* The exp.Stop() as argument to handleErr is getting executed
immediately. Wrap this with an anonymous func so that this
argument is executed when the defer statement is activated.
* From the "Tour of Go" docs on Defer: "The deferred call's arguments
are evaluated immediately, but the function call is not executed
until the surrounding function returns."
* add optional server url arg to http client example
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add Dockerfile to build example http images
Multi-stage Dockerfile with targets for building example http server and
client.
$ docker build --tag the-server --target example-http-server .
$ docker build --tag the-client --target example-http-client .
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add docker-compose.yml file for running examples
This docker compose configuration file will help a new user to compile
and run the example code quickly. Uses the Dockerfile to build images
with compiled examples.
$ docker-compose build http-server http-client
$ docker-compose up http-server http-client
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add newline to last message of example http client
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add optional collector url arg to zipkin client example
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add Dockerfile target to build zipkin client
For building the example zipkin client:
$ docker build --tag zipkin-client --target example-zipkin-client .
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add docker compose service to run zipkin examples
Services to run the zipkin client along with a zipkin collector:
$ docker-compose build zipkin-client
$ docker-compose up zipkin-collector zipkin-client
Since the zipkin collector takes a few seconds before it is ready to
receive traces, I added a simple retry loop to the client command.
The collector service exposes port 9411 so user can visit
http//localhost:9411/ to see the trace sent to the collector. Be sure to
search by the trace id logged by the client.
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* Update Dockerfile with AL2 declaration
As described in https://www.apache.org/licenses/LICENSE-2.0#apply
Co-Authored-By: Tyler Yahn <MrAlias@users.noreply.github.com>
* Update docker-compose.yml with AL2 declaration
As described in https://www.apache.org/licenses/LICENSE-2.0#apply
Co-Authored-By: Tyler Yahn <MrAlias@users.noreply.github.com>
* pass server url as flag in example http client
$ ./client -h
Usage of ./client:
-server string
server url (default "http://localhost:7777/hello")
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* pass zipkin url as flag in example zipkin client
$ ./zipkin -h
Usage of ./zipkin:
-zipkin string
zipkin url (default "http://localhost:9411/api/v2/spans")
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* move Dockerfile and docker-compose.yml into example dir
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add Dockerfile and docker-compose.yml for zipkin example
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* update zipkin example README.md
With instructions on how to use docker-compose to run the example.
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* add http example README.md
With instructions on how to use docker-compose to run the example.
Signed-off-by: Andrew Hsu <xuzuan@gmail.com>
* Update example/http/Dockerfile WORKDIR
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Update example/http/Dockerfile RUN go install
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Update example/http/Dockerfile RUN go install
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Update example/zipkin/Dockerfile WORKDIR
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Update example/zipkin/Dockerfile RUN go install
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Krzesimir Nowak <qdlacz@gmail.com>
Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
* Point to the convenience functions in api/key package
This is to increase the visibility of the api/key package through the
api/core package, otherwise developers often tend to miss the api/key
package altogether and write `core.Key(name).TYPE(value)` and complain
at the verbosity of such a construction. The api/key package would
allow them to write `key.TYPE(name, value)`.
* Use the api/key package where applicable
This transforms all the uses of `core.Key(name).TYPE(value)` to
`key.TYPE(name, value)`. This also should help increasing the
visibility of the api/key package for developers reading the otel-go
code.
Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
* Remove LabelSet frmo api/metric
* SDK tests pass
* Restore benchmarks
* All tests pass
* Remove all mentions of LabelSet
* Test RecordBatch
* Batch test
* Improves benchmark (some)
* Move the benchmark to match HEAD
* Align labels for GOARCH=386
* Add alignment test
* Disable the stress test fo GOARCH=386
* Fix bug
* Move atomic fields into their own file
* Add a TODO
* Comments
* Remove metric.Labels(...)
* FTB
Co-authored-by: Liz Fong-Jones <lizf@honeycomb.io>
Update license header to standard format for source files missed prior.
Add license header to new source files.
