ddlambda

README

datadog-lambda-go

Datadog Lambda Library for Go enables enhanced Lambda metrics, distributed tracing, and custom metric submission from AWS Lambda functions.

Installation

Follow the installation instructions here.

Enhanced Metrics

Once installed, you should be able to view enhanced metrics for your Lambda function in Datadog.

Check out the official documentation on Datadog Lambda enhanced metrics.

Custom Metrics

Once installed, you should be able to submit custom metrics from your Lambda function.

Check out the instructions for submitting custom metrics from AWS Lambda functions.

Tracing

Set the DD_TRACE_ENABLED environment variable to true to enable Datadog tracing. When Datadog tracing is enabled, the library will inject a span representing the Lambda's execution into the context object. You can then use the included dd-trace-go package to create additional spans from the context or pass the context to other services. For more information, see the dd-trace-go documentation.

import (
  "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
  httptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/net/http"
)

func handleRequest(ctx context.Context, ev events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
  // Trace an HTTP request
  req, _ := http.NewRequestWithContext(ctx, "GET", "https://www.datadoghq.com", nil)
  client := http.Client{}
  client = *httptrace.WrapClient(&client)
  client.Do(req)

  // Create a custom span
  s, _ := tracer.StartSpanFromContext(ctx, "child.span")
  time.Sleep(100 * time.Millisecond)
  s.Finish()
}

You can also use the injected span to connect your logs and traces.

func handleRequest(ctx context.Context, ev events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
  currentSpan, _ := tracer.SpanFromContext(ctx)
  log.Printf("my log message %v", currentSpan)
}

If you are also using AWS X-Ray to trace your Lambda functions, you can set the DD_MERGE_XRAY_TRACES environment variable to true, and Datadog will merge your Datadog and X-Ray traces into a single, unified trace.

Environment Variables

DD_FLUSH_TO_LOG

Set to true (recommended) to send custom metrics asynchronously (with no added latency to your Lambda function executions) through CloudWatch Logs with the help of Datadog Forwarder. Defaults to false. If set to false, you also need to set DD_API_KEY and DD_SITE.

DD_API_KEY

If DD_FLUSH_TO_LOG is set to false (not recommended), the Datadog API Key must be defined.

DD_SITE

If DD_FLUSH_TO_LOG is set to false (not recommended), you must set DD_SITE. Possible values are datadoghq.com, datadoghq.eu, us3.datadoghq.com and ddog-gov.com. The default is datadoghq.com.

DD_LOG_LEVEL

Set to debug enable debug logs from the Datadog Lambda Library. Defaults to info.

DD_ENHANCED_METRICS

Generate enhanced Datadog Lambda integration metrics, such as, aws.lambda.enhanced.invocations and aws.lambda.enhanced.errors. Defaults to true.

DD_TRACE_ENABLED

Initialize the Datadog tracer when set to true. Defaults to false.

DD_MERGE_XRAY_TRACES

If you are using both X-Ray and Datadog tracing, set this to true to merge the X-Ray and Datadog traces. Defaults to false.

Opening Issues

If you encounter a bug with this package, we want to hear about it. Before opening a new issue, search the existing issues to avoid duplicates.

When opening an issue, include the datadog-lambda-go version, go version, and stack trace if available. In addition, include the steps to reproduce when appropriate.

You can also open an issue for a feature request.

Contributing

If you find an issue with this package and have a fix, please feel free to open a pull request following the procedures.

Community

For product feedback and questions, join the #serverless channel in the Datadog community on Slack.

License

Unless explicitly stated otherwise all files in this repository are licensed under the Apache License Version 2.0.

This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2021 Datadog, Inc.

Documentation

Index

• Constants
• func AddTraceHeaders(ctx context.Context, req *http.Request)
• func Distribution(metric string, value float64, tags ...string)
• func GetContext() context.Context
• func GetTraceHeaders(ctx context.Context) map[string]string
• func InvokeDryRun(callback func(ctx context.Context), cfg *Config) (interface{}, error)
• func Metric(metric string, value float64, tags ...string)
• func MetricWithTimestamp(metric string, value float64, timestamp time.Time, tags ...string)
• func WrapHandler(handler interface{}, cfg *Config) interface{}
• type Config

