs](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L317>)
 
 ```go
 func SetupAutoMaxProcs()
@@ -96,7 +98,7 @@ func SetupEnvironment(env string)
 SetupEnvironment sets the environment This is used to identify the environment in Sentry and New Relic env is the environment to set for the service \(e.g. prod, staging, dev\)
 
 <a name="SetupHystrixPrometheus"></a>
-## func [SetupHystrixPrometheus](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L196>)
+## func [SetupHystrixPrometheus](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L298>)
 
 ```go
 func SetupHystrixPrometheus()
@@ -114,13 +116,22 @@ func SetupLogger(logLevel string, jsonlogs bool) error
 SetupLogger sets up the logger It uses the coldbrew logger to log messages to stdout logLevel is the log level to set for the logger jsonlogs is a boolean to enable or disable json logs
 
 <a name="SetupNROpenTelemetry"></a>
-## func [SetupNROpenTelemetry](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L140>)
+## func [SetupNROpenTelemetry](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L282>)
 
 ```go
 func SetupNROpenTelemetry(serviceName, license, version string, ratio float64) error
 ```
 
-setupOpenTelemetry sets up the OpenTelemetry tracing It uses the New Relic OTLP exporter to send traces to New Relic One APM and Insights serviceName is the name of the service license is the New Relic license key version is the version of the service ratio is the sampling ratio to use for traces
+SetupNROpenTelemetry sets up OpenTelemetry tracing with New Relic
+
+This function configures OpenTelemetry to send traces to New Relic's OTLP endpoint. It's a convenience wrapper around SetupOpenTelemetry with New Relic\-specific configuration.
+
+Parameters:
+
+- serviceName: the name of the service
+- license: the New Relic license key
+- version: the version of the service
+- ratio: the sampling ratio to use for traces \(0.0 to 1.0\)
 
 <a name="SetupNewRelic"></a>
 ## func [SetupNewRelic](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L45>)
@@ -131,6 +142,44 @@ func SetupNewRelic(serviceName, apiKey string, tracing bool) error
 
 SetupNewRelic sets up the New Relic tracing and monitoring agent for the service It uses the New Relic Go Agent to send traces to New Relic One APM and Insights serviceName is the name of the service apiKey is the New Relic license key tracing is a boolean to enable or disable tracing
 
+<a name="SetupOpenTelemetry"></a>
+## func [SetupOpenTelemetry](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L200>)
+
+```go
+func SetupOpenTelemetry(config OTLPConfig) error
+```
+
+SetupOpenTelemetry sets up OpenTelemetry tracing with a generic OTLP exporter
+
+This function provides a flexible way to configure OpenTelemetry tracing with any OTLP\-compatible backend. It sets up the trace provider, configures sampling, and optionally sets up an OpenTracing bridge for compatibility.
+
+Example usage with Jaeger:
+
+```
+config := OTLPConfig{
+    Endpoint:             "localhost:4317",
+    ServiceName:          "my-service",
+    ServiceVersion:       "v1.0.0",
+    SamplingRatio:        0.1,
+    UseOpenTracingBridge: true,
+    Insecure:            true,  // for local development
+}
+err := SetupOpenTelemetry(config)
+```
+
+Example usage with Honeycomb:
+
+```
+config := OTLPConfig{
+    Endpoint:       "api.honeycomb.io:443",
+    Headers:        map[string]string{"x-honeycomb-team": "your-api-key"},
+    ServiceName:    "my-service",
+    ServiceVersion: "v1.0.0",
+    SamplingRatio:  0.2,
+}
+err := SetupOpenTelemetry(config)
+```
+
 <a name="SetupReleaseName"></a>
 ## func [SetupReleaseName](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L103>)
 
@@ -171,7 +220,7 @@ type CB interface {
 ```
 
 <a name="New"></a>
-### func [New](<https://github.com/go-coldbrew/core/blob/main/core.go#L444>)
+### func [New](<https://github.com/go-coldbrew/core/blob/main/core.go#L502>)
 
