trace

package
v1.8.1 Latest Latest
Warning

This package is not in the latest version of its module.

Go to latest
Published: Dec 6, 2017 License: MIT Imports: 21 Imported by: 0

README

Trace

Veneur provides an experimental API for tracing requests between hosts. The API is in an experimental state and is subject to change.

The main Veneur tracing API is defined in the trace.go file; however, an OpenTracing compatibility layer is provided for convenience as well. These are functionally equivalent, though it is recommended not to mix the functions. (In other words, if a trace is started using Veneur's tracing API, avoid using the OpenTracing API functions on it or future children).

Eventually, these two interfaces will be consolidated.

Documentation

Overview

Package trace provies an experimental API for initiating traces. Veneur's tracing API also provides an opentracing compatibility layer. The Veneur tracing API is completely independent of the opentracing compatibility layer, with the exception of one convenience function.

Index

Constants

BufferSize is the default size of the SSF buffer. It defaults to enough bytes to accomodate the largest SSF span.

View Source
const DefaultBackoff = 20 * time.Millisecond

DefaultBackoff defaults to 10 milliseconds of initial wait time. Subsequent wait times will add this backoff to the time they wait.

View Source
const DefaultCapacity = 64

DefaultCapacity is the capacity of the span submission queue in a veneur client.

View Source
const DefaultConnectTimeout = 10 * time.Second

DefaultConnectTimeout is to 10 seconts. Any attempt to (re)connect to a veneur will take longer than this. If it would take longer, the span is discarded.

View Source
const DefaultMaxBackoff = 1 * time.Second

DefaultMaxBackoff defaults to 1 second. No reconnection attempt wait interval will be longer than this.

View Source
const DefaultVeneurAddress string = "udp://127.0.0.1:8128"

DefaultVeneurAddress is the address that a reasonable veneur should listen on. Currently it defaults to UDP port 8128.

View Source
const ResourceKey = "resource"

Experimental

Variables

View Source
var ErrClientNotNetworked = fmt.Errorf("client is not using a network backend")

ErrClientNotNetworked indicates that the client being constructed does not support options relevant only to networked clients.

View Source
var ErrNoClient = errors.New("client is not initialized")

ErrNoClient indicates that no client is yet initialized.

View Source
var ErrUnsupportedSpanContext = errors.New("Unsupported SpanContext")
View Source
var ErrWouldBlock = errors.New("sending span would block")

ErrWouldBlock indicates that a client is not able to send a span at the current time.

View Source
var GlobalTracer = Tracer{}

GlobalTracer is the… global tracer!

View Source
var HeaderFormats = []HeaderGroup{

	HeaderGroup{
		TraceID: "x-request-id",
		SpanID:  "x-client-trace-id",
	},

	HeaderGroup{
		TraceID: "Trace-Id",
		SpanID:  "Span-Id",
	},

	HeaderGroup{
		TraceID: "X-Trace-Id",
		SpanID:  "X-Span-Id",
	},

	HeaderGroup{
		TraceID: "Traceid",
		SpanID:  "Spanid",
	},
}

Veneur supports multiple tracing header formats. We try each set of headers until we find one that exists. Note: textMapReaderGet is case insensitive, so the capitalization of these headers is not important.

View Source
var Service = ""

Service is our service name and should be set exactly once, at startup

Functions

func Buffered added in v1.7.0

func Buffered(cl *Client) error

Buffered sets the client to be buffered with the default buffer size (enough to accomodate a single, maximum-sized SSF frame, currently about 16MB).

func Disable added in v1.2.0

func Disable()

(Experimental) Disabled sets tracing to disabled.

func Disabled

func Disabled() bool

func Enable added in v1.2.0

func Enable()

(Experimental) Enabled sets tracing to enabled.

func Flush added in v1.7.0

func Flush(cl *Client) error

Flush instructs a client to flush to the upstream veneur all the spans that were serialized up until the moment that the flush was received. It will wait until the flush is completed (including all reconnection attempts), and return any error caused by flushing the buffer.