Constants

const (
	// DatadogAPIKeyEnvVar is the environment variable that will be used to set the API key.
	DatadogAPIKeyEnvVar = "DD_API_KEY"
	// DatadogKMSAPIKeyEnvVar is the environment variable that will be sent to KMS for decryption, then used as an API key.
	DatadogKMSAPIKeyEnvVar = "DD_KMS_API_KEY"
	// DatadogSiteEnvVar is the environment variable that will be used as the API host.
	DatadogSiteEnvVar = "DD_SITE"
	// LogLevelEnvVar is the environment variable that will be used to set the log level.
	LogLevelEnvVar = "DD_LOG_LEVEL"
	// ShouldUseLogForwarderEnvVar is the environment variable that enables log forwarding of metrics.
	ShouldUseLogForwarderEnvVar = "DD_FLUSH_TO_LOG"
	// DatadogTraceEnabledEnvVar is the environment variable that enables Datadog tracing.
	DatadogTraceEnabledEnvVar = "DD_TRACE_ENABLED"
	// MergeXrayTracesEnvVar is the environment variable that enables the merging of X-Ray and Datadog traces.
	MergeXrayTracesEnvVar = "DD_MERGE_XRAY_TRACES"

	// DefaultSite to send API messages to.
	DefaultSite = "datadoghq.com"
	// DefaultEnhancedMetrics enables enhanced metrics by default.
	DefaultEnhancedMetrics = true
)

Functions

func AddTraceHeaders

func AddTraceHeaders(ctx context.Context, req *http.Request)

AddTraceHeaders adds Datadog trace headers to a HTTP Request reflecting the current X-Ray subsegment. Deprecated: use native Datadog tracing instead.

func Distribution

func Distribution(metric string, value float64, tags ...string)

Distribution sends a distribution metric to Datadog Deprecated: Use Metric method instead

func GetContext

func GetContext() context.Context

GetContext retrieves the last created lambda context. Only use this if you aren't manually passing context through your call hierarchy.

func GetTraceHeaders

func GetTraceHeaders(ctx context.Context) map[string]string

GetTraceHeaders returns a map containing Datadog trace headers that reflect the current X-Ray subsegment. Deprecated: use native Datadog tracing instead.

func InvokeDryRun

func InvokeDryRun(callback func(ctx context.Context), cfg *Config) (interface{}, error)

InvokeDryRun is a utility to easily run your lambda for testing

func Metric

func Metric(metric string, value float64, tags ...string)

Metric sends a distribution metric to DataDog

func MetricWithTimestamp

func MetricWithTimestamp(metric string, value float64, timestamp time.Time, tags ...string)

MetricWithTimestamp sends a distribution metric to DataDog with a custom timestamp

func WrapHandler

func WrapHandler(handler interface{}, cfg *Config) interface{}

WrapHandler is used to instrument your lambda functions. It returns a modified handler that can be passed directly to the lambda. Start function.

Types

type Config

type Config struct {
	// APIKey is your Datadog API key. This is used for sending metrics.
	APIKey string
	// KMSAPIKey is your Datadog API key, encrypted using the AWS KMS service. This is used for sending metrics.
	KMSAPIKey string
	// ShouldRetryOnFailure is used to turn on retry logic when sending metrics via the API. This can negatively effect the performance of your lambda,
	// and should only be turned on if you can't afford to lose metrics data under poor network conditions.
	ShouldRetryOnFailure bool
	// ShouldUseLogForwarder enabled the log forwarding method for sending metrics to Datadog. This approach requires the user to set up a custom lambda
	// function that forwards metrics from cloudwatch to the Datadog api. This approach doesn't have any impact on the performance of your lambda function.
	ShouldUseLogForwarder bool
	// BatchInterval is the period of time which metrics are grouped together for processing to be sent to the API or written to logs.
	// Any pending metrics are flushed at the end of the lambda.
	BatchInterval time.Duration
	// Site is the host to send metrics to. If empty, this value is read from the 'DD_SITE' environment variable, or if that is empty
	// will default to 'datadoghq.com'.
	Site string
	// DebugLogging will turn on extended debug logging.
	DebugLogging bool
	// EnhancedMetrics enables the reporting of enhanced metrics under `aws.lambda.enhanced*` and adds enhanced metric tags
	EnhancedMetrics bool
	// DDTraceEnabled enables the Datadog tracer.
	DDTraceEnabled bool
	// MergeXrayTraces will cause Datadog traces to be merged with traces from AWS X-Ray.
	MergeXrayTraces bool
	// HttpClientTimeout specifies a time limit for requests to the API. It defaults to 5s.
	HttpClientTimeout time.Duration
	// CircuitBreakerInterval is the cyclic period of the closed state
	// for the CircuitBreaker to clear the internal Counts.
	// default: 30s
	CircuitBreakerInterval time.Duration
	// CircuitBreakerTimeout is the period of the open state,
	// after which the state of the CircuitBreaker becomes half-open.
	// default: 60s
	CircuitBreakerTimeout time.Duration
	// CircuitBreakerTotalFailures after this amount of times
	// of a request failing in the closed state, the state will become open.
	// the counter will get totally reset after CircuitBreakerInterval
	// default: 4
	CircuitBreakerTotalFailures uint32
}

Config gives options for how ddlambda should behave