 ```go
 func New(c config.Config) CB
@@ -223,4 +272,47 @@ type CBStopper interface {
 }
 ```
 
+<a name="OTLPConfig"></a>
+## type [OTLPConfig](<https://github.com/go-coldbrew/core/blob/main/initializers.go#L138-L170>)
+
+OTLPConfig holds configuration for OpenTelemetry OTLP exporter
+
+This struct provides a flexible way to configure OpenTelemetry tracing with any OTLP\-compatible backend \(e.g., Jaeger, Honeycomb, New Relic, etc.\)
+
+```go
+type OTLPConfig struct {
+    // Endpoint is the OTLP gRPC endpoint to send traces to
+    // Examples: "localhost:4317", "otlp.nr-data.net:4317", "api.honeycomb.io:443"
+    Endpoint string
+
+    // Headers are custom headers to send with each request
+    // Examples:
+    //   New Relic: {"api-key": "your-license-key"}
+    //   Honeycomb: {"x-honeycomb-team": "your-api-key"}
+    Headers map[string]string
+
+    // ServiceName is the name of the service sending traces
+    ServiceName string
+
+    // ServiceVersion is the version of the service
+    ServiceVersion string
+
+    // SamplingRatio is the ratio of traces to sample (0.0 to 1.0)
+    // 1.0 means sample all traces, 0.1 means sample 10% of traces
+    SamplingRatio float64
+
+    // Compression specifies the compression type (e.g., "gzip", "none")
+    // If empty, defaults to "gzip"
+    Compression string
+
+    // UseOpenTracingBridge determines whether to set up OpenTracing compatibility bridge
+    // This allows using OpenTracing instrumentation with OpenTelemetry
+    UseOpenTracingBridge bool
+
+    // Insecure disables TLS verification for the connection
+    // Only use this for local development or testing
+    Insecure bool
+}
+```
+
 Generated by [gomarkdoc](<https://github.com/princjef/gomarkdoc>)

config/README.md

@@ -16,7 +16,7 @@ import "github.com/go-coldbrew/core/config"
 
 
 <a name="Config"></a>
-## type [Config](<https://github.com/go-coldbrew/core/blob/main/config/config.go#L6-L101>)
+## type [Config](<https://github.com/go-coldbrew/core/blob/main/config/config.go#L6-L129>)
 
 Config is the configuration for the Coldbrew server It is populated from environment variables and has sensible defaults for all fields so that you can just use it as is without any configuration The following environment variables are supported and can be used to override the defaults for the fields
 
@@ -116,6 +116,31 @@ type Config struct {
     // DisableVTProtobuf disables the use of the vtprotobuf marshaller and unmarshaller for GRPC
     // https://github.com/planetscale/vtprotobuf
     DisableVTProtobuf bool `envconfig:"DISABLE_VT_PROTOBUF" default:"false"`
+    // GRPCMaxSendMsgSize and GRPCMaxRecvMsgSize are the maximum message
+    // sizes for sending and receiving messages over GRPC
+    GRPCMaxSendMsgSize int `envconfig:"GRPC_MAX_SEND_MSG_SIZE" default:"2147483647"` // Unlimited
+    GRPCMaxRecvMsgSize int `envconfig:"GRPC_MAX_RECV_MSG_SIZE" default:"4194304"`    // 4MB
+
+    // OTLPEndpoint is the OTLP gRPC endpoint to send traces to
+    // Examples: "localhost:4317", "api.honeycomb.io:443", "otel-collector:4317"
+    // When set, this takes precedence over NewRelic OpenTelemetry configuration
+    OTLPEndpoint string `envconfig:"OTLP_ENDPOINT" default:""`
+    // OTLPHeaders are custom headers to send with each OTLP request
+    // Format: "key1=value1,key2=value2" (comma-separated key=value pairs)
+    // Example: "x-honeycomb-team=your-api-key" or "api-key=your-key,dataset=your-dataset"
+    OTLPHeaders string `envconfig:"OTLP_HEADERS" default:""`
+    // OTLPCompression specifies the compression type for OTLP requests
+    // Options: "gzip", "none". Defaults to "gzip" if not specified
+    OTLPCompression string `envconfig:"OTLP_COMPRESSION" default:"gzip"`
+    // OTLPInsecure disables TLS verification for OTLP connection
+    // Only use this for local development or testing with self-signed certificates
+    OTLPInsecure bool `envconfig:"OTLP_INSECURE" default:"false"`
+    // OTLPSamplingRatio is the ratio of traces to sample (0.0 to 1.0)
+    // 1.0 means sample all traces, 0.1 means sample 10% of traces
+    OTLPSamplingRatio float64 `envconfig:"OTLP_SAMPLING_RATIO" default:"0.2"`
+    // OTLPUseOpenTracingBridge determines whether to set up OpenTracing compatibility bridge
+    // This allows using existing OpenTracing instrumentation with OpenTelemetry
+    OTLPUseOpenTracingBridge bool `envconfig:"OTLP_USE_OPENTRACING_BRIDGE" default:"true"`
 }
 ```
 

