ActiveGo 1.8Package opentracing
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Variables
var (
// ErrUnsupportedFormat occurs when the `format` passed to Tracer.Inject() or
// Tracer.Extract() is not recognized by the Tracer implementation.
ErrUnsupportedFormat = errors.New("opentracing: Unknown or unsupported Inject/Extract format")
// ErrSpanContextNotFound occurs when the `carrier` passed to
// Tracer.Extract() is valid and uncorrupted but has insufficient
// information to extract a SpanContext.
ErrSpanContextNotFound = errors.New("opentracing: SpanContext not found in Extract carrier")
// ErrInvalidSpanContext errors occur when Tracer.Inject() is asked to
// operate on a SpanContext which it is not prepared to handle (for
// example, since it was created by a different tracer implementation).
ErrInvalidSpanContext = errors.New("opentracing: SpanContext type incompatible with tracer")
// ErrInvalidCarrier errors occur when Tracer.Inject() or Tracer.Extract()
// implementations expect a different type of `carrier` than they are
// given.
ErrInvalidCarrier = errors.New("opentracing: Invalid Inject/Extract carrier")
// ErrSpanContextCorrupted occurs when the `carrier` passed to
// Tracer.Extract() is of the expected type but is corrupted.
ErrSpanContextCorrupted = errors.New("opentracing: SpanContext data corrupted in Extract carrier")
)
func ContextWithSpan ¶
func ContextWithSpan(ctx context.Context, span Span) context.Context
ContextWithSpan returns a new `context.Context` that holds a reference to `span`'s SpanContext.
func InitGlobalTracer ¶
func InitGlobalTracer(tracer Tracer)
InitGlobalTracer is deprecated. Please use SetGlobalTracer.
func SetGlobalTracer ¶
func SetGlobalTracer(tracer Tracer)
SetGlobalTracer sets the [singleton] opentracing.Tracer returned by GlobalTracer(). Those who use GlobalTracer (rather than directly manage an opentracing.Tracer instance) should call SetGlobalTracer as early as possible in main(), prior to calling the `StartSpan` global func below. Prior to calling `SetGlobalTracer`, any Spans started via the `StartSpan` (etc) globals are noops.
type BuiltinFormat ¶
BuiltinFormat is used to demarcate the values within package `opentracing` that are intended for use with the Tracer.Inject() and Tracer.Extract() methods.
type BuiltinFormat byte
const (
// Binary represents SpanContexts as opaque binary data.
//
// For Tracer.Inject(): the carrier must be an `io.Writer`.
//
// For Tracer.Extract(): the carrier must be an `io.Reader`.
Binary BuiltinFormat = iota
// TextMap represents SpanContexts as key:value string pairs.
//
// Unlike HTTPHeaders, the TextMap format does not restrict the key or
// value character sets in any way.
//
// For Tracer.Inject(): the carrier must be a `TextMapWriter`.
//
// For Tracer.Extract(): the carrier must be a `TextMapReader`.
TextMap
// HTTPHeaders represents SpanContexts as HTTP header string pairs.
//
// Unlike TextMap, the HTTPHeaders format requires that the keys and values
// be valid as HTTP headers as-is (i.e., character casing may be unstable
// and special characters are disallowed in keys, values should be
// URL-escaped, etc).
//
// For Tracer.Inject(): the carrier must be a `TextMapWriter`.
//
// For Tracer.Extract(): the carrier must be a `TextMapReader`.
//
// See HTTPHeaderCarrier for an implementation of both TextMapWriter
// and TextMapReader that defers to an http.Header instance for storage.
// For example, Inject():
//
// carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
// err := span.Tracer().Inject(
// span, opentracing.HTTPHeaders, carrier)
//
// Or Extract():
//
// carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
// span, err := tracer.Extract(
// opentracing.HTTPHeaders, carrier)
//
HTTPHeaders
)
type FinishOptions ¶
FinishOptions allows Span.FinishWithOptions callers to override the finish timestamp and provide log data via a bulk interface.
type FinishOptions struct {
// FinishTime overrides the Span's finish time, or implicitly becomes
// time.Now() if FinishTime.IsZero().