Flush returns ErrNoClient if client is nil and ErrWouldBlock if the client is not able to take more requests.

func FlushAsync added in v1.7.0

func FlushAsync(cl *Client, ch chan<- error) error

FlushAsync instructs a buffered client to flush to the upstream veneur all the spans that were serialized up until the moment that the flush was received. Once the client has completed the flush, any error (or nil) is sent down the error channel.

FlushAsync returns ErrNoClient if client is nil and ErrWouldBlock if the client is not able to take more requests.

func Record added in v1.7.0

func Record(cl *Client, span *ssf.SSFSpan, done chan<- error) error

Record instructs the client to serialize and send a span. It does not wait for a delivery attempt, instead the Client will send the result from serializing and submitting the span to the channel done, if it is non-nil.

Record returns ErrNoClient if client is nil and ErrWouldBlock if the client is not able to accomodate another span.

Types

type Client added in v1.7.0

type Client struct {
	// contains filtered or unexported fields
}

Client is a Client that sends traces to Veneur over the network. It represents a pump for span packets from user code to the network (whether it be UDP or streaming sockets, with or without buffers).

Structure

A Client is composed of two parts (each with its own purpose): A serialization part providing backpressure (the front end) and a backend (which is called on a single goroutine).

var DefaultClient *Client

DefaultClient is the client that trace recording happens on by default. If it is nil, no recording happens and ErrNoClient is returned from recording functions.

Note that it is not safe to set this variable concurrently with other goroutines that use the DefaultClient.

func NewBackendClient added in v1.8.0

func NewBackendClient(b ClientBackend, opts ...ClientParam) (*Client, error)

NewBackendClient constructs and returns a Client sending to the ClientBackend passed. Most user code should use NewClient, as NewBackendClient is primarily useful for processing spans internally (e.g. in veneur itself or in test code), without making trips over the network.

func NewClient added in v1.7.0

func NewClient(addrStr string, opts ...ClientParam) (*Client, error)

NewClient constructs a new client that will attempt to connect to addrStr (an address in veneur URL format) using the parameters in opts. It returns the constructed client or an error.

func (*Client) Close added in v1.7.0

func (c *Client) Close() error

Close tears down the entire client. It waits until the backend has closed the network connection (if one was established) and returns any error from closing the connection.

type ClientBackend added in v1.8.0

type ClientBackend interface {
	io.Closer

	// SendSync synchronously sends a span to an upstream
	// veneur.
	//
	// On a networked connection, if it encounters a protocol
	// error in sending, it must loop forever, backing off by
	// n*the backoff interval (until it reaches the maximal
	// backoff interval) and tries to reconnect. If SendSync
	// encounters any non-protocol errors (e.g. in serializing the
	// SSF span), it must return them without reconnecting.
	SendSync(ctx context.Context, span *ssf.SSFSpan) error

	// FlushSync causes all (potentially) buffered data to be sent to
	// the upstream veneur.
	FlushSync(ctx context.Context) error
}

ClientBackend represents the ability of a client to transport SSF spans to a veneur server.

type ClientParam added in v1.7.0

type ClientParam func(*Client) error

ClientParam is an option for NewClient. Its implementation borrows from Dave Cheney's functional options API (https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis).

Unless otherwise noted, ClientParams only apply to networked backends (i.e., those used by NewClient). Using them on non-network-backed clients will return ErrClientNotNetworked on client creation.

func BackoffTime added in v1.7.0

func BackoffTime(t time.Duration) ClientParam

BackoffTime sets the time increment that backoff time is increased (linearly) between every reconnection attempt the backend makes. If this option is not used, the backend uses DefaultBackoff.

func BufferedSize added in v1.7.0

func BufferedSize(size uint) ClientParam

BufferedSize indicates that a client should have a buffer size bytes large.

func Capacity added in v1.7.0

func Capacity(n uint) ClientParam

Capacity indicates how many spans a client's channel should accommodate. This parameter can be used on both generic and networked backends.