Add Makefile check to test all `*.go` and `*.sh` files have a copyright
notice (or comment about them being auto-generated) within the first few
lines.
* Update License header for all source files
- Add Apache 2.0 header to source files that did not have one.
- Update all existing headers dated to 2019 to be 2020
- Remove comma from License header to comply with the Apache 2.0
guidelines.
* Update Copyright notice
Use the standard Copyright notices outlined by the
[CNCF](https://github.com/cncf/foundation/blob/master/copyright-notices.md#copyright-notices)
* Create MeterImpl interface
* Checkpoint w/ sdk.go building
* Checkpoint working on global
* api/global builds (test fails)
* Test fix
* All tests pass
* Comments
* Add two tests
* Comments and uncomment tests
* Precommit part 1
* Still working on tests
* Lint
* Add a test and a TODO
* Cleanup
* Lint
* Interface()->Implementation()
* Apply some feedback
* From feedback
* (A)Synchronous -> (A)Sync
* Add a missing comment
* Apply suggestions from code review
Co-Authored-By: Krzesimir Nowak <qdlacz@gmail.com>
* Rename a variable
Co-authored-by: Krzesimir Nowak <qdlacz@gmail.com>
* Add zipkin exporter
The zipkin exporter implements the SpanBatcher interface. It follows
the current-at-the-time-of-writing document about conversion from
OpenTelemetry span data to Zipkin spans. Which means that endpoint
information is not yet filled.
* Fix typo in docs
* Add a zipkin example
This sends span information to a locally running zipkin collector.
Currently I have a problem getting the collector to show me the spans
after accepting them with HTTP 202. Not sure if this is because of
missing endpoint information.
* Make gitignore consistent
The fixed paths should be prefixed with a slash. The "relative" paths
mean that git will ignore all the files that end with the path.
* Add tests for zipkin exporter
* Update api for Must constructors, with SDK helpers
* Update for Must constructors, leaving TODOs about global errors
* Add tests
* Move Must methods into metric.Must
* Apply the feedback
* Remove interfaces
* Remove more interfaces
* Again...
* Remove a sentence about a dead inteface
* drop gauge instrument
* Restore the benchmark and stress test for lastvalue aggregator, but remove monotonic last-value support
* Rename gauge->lastvalue and remove remaining uses of the word 'gauge'
Co-authored-by: Krzesimir Nowak <krzesimir@kinvolk.io>
The `go.opentelemetry.io/otel/exporter/trace/jaeger` package was
mistakenly released with a `v1.0.0` tag instead of `v0.1.0`. This
resulted in all subsequent releases not becoming the default latest,
meaning that `go get`s pulled in the incompatible `v0.1.0` release of
that package when pulling in more recent packages from other otel
packages. Renaming the `exporter` directory to `exporters` fixes this
issue by consequentially renaming the package.
Additionally, this action also renames *all* exporters. This is
understood to be a disruptive action to existing users as they will need
to update any dependencies they currently have on our exporters.
However, it was decided to take this action regardless. The need to
resolve the existing issue explained above is highly important, and
given the Alpha state of this project these kinds of breaking changes
should be expected (though not without reason).
Resolves#331
Co-authored-by: Rahul Patel <rghetia@yahoo.com>
It would be nice to follow a single schema for naming context
functions. In the trace package we followed the form FooFromContext
and ContextWithFoo. Do the same in the correlation package. The schema
WithFoo is mainly used for functions following the options pattern.
Not sure about a name of the NewContext function, though. For now I
have left it alone.
Co-authored-by: Rahul Patel <rghetia@yahoo.com>
* Move dependencies of tools package to a tools directory
* remove TOOLS_MOD_DIR from ALL_GO_MOD_DIRS in a Makefile.
then run 'go mod tidy' on ALL_GO_MOD_DIRS and TOOLS_MOD_DIR.