//
// FinishTime must resolve to a timestamp that's >= the Span's StartTime
// (per StartSpanOptions).
FinishTime time.Time
// LogRecords allows the caller to specify the contents of many LogFields()
// calls with a single slice. May be nil.
//
// None of the LogRecord.Timestamp values may be .IsZero() (i.e., they must
// be set explicitly). Also, they must be >= the Span's start timestamp and
// <= the FinishTime (or time.Now() if FinishTime.IsZero()). Otherwise the
// behavior of FinishWithOptions() is undefined.
//
// If specified, the caller hands off ownership of LogRecords at
// FinishWithOptions() invocation time.
//
// If specified, the (deprecated) BulkLogData must be nil or empty.
LogRecords []LogRecord
// BulkLogData is DEPRECATED.
BulkLogData []LogData
}
type HTTPHeadersCarrier ¶
HTTPHeadersCarrier satisfies both TextMapWriter and TextMapReader.
Example usage for server side:
carrier := opentracing.HttpHeadersCarrier(httpReq.Header) spanContext, err := tracer.Extract(opentracing.HttpHeaders, carrier)
Example usage for client side:
carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
err := tracer.Inject(
span.Context(),
opentracing.HttpHeaders,
carrier)
type HTTPHeadersCarrier http.Header
func (HTTPHeadersCarrier) ForeachKey ¶
func (c HTTPHeadersCarrier) ForeachKey(handler func(key, val string) error) error
ForeachKey conforms to the TextMapReader interface.
func (HTTPHeadersCarrier) Set ¶
func (c HTTPHeadersCarrier) Set(key, val string)
Set conforms to the TextMapWriter interface.
type LogData ¶
LogData is DEPRECATED
type LogData struct {
Timestamp time.Time
Event string
Payload interface{}
}
func (*LogData) ToLogRecord ¶
func (ld *LogData) ToLogRecord() LogRecord
ToLogRecord converts a deprecated LogData to a non-deprecated LogRecord
type LogRecord ¶
LogRecord is data associated with a single Span log. Every LogRecord instance must specify at least one Field.
type LogRecord struct {
Timestamp time.Time
Fields []log.Field
}
type NoopTracer ¶
A NoopTracer is a trivial, minimum overhead implementation of Tracer for which all operations are no-ops.
The primary use of this implementation is in libraries, such as RPC frameworks, that make tracing an optional feature controlled by the end user. A no-op implementation allows said libraries to use it as the default Tracer and to write instrumentation that does not need to keep checking if the tracer instance is nil.
For the same reason, the NoopTracer is the default "global" tracer (see GlobalTracer and SetGlobalTracer functions).
WARNING: NoopTracer does not support baggage propagation.
type NoopTracer struct{}
func (NoopTracer) Extract ¶
func (n NoopTracer) Extract(format interface{}, carrier interface{}) (SpanContext, error)
Extract belongs to the Tracer interface.
func (NoopTracer) Inject ¶
func (n NoopTracer) Inject(sp SpanContext, format interface{}, carrier interface{}) error
Inject belongs to the Tracer interface.
func (NoopTracer) StartSpan ¶
func (n NoopTracer) StartSpan(operationName string, opts ...StartSpanOption) Span
StartSpan belongs to the Tracer interface.
type Span ¶
Span represents an active, un-finished span in the OpenTracing system.
Spans are created by the Tracer interface.
type Span interface {
// Sets the end timestamp and finalizes Span state.
//
// With the exception of calls to Context() (which are always allowed),
// Finish() must be the last call made to any span instance, and to do
// otherwise leads to undefined behavior.
Finish()
// FinishWithOptions is like Finish() but with explicit control over
// timestamps and log data.
FinishWithOptions(opts FinishOptions)
// Context() yields the SpanContext for this Span. Note that the return
// value of Context() is still valid after a call to Span.Finish(), as is
// a call to Span.Context() after a call to Span.Finish().