func ConnectTimeout added in v1.7.0

func ConnectTimeout(t time.Duration) ClientParam

ConnectTimeout sets the maximum total amount of time a client backend spends trying to establish a connection to a veneur. If a connection can not be established after this timeout has expired (counting from the time the connection is first attempted), the span is discarded. If this option is not used, the backend uses DefaultConnectTimeout.

func MaxBackoffTime added in v1.7.0

func MaxBackoffTime(t time.Duration) ClientParam

MaxBackoffTime sets the maximum time duration waited between reconnection attempts. If this option is not used, the backend uses DefaultMaxBackoff.

type ErrContractViolation

type ErrContractViolation struct {
	// contains filtered or unexported fields
}

func (ErrContractViolation) Error

func (e ErrContractViolation) Error() string

type HeaderGroup added in v1.8.0

type HeaderGroup struct {
	TraceID string
	SpanID  string
}

Lists the names of headers that a specification uses for representing trace information.

type Span

type Span struct {
	*Trace
	// contains filtered or unexported fields
}

Span is a member of a trace

func StartSpanFromContext

func StartSpanFromContext(ctx context.Context, name string, opts ...opentracing.StartSpanOption) (s *Span, c context.Context)

StartSpanFromContext is used to create a child span when the parent trace is in the context

func (*Span) Attach

func (s *Span) Attach(ctx context.Context) context.Context

Attach attaches the span to the context. It delegates to opentracing.ContextWithSpan

func (*Span) BaggageItem

func (s *Span) BaggageItem(restrictedKey string) string

BaggageItem fetches the value of a baggage item in the span.

func (*Span) ClientFinish added in v1.7.0

func (s *Span) ClientFinish(cl *Client)

ClientFinish ends a trace and records it with the given Client.

func (*Span) ClientFinishWithOptions added in v1.7.0

func (s *Span) ClientFinishWithOptions(cl *Client, opts opentracing.FinishOptions)

ClientFinishWithOptions finishes the span and records it on the given client, but with explicit control over timestamps and log data. The BulkLogData field is deprecated and ignored.

func (*Span) Context

func (s *Span) Context() opentracing.SpanContext

func (*Span) Finish

func (s *Span) Finish()

Finish ends a trace end records it with DefaultClient.

func (*Span) FinishWithOptions

func (s *Span) FinishWithOptions(opts opentracing.FinishOptions)

FinishWithOptions finishes the span, but with explicit control over timestamps and log data. The BulkLogData field is deprecated and ignored.

func (*Span) Log

func (s *Span) Log(data opentracing.LogData)

Log is deprecated and unimplemented. It is included only to satisfy the opentracing.Span interface.

func (*Span) LogEvent

func (s *Span) LogEvent(event string)

LogEvent is deprecated and unimplemented. It is included only to satisfy the opentracing.Span interface.

func (*Span) LogEventWithPayload

func (s *Span) LogEventWithPayload(event string, payload interface{})

LogEventWithPayload is deprecated and unimplemented. It is included only to satisfy the opentracing.Span interface.

func (*Span) LogFields

func (s *Span) LogFields(fields ...opentracinglog.Field)

LogFields sets log fields on the underlying span. Currently these are ignored, but they can be fun to set anyway!

func (*Span) LogKV

func (s *Span) LogKV(alternatingKeyValues ...interface{})

func (*Span) SetBaggageItem

func (s *Span) SetBaggageItem(restrictedKey, value string) opentracing.Span

SetBaggageItem sets the value of a baggage in the span.

func (*Span) SetOperationName

func (s *Span) SetOperationName(name string) opentracing.Span

SetOperationName sets the name of the operation being performed in this span.

func (*Span) SetTag

func (s *Span) SetTag(key string, value interface{}) opentracing.Span

SetTag sets the tags on the underlying span

func (*Span) Tracer

func (s *Span) Tracer() opentracing.Tracer

Tracer returns the tracer that created this Span

type Trace

type Trace struct {
	// the ID for the root span
	// which is also the ID for the trace itself
	TraceID int64