Co-authored-by: Rahul Patel <rghetia@yahoo.com>
This PR removes the non-compliant ChildOf and FollowsFrom interfaces
and the Relation type, which were inherited from OpenTracing via the
initial prototype. Instead allow adding a span context to the go
context as a remote span context and use a simple algorithm for
figuring out an actual parent of the new span, which was proposed for
the OpenTelemetry specification.
Also add a way to ignore current span and remote span context in go
context, so we can force the tracer to create a new root span - a span
with a new trace ID.
That required some moderate changes in the opentracing bridge - first
reference with ChildOfRef reference type becomes a local parent, the
rest become links. This also fixes links handling in the meantime. The
downside of the approach proposed here is that we can only set the
remote parent when creating a span through the opentracing API.
Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
* Rename distributedcontext package to correlation
Correlation is the name we agreed upon.
* Move trace propagators to api/trace
The trace propagators tests had to be moved to a testtrace subpackage
to avoid import cycles between api/trace and internal/trace.
Needed to shut up golint about stutter in trace.TraceContext -
TraceContext is a name of a W3C spec, so this stutter is
expected. It's certainly still better than golint's suggestion of
having trace.Context.
* Rename api/propagators to api/propagation
This package will not contain any propagators in the long run, just
the interface definitions.
Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
* Initial skeleton
* Revert noop provider removal
* Checkpoint
* Checkpoint
* Implement Bound instrument and LabelSet
* Add test
* Add a benchmark
* Add a release test
* Document LabelSetDelegator
* Lint and comments
* Add a second Meter test; fix typo; add a panic
* Add a test for the builtin SDK
* Address feedback
* draft using stop aggregating on prometheus client (counters)
* remove prometheus client aggregations
Measures are being exported as summaries since histograms doesn't
exist on OpenTelemetry yet.
Better error handling must be done.
* make pre commit
* add simple error callback
* remove options from collector
* refactor exporter to smaller methods
* wording
* change to snapshot
* lock collection and checkpointset read
* remove histogram options and unexported fields from the Exporter
* documenting why prometheus uses a stateful batcher
* add todo for histograms
* change summaries objects to summary quantiles
* remove histogram buckets from tests
* wording
* rename 'lockedCheckpoint' to 'syncCheckpointSet'
* default summary quantiles should be defaulted to no buckets.
* add quantiles options
* refactor test.CheckpointSet and add docs
* flip aggregators merge
Co-authored-by: Joshua MacDonald <jmacd@users.noreply.github.com>
Change all occurrences of value to pointer receivers
Add meta sys files to .gitignore
Code cleanup e.g.
- Don't capitalize error statements
- Fix ignored errors
- Fix ambiguous variable naming
- Remove unnecessary type casting
- Use named params
Fix#306
* Prom exporter structure
* update prometheus exporter with master and add example.
* remove distributedcontext from prometheus example
* docs and interface checker
* make precommit
* make precommit & remove "OnRegisterError"
* coerce values to float
* return register errors and maybe fix precommit?
* add option to specify a prometheus.Registry
* make exporter implement http.Handler interface
* fix map keys bugs
* remove unused const
* fix modules dependencies.
* add support for histogram
* get metrics with labels values only instead of a labels map
* make exporter implements label encoder interface
* encode labels if the encoder is different.
* split metrics on several files and encapsulate them in structs
* make pre commit
* unexport 'sanitize'
* remove 'AllValues' in favor of 'Points' and change to 'NewDefaultLabelEncoder'
* add prometheus tests
* remove newlines on struct declaration
* formatting
* rewording
* imports
* add todo on labelValues
* blame myself for todo (:
* add todos on sanitize
* add support for summaries. custom remove label encoder.