Context() SpanContext
// Sets or changes the operation name.
SetOperationName(operationName string) Span
// Adds a tag to the span.
//
// If there is a pre-existing tag set for `key`, it is overwritten.
//
// Tag values can be numeric types, strings, or bools. The behavior of
// other tag value types is undefined at the OpenTracing level. If a
// tracing system does not know how to handle a particular value type, it
// may ignore the tag, but shall not panic.
SetTag(key string, value interface{}) Span
// LogFields is an efficient and type-checked way to record key:value
// logging data about a Span, though the programming interface is a little
// more verbose than LogKV(). Here's an example:
//
// span.LogFields(
// log.String("event", "soft error"),
// log.String("type", "cache timeout"),
// log.Int("waited.millis", 1500))
//
// Also see Span.FinishWithOptions() and FinishOptions.BulkLogData.
LogFields(fields ...log.Field)
// LogKV is a concise, readable way to record key:value logging data about
// a Span, though unfortunately this also makes it less efficient and less
// type-safe than LogFields(). Here's an example:
//
// span.LogKV(
// "event", "soft error",
// "type", "cache timeout",
// "waited.millis", 1500)
//
// For LogKV (as opposed to LogFields()), the parameters must appear as
// key-value pairs, like
//
// span.LogKV(key1, val1, key2, val2, key3, val3, ...)
//
// The keys must all be strings. The values may be strings, numeric types,
// bools, Go error instances, or arbitrary structs.
//
// (Note to implementors: consider the log.InterleavedKVToFields() helper)
LogKV(alternatingKeyValues ...interface{})
// SetBaggageItem sets a key:value pair on this Span and its SpanContext
// that also propagates to descendants of this Span.
//
// SetBaggageItem() enables powerful functionality given a full-stack
// opentracing integration (e.g., arbitrary application data from a mobile
// app can make it, transparently, all the way into the depths of a storage
// system), and with it some powerful costs: use this feature with care.
//
// IMPORTANT NOTE #1: SetBaggageItem() will only propagate baggage items to
// *future* causal descendants of the associated Span.
//
// IMPORTANT NOTE #2: Use this thoughtfully and with care. Every key and
// value is copied into every local *and remote* child of the associated
// Span, and that can add up to a lot of network and cpu overhead.
//
// Returns a reference to this Span for chaining.
SetBaggageItem(restrictedKey, value string) Span
// Gets the value for a baggage item given its key. Returns the empty string
// if the value isn't found in this Span.
BaggageItem(restrictedKey string) string
// Provides access to the Tracer that created this Span.
Tracer() Tracer
// Deprecated: use LogFields or LogKV
LogEvent(event string)
// Deprecated: use LogFields or LogKV
LogEventWithPayload(event string, payload interface{})
// Deprecated: use LogFields or LogKV
Log(data LogData)
}
func SpanFromContext ¶
func SpanFromContext(ctx context.Context) Span
SpanFromContext returns the `Span` previously associated with `ctx`, or `nil` if no such `Span` could be found.
NOTE: context.Context != SpanContext: the former is Go's intra-process context propagation mechanism, and the latter houses OpenTracing's per-Span identity and baggage information.
func StartSpan ¶
func StartSpan(operationName string, opts ...StartSpanOption) Span
StartSpan defers to `Tracer.StartSpan`. See `GlobalTracer()`.
func StartSpanFromContext ¶
func StartSpanFromContext(ctx context.Context, operationName string, opts ...StartSpanOption) (Span, context.Context)
StartSpanFromContext starts and returns a Span with `operationName`, using any Span found within `ctx` as a ChildOfRef. If no such parent could be found, StartSpanFromContext creates a root (parentless) Span.
The second return value is a context.Context object built around the returned Span.
Example usage:
SomeFunction(ctx context.Context, ...) {
sp, ctx := opentracing.StartSpanFromContext(ctx, "SomeFunction")
defer sp.Finish()
...