	// For the root span, this will be equal
	// to the TraceId
	SpanID int64

	// For the root span, this will be <= 0
	ParentID int64

	// The Resource should be the same for all spans in the same trace
	Resource string

	Start time.Time

	End time.Time

	// If non-zero, the trace will be treated
	// as an error
	Status ssf.SSFSample_Status

	Tags map[string]string

	// Unlike the Resource, this should not contain spaces
	// It should be of the format foo.bar.baz
	Name string

	// Sent holds a channel. If set, this channel receives an
	// error (or nil) when the span has been serialized and sent.
	Sent chan<- error
	// contains filtered or unexported fields
}

Trace is a convenient structural representation of a TraceSpan. It is intended to map transparently to the more general type SSFSample.

func SpanFromContext

func SpanFromContext(c context.Context) *Trace

SpanFromContext is used to create a child span when the parent trace is in the context

func StartChildSpan

func StartChildSpan(parent *Trace) *Trace

StartChildSpan creates a new Span with the specified parent

func StartTrace

func StartTrace(resource string) *Trace

StartTrace is called by to create the root-level span for a trace

func (*Trace) Attach

func (t *Trace) Attach(c context.Context) context.Context

Attach attaches the current trace to the context and returns a copy of the context with that trace stored under the key "trace".

func (*Trace) ClientRecord added in v1.7.0

func (t *Trace) ClientRecord(cl *Client, name string, tags map[string]string) error

ClientRecord uses the given client to send a trace to a veneur instance.

func (*Trace) Duration

func (t *Trace) Duration() time.Duration

Duration is a convenience function for the difference between the Start and End timestamps. It assumes the span has already ended.

func (*Trace) Error

func (t *Trace) Error(err error)

func (*Trace) ProtoMarshalTo

func (t *Trace) ProtoMarshalTo(w io.Writer) error

ProtoMarshalTo writes the Trace as a protocol buffer in text format to the specified writer.

func (*Trace) Record

func (t *Trace) Record(name string, tags map[string]string) error

Record sends a trace to a veneur instance using the DefaultClient .

func (*Trace) SSFSpan added in v1.5.0

func (t *Trace) SSFSpan() *ssf.SSFSpan

SSFSample converts the Trace to an SSFSpan type. It sets the duration, so it assumes the span has already ended. (It is safe to call on a span that has not ended, but the duration field will be invalid)

func (*Trace) SetParent

func (t *Trace) SetParent(parent *Trace)

SetParent updates the ParentId, TraceId, and Resource of a trace based on the parent's values (SpanId, TraceId, Resource).

type Tracer

type Tracer struct {
}

Tracer is a tracer

func (Tracer) Extract

func (t Tracer) Extract(format interface{}, carrier interface{}) (ctx opentracing.SpanContext, err error)

Extract returns a SpanContext given the format and the carrier. The SpanContext returned represents the parent span (ie, SpanId refers to the parent span's own SpanId). TODO support all the BuiltinFormats

func (Tracer) ExtractRequestChild

func (tracer Tracer) ExtractRequestChild(resource string, req *http.Request, name string) (*Span, error)

ExtractRequestChild extracts a span from an HTTP request and creates and returns a new child of that span

func (Tracer) Inject

func (t Tracer) Inject(sm opentracing.SpanContext, format interface{}, carrier interface{}) (err error)

Inject injects the provided SpanContext into the carrier for propagation. It will return opentracing.ErrUnsupportedFormat if the format is not supported. TODO support other SpanContext implementations TODO support all the BuiltinFormats

func (Tracer) InjectRequest

func (tracer Tracer) InjectRequest(t *Trace, req *http.Request) error

InjectRequest injects a trace into an HTTP request header. It is a convenience function for Inject.

func (Tracer) StartSpan

func (t Tracer) StartSpan(operationName string, opts ...opentracing.StartSpanOption) opentracing.Span

StartSpan starts a span with the specified operationName (name) and options. If the options specify a parent span and/or root trace, the name from the root trace will be used. The value returned is always a concrete Span (which satisfies the opentracing.Span interface)

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL