tracing

Documentation

Index

• Constants
• func GetTracingSpanFromContext(ctx context.Context, key string) opentracing.Span
• func SpanError(span opentracing.Span, err error)
• func StartSpanFromContext(ctx context.Context, tracer opentracing.Tracer, operationName string, ...) (opentracing.Span, context.Context)

Constants

const (
	// TagKeyEnvironment is the environment (web, dev, etc.)
	TagKeyEnvironment = "env"
	// TagKeySpanType defines the Span type (web, db, cache).
	TagKeySpanType = "span.type"
	// TagKeyServiceName defines the Service name for this Span.
	TagKeyServiceName = "service.name"
	// TagKeyResourceName defines the Resource name for the Span.
	TagKeyResourceName = "resource.name"
	// TagKeyPID is the pid of the traced process.
	TagKeyPID = "system.pid"
	// TagKeyError is the error tag key. It is usually of type `error`.
	TagKeyError = "error"
	// TagKeyErrorMessage is the error message tag key.
	TagKeyErrorMessage = "error.message"
	// TagKeyErrorStack is the error stack tag key.
	TagKeyErrorStack = "error.stack"

	// TagKeyHTTPMethod is the verb on the request.
	TagKeyHTTPMethod = "http.method"
	// TagKeyHTTPCode is the result status code.
	TagKeyHTTPCode = "http.status_code"
	// TagKeyHTTPURL is the url of the request (typically the raw path).
	TagKeyHTTPURL = "http.url"

	// TagKeyDBApplication is the application that uses a database.
	TagKeyDBApplication = "db.application"
	// TagKeyDBName is the database name.
	TagKeyDBName = "db.name"
	// TagKeyDBUser is the user on the database connection.
	TagKeyDBUser = "db.user"

	// TagKeyJobName is the job name.
	TagKeyJobName = "job.name"
)

These constants are mostly lifted from the datadog/tracing/ext tag values.

const (
	OperationHTTPRouteLookup = "http.route_lookup"
	// OperationHTTPRequest is the http request tracing operation name.
	OperationHTTPRequest = "http.request"
	// OperationHTTPRender is the operation name for rendering a server side view.
	OperationHTTPRender = "http.render"
	// OperationDBPing is the db ping tracing operation.
	OperationSQLPing = "sql.ping"
	// OperationDBPrepare is the db prepare tracing operation.
	OperationSQLPrepare = "sql.prepare"
	// OperationDBQuery is the db query tracing operation.
	OperationSQLQuery = "sql.query"
	// OperationJob is a job operation.
	OperationJob = "job"
)

Operations are actions represented by spans.

const (
	// SpanTypeWeb marks a span as an HTTP server request.
	SpanTypeWeb = "web"
	// SpanTypeHTTP marks a span as an HTTP client request.
	SpanTypeHTTP = "http"
	// SpanTypeSQL marks a span as an SQL operation. These spans may
	// have an "sql.command" tag.
	SpanTypeSQL = "sql"
	// SpanTypeCassandra marks a span as a Cassandra operation. These
	// spans may have an "sql.command" tag.
	SpanTypeCassandra = "cassandra"
	// SpanTypeRedis marks a span as a Redis operation. These spans may
	// also have a "redis.raw_command" tag.
	SpanTypeRedis = "redis"
	// SpanTypeMemcached marks a span as a memcached operation.
	SpanTypeMemcached = "memcached"
	// SpanTypeMongoDB marks a span as a MongoDB operation.
	SpanTypeMongoDB = "mongodb"
	// SpanTypeElasticSearch marks a span as an ElasticSearch operation.
	// These spans may also have an "elasticsearch.body" tag.
	SpanTypeElasticSearch = "elasticsearch"
	// SpanTypeJob is a span type used by cron jobs.
	SpanTypeJob = "job"
)

Span types have similar behaviour to "app types" and help categorize traces in the Datadog application. They can also help fine grain agent level bahviours such as obfuscation and quantization, when these are enabled in the agent's configuration.

const (
	// PriorityUserReject informs the backend that a trace should be rejected and not stored.
	// This should be used by user code overriding default priority.
	PriorityUserReject = -1

	// PriorityAutoReject informs the backend that a trace should be rejected and not stored.
	// This is used by the builtin sampler.
	PriorityAutoReject = 0

	// PriorityAutoKeep informs the backend that a trace should be kept and not stored.
	// This is used by the builtin sampler.
	PriorityAutoKeep = 1

	// PriorityUserKeep informs the backend that a trace should be kept and not stored.
	// This should be used by user code overriding default priority.
	PriorityUserKeep = 2
)

Priority is a hint given to the backend so that it knows which traces to reject or kept. In a distributed context, it should be set before any context propagation (fork, RPC calls) to be effective.

Functions

func GetTracingSpanFromContext

func GetTracingSpanFromContext(ctx context.Context, key string) opentracing.Span

GetTracingSpanFromContext returns a tracing span from a given context.

func SpanError

func SpanError(span opentracing.Span, err error)

SpanError injects error metadata into a span.

func StartSpanFromContext

func StartSpanFromContext(ctx context.Context, tracer opentracing.Tracer, operationName string, opts ...opentracing.StartSpanOption) (opentracing.Span, context.Context)

StartSpanFromContext creates a new span from a given context. It is required because opentracing relies on global state.