}
type SpanContext ¶
SpanContext represents Span state that must propagate to descendant Spans and across process boundaries (e.g., a <trace_id, span_id, sampled> tuple).
type SpanContext interface {
// ForeachBaggageItem grants access to all baggage items stored in the
// SpanContext.
// The handler function will be called for each baggage key/value pair.
// The ordering of items is not guaranteed.
//
// The bool return value indicates if the handler wants to continue iterating
// through the rest of the baggage items; for example if the handler is trying to
// find some baggage item by pattern matching the name, it can return false
// as soon as the item is found to stop further iterations.
ForeachBaggageItem(handler func(k, v string) bool)
}
type SpanReference ¶
SpanReference is a StartSpanOption that pairs a SpanReferenceType and a referenced SpanContext. See the SpanReferenceType documentation for supported relationships. If SpanReference is created with ReferencedContext==nil, it has no effect. Thus it allows for a more concise syntax for starting spans:
sc, _ := tracer.Extract(someFormat, someCarrier)
span := tracer.StartSpan("operation", opentracing.ChildOf(sc))
The `ChildOf(sc)` option above will not panic if sc == nil, it will just not add the parent span reference to the options.
type SpanReference struct {
Type SpanReferenceType
ReferencedContext SpanContext
}
func ChildOf ¶
func ChildOf(sc SpanContext) SpanReference
ChildOf returns a StartSpanOption pointing to a dependent parent span. If sc == nil, the option has no effect.
See ChildOfRef, SpanReference
func FollowsFrom ¶
func FollowsFrom(sc SpanContext) SpanReference
FollowsFrom returns a StartSpanOption pointing to a parent Span that caused the child Span but does not directly depend on its result in any way. If sc == nil, the option has no effect.
See FollowsFromRef, SpanReference
func (SpanReference) Apply ¶
func (r SpanReference) Apply(o *StartSpanOptions)
Apply satisfies the StartSpanOption interface.
type SpanReferenceType ¶
SpanReferenceType is an enum type describing different categories of relationships between two Spans. If Span-2 refers to Span-1, the SpanReferenceType describes Span-1 from Span-2's perspective. For example, ChildOfRef means that Span-1 created Span-2.
NOTE: Span-1 and Span-2 do *not* necessarily depend on each other for completion; e.g., Span-2 may be part of a background job enqueued by Span-1, or Span-2 may be sitting in a distributed queue behind Span-1.
type SpanReferenceType int
const (
// ChildOfRef refers to a parent Span that caused *and* somehow depends
// upon the new child Span. Often (but not always), the parent Span cannot
// finish until the child Span does.
//
// An timing diagram for a ChildOfRef that's blocked on the new Span:
//
// [-Parent Span---------]
// [-Child Span----]
//
// See http://opentracing.io/spec/
//
// See opentracing.ChildOf()
ChildOfRef SpanReferenceType = iota
// FollowsFromRef refers to a parent Span that does not depend in any way
// on the result of the new child Span. For instance, one might use
// FollowsFromRefs to describe pipeline stages separated by queues,
// or a fire-and-forget cache insert at the tail end of a web request.
//
// A FollowsFromRef Span is part of the same logical trace as the new Span:
// i.e., the new Span is somehow caused by the work of its FollowsFromRef.
//
// All of the following could be valid timing diagrams for children that
// "FollowFrom" a parent.
//
// [-Parent Span-] [-Child Span-]
//
//
// [-Parent Span--]
// [-Child Span-]
//
//
// [-Parent Span-]
// [-Child Span-]
//
// See http://opentracing.io/spec/
//
// See opentracing.FollowsFrom()
FollowsFromRef
)
type StartSpanOption ¶
StartSpanOption instances (zero or more) may be passed to Tracer.StartSpan.
StartSpanOption borrows from the "functional options" pattern, per http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
type StartSpanOption interface {
Apply(*StartSpanOptions)
}
type StartSpanOptions ¶
StartSpanOptions allows Tracer.StartSpan() callers and implementors a mechanism to override the start timestamp, specify Span References, and make a single Tag or multiple Tags available at Span start time.