config/config.go

@@ -102,4 +102,28 @@ type Config struct {
 	// sizes for sending and receiving messages over GRPC
 	GRPCMaxSendMsgSize int `envconfig:"GRPC_MAX_SEND_MSG_SIZE" default:"2147483647"` // Unlimited
 	GRPCMaxRecvMsgSize int `envconfig:"GRPC_MAX_RECV_MSG_SIZE" default:"4194304"`    // 4MB
+
+	// Custom OpenTelemetry OTLP Configuration
+	// When OTLPEndpoint is set, it takes precedence over NewRelic OpenTelemetry configuration
+
+	// OTLPEndpoint is the OTLP gRPC endpoint to send traces to
+	// Examples: "localhost:4317", "api.honeycomb.io:443", "otel-collector:4317"
+	// When set, this takes precedence over NewRelic OpenTelemetry configuration
+	OTLPEndpoint string `envconfig:"OTLP_ENDPOINT" default:""`
+	// OTLPHeaders are custom headers to send with each OTLP request
+	// Format: "key1=value1,key2=value2" (comma-separated key=value pairs)
+	// Example: "x-honeycomb-team=your-api-key" or "api-key=your-key,dataset=your-dataset"
+	OTLPHeaders string `envconfig:"OTLP_HEADERS" default:""`
+	// OTLPCompression specifies the compression type for OTLP requests
+	// Options: "gzip", "none". Defaults to "gzip" if not specified
+	OTLPCompression string `envconfig:"OTLP_COMPRESSION" default:"gzip"`
+	// OTLPInsecure disables TLS verification for OTLP connection
+	// Only use this for local development or testing with self-signed certificates
+	OTLPInsecure bool `envconfig:"OTLP_INSECURE" default:"false"`
+	// OTLPSamplingRatio is the ratio of traces to sample (0.0 to 1.0)
+	// 1.0 means sample all traces, 0.1 means sample 10% of traces
+	OTLPSamplingRatio float64 `envconfig:"OTLP_SAMPLING_RATIO" default:"0.2"`
+	// OTLPUseOpenTracingBridge determines whether to set up OpenTracing compatibility bridge
+	// This allows using existing OpenTracing instrumentation with OpenTelemetry
+	OTLPUseOpenTracingBridge bool `envconfig:"OTLP_USE_OPENTRACING_BRIDGE" default:"true"`
 }

core.go

@@ -60,6 +60,26 @@ func (c *cb) SetOpenAPIHandler(handler http.Handler) {
 	c.openAPIHandler = handler
 }
 