* imports
* imports
* update with upstream
* Add MetricAggregator.Merge() implementations
* Update from feedback
* Type
* Ckpt
* Ckpt
* Add push controller
* Ckpt
* Add aggregator interfaces, stdout encoder
* Modify basic main.go
* Main is working
* Batch stdout output
* Sum udpate
* Rename stdout
* Add stateless/stateful Batcher options
* Undo a for-loop in the example, remove a done TODO
* Update imports
* Add note
* Rename defaultkeys
* Support variable label encoder to speed OpenMetrics/Statsd export
* Lint
* Checkpoint
* Checkpoint
* Doc
* Precommit/lint
* Simplify Aggregator API
* Record->Identifier
* Remove export.Record a.k.a. Identifier
* Checkpoint
* Propagate errors to the SDK, remove a bunch of 'TODO warn'
* Checkpoint
* Introduce export.Labels
* Comments in export/metric.go
* Comment
* More merge
* More doc
* Complete example
* Lint fixes
* Add a testable example
* Lint
* Dogstats
* Let Export return an error
* Checkpoint
* add a basic stdout exporter test
* Add measure test; fix aggregator APIs
* Use JSON numbers, not strings
* Test stdout exporter error
* Add a test for the call to RangeTest
* Add error handler API to improve correctness test; return errors from RecordOne
* Undo the previous -- do not expose errors
* Add simple selector variations, test
* Repair examples
* Test push controller error handling
* Add SDK label encoder tests
* Add a defaultkeys batcher test
* Add an ungrouped batcher test
* Lint new tests
* Respond to krnowak's feedback
* Checkpoint
* Funciontal example using unixgram
* Tidy the example
* Add a packet-split test
* More tests
* Undo comment
* Use concrete receivers for export records and labels, since the constructors return structs not pointers
* Bug fix for stateful batchers; clone an aggregator for long term storage
* Remove TODO addressed in #318
* Add errors to all aggregator interfaces
* Handle ErrNoLastValue case in stdout exporter
* Move aggregator API into sdk/export/metric/aggregator
* Update all aggregator exported-method comments
* Document the aggregator APIs
* More aggregator comments
* Add multiple updates to the ungrouped test
* Fixes for feedback from Gustavo and Liz
* Producer->CheckpointSet; add FinishedCollection
* Process takes an export.Record
* ReadCheckpoint->CheckpointSet
* EncodeLabels->Encode
* Format a better inconsistent type error; add more aggregator API tests
* More RangeTest test coverage
* Make benbjohnson/clock a test-only dependency
* Handle ErrNoLastValue in stress_test
* Update comments; use a pipe vs a unix socket in the example test
* Update test
* Spelling
* Typo fix
* Rename DefaultLabelEncoder to NewDefaultLabelEncoder for clarity
* Rename DefaultLabelEncoder to NewDefaultLabelEncoder for clarity
* Test different adapters; add ForceEncode to statsd label encoder
* copy of simplelru for attributes without excessive usage of interface{}
This also make sure we only add attributes/links if isRecording.
Move method to export the attributes list to attributeMap.
* run make precommit to update mod files.
* Add MetricAggregator.Merge() implementations
* Update from feedback
* Type
* Ckpt
* Ckpt
* Add push controller
* Ckpt
* Add aggregator interfaces, stdout encoder
* Modify basic main.go
* Main is working
* Batch stdout output
* Sum udpate
* Rename stdout
* Add stateless/stateful Batcher options
* Undo a for-loop in the example, remove a done TODO
* Update imports
* Add note
* Rename defaultkeys
* Support variable label encoder to speed OpenMetrics/Statsd export
* Lint
* Doc
* Precommit/lint
* Simplify Aggregator API
* Record->Identifier
* Remove export.Record a.k.a. Identifier
* Checkpoint
* Propagate errors to the SDK, remove a bunch of 'TODO warn'
* Checkpoint
* Introduce export.Labels
* Comments in export/metric.go
* Comment
* More merge
* More doc
* Complete example
* Lint fixes
* Add a testable example
* Lint
* Let Export return an error
* add a basic stdout exporter test
* Add measure test; fix aggregator APIs
* Use JSON numbers, not strings
* Test stdout exporter error
* Add a test for the call to RangeTest
* Add error handler API to improve correctness test; return errors from RecordOne
* Undo the previous -- do not expose errors
* Add simple selector variations, test
* Repair examples
* Test push controller error handling