StartSpan() callers should look at the StartSpanOption interface and implementations available in this package.
Tracer implementations can convert a slice of `StartSpanOption` instances into a `StartSpanOptions` struct like so:
func StartSpan(opName string, opts ...opentracing.StartSpanOption) {
sso := opentracing.StartSpanOptions{}
for _, o := range opts {
o.Apply(&sso)
}
...
}
type StartSpanOptions struct {
// Zero or more causal references to other Spans (via their SpanContext).
// If empty, start a "root" Span (i.e., start a new trace).
References []SpanReference
// StartTime overrides the Span's start time, or implicitly becomes
// time.Now() if StartTime.IsZero().
StartTime time.Time
// Tags may have zero or more entries; the restrictions on map values are
// identical to those for Span.SetTag(). May be nil.
//
// If specified, the caller hands off ownership of Tags at
// StartSpan() invocation time.
Tags map[string]interface{}
}
type StartTime ¶
StartTime is a StartSpanOption that sets an explicit start timestamp for the new Span.
type StartTime time.Time
func (StartTime) Apply ¶
func (t StartTime) Apply(o *StartSpanOptions)
Apply satisfies the StartSpanOption interface.
type Tag ¶
Tag may be passed as a StartSpanOption to add a tag to new spans, or its Set method may be used to apply the tag to an existing Span, for example:
tracer.StartSpan("opName", Tag{"Key", value})
or
Tag{"key", value}.Set(span)
type Tag struct {
Key string
Value interface{}
}
func (Tag) Apply ¶
func (t Tag) Apply(o *StartSpanOptions)
Apply satisfies the StartSpanOption interface.
func (Tag) Set ¶
func (t Tag) Set(s Span)
Set applies the tag to an existing Span.
type Tags ¶
Tags are a generic map from an arbitrary string key to an opaque value type. The underlying tracing system is responsible for interpreting and serializing the values.
type Tags map[string]interface{}
func (Tags) Apply ¶
func (t Tags) Apply(o *StartSpanOptions)
Apply satisfies the StartSpanOption interface.
type TextMapCarrier ¶
TextMapCarrier allows the use of regular map[string]string as both TextMapWriter and TextMapReader.
type TextMapCarrier map[string]string
func (TextMapCarrier) ForeachKey ¶
func (c TextMapCarrier) ForeachKey(handler func(key, val string) error) error
ForeachKey conforms to the TextMapReader interface.
func (TextMapCarrier) Set ¶
func (c TextMapCarrier) Set(key, val string)
Set implements Set() of opentracing.TextMapWriter
type TextMapReader ¶
TextMapReader is the Extract() carrier for the TextMap builtin format. With it, the caller can decode a propagated SpanContext as entries in a map of unicode strings.
type TextMapReader interface {
// ForeachKey returns TextMap contents via repeated calls to the `handler`
// function. If any call to `handler` returns a non-nil error, ForeachKey
// terminates and returns that error.
//
// NOTE: The backing store for the TextMapReader may contain data unrelated
// to SpanContext. As such, Inject() and Extract() implementations that
// call the TextMapWriter and TextMapReader interfaces must agree on a
// prefix or other convention to distinguish their own key:value pairs.
//
// The "foreach" callback pattern reduces unnecessary copying in some cases
// and also allows implementations to hold locks while the map is read.
ForeachKey(handler func(key, val string) error) error
}
type TextMapWriter ¶
TextMapWriter is the Inject() carrier for the TextMap builtin format. With it, the caller can encode a SpanContext for propagation as entries in a map of unicode strings.
type TextMapWriter interface {
// Set a key:value pair to the carrier. Multiple calls to Set() for the
// same key leads to undefined behavior.
//
// NOTE: The backing store for the TextMapWriter may contain data unrelated
// to SpanContext. As such, Inject() and Extract() implementations that
// call the TextMapWriter and TextMapReader interfaces must agree on a
// prefix or other convention to distinguish their own key:value pairs.