+// parseHeaders parses a comma-separated string of key=value pairs into a map
+// Example: "key1=value1,key2=value2" -> map[string]string{"key1": "value1", "key2": "value2"}
+func parseHeaders(headerString string) map[string]string {
+	headers := make(map[string]string)
+	if headerString == "" {
+		return headers
+	}
+
+	pairs := strings.SplitSeq(headerString, ",")
+	for pair := range pairs {
+		kv := strings.SplitN(strings.TrimSpace(pair), "=", 2)
+		if len(kv) == 2 {
+			headers[strings.TrimSpace(kv[0])] = strings.TrimSpace(kv[1])
+		} else {
+			log.Warn(context.Background(), "msg", "Ignoring malformed header pair Expected format 'key=value'", "pair", pair)
+		}
+	}
+	return headers
+}
+
 // processConfig processes the config and sets up the logger, newrelic, sentry, environment, release name, jaeger, hystrix prometheus and signal handler
 func (c *cb) processConfig() {
 	SetupLogger(c.config.LogLevel, c.config.JSONLogs)
@@ -94,13 +114,35 @@ func (c *cb) processConfig() {
 	if c.config.EnablePrometheusGRPCHistogram {
 		grpc_prometheus.EnableHandlingTimeHistogram()
 	}
-	if c.config.NewRelicOpentelemetry {
-		SetupNROpenTelemetry(
+
+	// Setup OpenTelemetry - custom OTLP takes precedence over New Relic
+	if c.config.OTLPEndpoint != "" {
+		// Use custom OTLP configuration
+		headers := parseHeaders(c.config.OTLPHeaders)
+		otlpConfig := OTLPConfig{
+			Endpoint:             c.config.OTLPEndpoint,
+			Headers:              headers,
+			ServiceName:          c.config.AppName,
+			ServiceVersion:       c.config.ReleaseName,
+			SamplingRatio:        c.config.OTLPSamplingRatio,
+			Compression:          c.config.OTLPCompression,
+			UseOpenTracingBridge: c.config.OTLPUseOpenTracingBridge,
+			Insecure:             c.config.OTLPInsecure,
+		}
+		if err := SetupOpenTelemetry(otlpConfig); err != nil {
+			log.Error(context.Background(), "msg", "Failed to setup custom OTLP", "err", err)
+		}
+	} else if c.config.NewRelicOpentelemetry {
+		// Fall back to New Relic OpenTelemetry if no custom OTLP is configured
+		 err := SetupNROpenTelemetry(
 			nrName,
 			c.config.NewRelicLicenseKey,
 			c.config.ReleaseName,
 			c.config.NewRelicOpentelemetrySample,
 		)
+		if err != nil {
+			log.Error(context.Background(), "msg", "Failed to setup New Relic OpenTelemetry", "err", err)
+		}
 	}
 }
 
@@ -395,7 +437,10 @@ func (c *cb) close() {
 	for _, closer := range c.closers {
 		if closer != nil {
 			log.Info(context.Background(), "closing", closer)
-			closer.Close()
+			err := closer.Close()
+			if err != nil {
+				log.Error(context.Background(), "msg", "Failed to close resource", "err", err, "resource", closer)
+			}
 		}
 	}
 }
@@ -426,7 +471,12 @@ func (c *cb) Stop(dur time.Duration) error {
 	}
 	log.Info(context.Background(), "msg", "Server shut down started, bye bye")
 	if c.httpServer != nil {
-		go c.httpServer.Shutdown(ctx)
+		go func(ctx context.Context, c *cb) {
+			err := c.httpServer.Shutdown(ctx)
+			if err != nil {
+				log.Error(context.Background(), "msg", "http server shutdown error", "err", err)
+			}
+		}(ctx, c) // shutdown http server gracefully
 	}
 	if c.grpcServer != nil {
 		timedCall(ctx, c.grpcServer.GracefulStop)