Set(key, val string)
}
type Tracer ¶
Tracer is a simple, thin interface for Span creation and SpanContext propagation.
type Tracer interface {
// Create, start, and return a new Span with the given `operationName` and
// incorporate the given StartSpanOption `opts`. (Note that `opts` borrows
// from the "functional options" pattern, per
// http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis)
//
// A Span with no SpanReference options (e.g., opentracing.ChildOf() or
// opentracing.FollowsFrom()) becomes the root of its own trace.
//
// Examples:
//
// var tracer opentracing.Tracer = ...
//
// // The root-span case:
// sp := tracer.StartSpan("GetFeed")
//
// // The vanilla child span case:
// sp := tracer.StartSpan(
// "GetFeed",
// opentracing.ChildOf(parentSpan.Context()))
//
// // All the bells and whistles:
// sp := tracer.StartSpan(
// "GetFeed",
// opentracing.ChildOf(parentSpan.Context()),
// opentracing.Tag("user_agent", loggedReq.UserAgent),
// opentracing.StartTime(loggedReq.Timestamp),
// )
//
StartSpan(operationName string, opts ...StartSpanOption) Span
// Inject() takes the `sm` SpanContext instance and injects it for
// propagation within `carrier`. The actual type of `carrier` depends on
// the value of `format`.
//
// OpenTracing defines a common set of `format` values (see BuiltinFormat),
// and each has an expected carrier type.
//
// Other packages may declare their own `format` values, much like the keys
// used by `context.Context` (see
// https://godoc.org/golang.org/x/net/context#WithValue).
//
// Example usage (sans error handling):
//
// carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
// err := tracer.Inject(
// span.Context(),
// opentracing.HTTPHeaders,
// carrier)
//
// NOTE: All opentracing.Tracer implementations MUST support all
// BuiltinFormats.
//
// Implementations may return opentracing.ErrUnsupportedFormat if `format`
// is not supported by (or not known by) the implementation.
//
// Implementations may return opentracing.ErrInvalidCarrier or any other
// implementation-specific error if the format is supported but injection
// fails anyway.
//
// See Tracer.Extract().
Inject(sm SpanContext, format interface{}, carrier interface{}) error
// Extract() returns a SpanContext instance given `format` and `carrier`.
//
// OpenTracing defines a common set of `format` values (see BuiltinFormat),
// and each has an expected carrier type.
//
// Other packages may declare their own `format` values, much like the keys
// used by `context.Context` (see
// https://godoc.org/golang.org/x/net/context#WithValue).
//
// Example usage (with StartSpan):
//
//
// carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
// clientContext, err := tracer.Extract(opentracing.HTTPHeaders, carrier)
//
// // ... assuming the ultimate goal here is to resume the trace with a
// // server-side Span:
// var serverSpan opentracing.Span
// if err == nil {
// span = tracer.StartSpan(
// rpcMethodName, ext.RPCServerOption(clientContext))
// } else {
// span = tracer.StartSpan(rpcMethodName)
// }
//
//
// NOTE: All opentracing.Tracer implementations MUST support all
// BuiltinFormats.
//
// Return values:
// - A successful Extract returns a SpanContext instance and a nil error
// - If there was simply no SpanContext to extract in `carrier`, Extract()
// returns (nil, opentracing.ErrSpanContextNotFound)
// - If `format` is unsupported or unrecognized, Extract() returns (nil,
// opentracing.ErrUnsupportedFormat)
// - If there are more fundamental problems with the `carrier` object,
// Extract() may return opentracing.ErrInvalidCarrier,
// opentracing.ErrSpanContextCorrupted, or implementation-specific
// errors.
//
// See Tracer.Inject().
Extract(format interface{}, carrier interface{}) (SpanContext, error)
}
func GlobalTracer ¶
func GlobalTracer() Tracer
GlobalTracer returns the global singleton `Tracer` implementation. Before `SetGlobalTracer()` is called, the `GlobalTracer()` is a noop implementation that drops all data handed to it.
Subdirectories
| Name | Synopsis |
|---|---|
| .. | |
| ext | |
| log | |
| mocktracer | |