* Add SDK label encoder tests
* Add a defaultkeys batcher test
* Add an ungrouped batcher test
* Lint new tests
* Respond to krnowak's feedback
* Undo comment
* Use concrete receivers for export records and labels, since the constructors return structs not pointers
* Bug fix for stateful batchers; clone an aggregator for long term storage
* Remove TODO addressed in #318
* Add errors to all aggregator interfaces
* Handle ErrNoLastValue case in stdout exporter
* Move aggregator API into sdk/export/metric/aggregator
* Update all aggregator exported-method comments
* Document the aggregator APIs
* More aggregator comments
* Add multiple updates to the ungrouped test
* Fixes for feedback from Gustavo and Liz
* Producer->CheckpointSet; add FinishedCollection
* Process takes an export.Record
* ReadCheckpoint->CheckpointSet
* EncodeLabels->Encode
* Format a better inconsistent type error; add more aggregator API tests
* More RangeTest test coverage
* Make benbjohnson/clock a test-only dependency
* Handle ErrNoLastValue in stress_test
* exporter(stackdriver): fix ExportSpans when ctx is not nil
- problem: if ctx is not, calling cancel() will panic
- nil Context already handled in newContextWithTimeout
- add with test
* update go.sum
* mock traceserver for traceclient
* make precommit
* - respect option.Context when get google cred and traceclient
* Revise with timeout, context
- rename blackbox tests package to stackdriver_test
- remove context is nil checking, add to initialization
- add tests for timeout
* fix comments and add jaeger tests
* add more jaeger tests
* remove TODOs and add more jaeger tests
* remove TODOs and add more jaeger tests
* fix jaeger tests
* add jaeger agent tests
* fix merge conflicts and fix test
* fix test name
* automate building all the examples
the EXAMPLES variable was out of date - the stackdriver example wasn't
even built
let's automate it, so we don't need to remember about updating the
variable after adding a new example to the examples directory
* move jaeger example to example directory
this should be in the examples directory, so it can be built by the
make test during CI.
* switch to go 1.13
circle ci uses go 1.12 (which is the oldest 1.12 release) that
contains some bugs with module handling
let's switch to go 1.13.3, the latest go currently
* use a single valid revision of the project in go.mod files
this probably shouldn't be a problem since the switch to go 1.13 in
circle ci, but cleans up the mess and the use of bogus releases
Jaeger exporter was replaced with stdout exporter in the example, so
update the README to reflect that. Also drop the screenshot - it's not
referenced anywhere.
* Update metrics API to match current spec
* update options to match the spec
* drop the global meter API
* more docs
* get rid of leftover mentions about descriptor
* Add Stackdriver Trace exporter for trace.
TODOs for future work is:
* to replace bundler.Bundler
* to add proper tests for the exporter
* to move the exporter to proper repository once it will be created.
* Change to use functions for the exporter initialization instead of
passing option struct directly.
This fix is aliging the same fix for Jaeger (#146, #161)
* Change Option struct to be function type
* Change the original Option struct to be private
* Add line comments to maxMessageEventsPerSpan to leave it for future implementation
* Fix unnessesary expressions specified by `make precommit`
Left errors by `make precommit` in experimental/bridge/opentracing.
* Ran make precommit
* Add new line at EOF
* WIP: Start implementing BatchSpanExporter interfaces
* Change to use RegisterSpanProcessor to register bsp
* Change function names to fit current implementation of sdk
* Removed google.golang.org/api/support/bundler and implement ssp and bsp
* Change spanProcessor as a member of Exporter.
* Fix option names used for BatchSpanProcessor initialization.
* Change Exporter.Shutdown just to unregister spanProcessor.
* Removed copyright statements of OpenCensus.
* Fix small typo and EOF new line
* Fix interfaces of ExportSpan/ExportSpans to meet SpanSyncer/SpanBatcher
* Change to follow context.Context passed in ExportSpan/ExportSpans
* Fix Stackdriver Exporter to hold sync.Once to lock when it is registered and
unregistered.
* initial metrics work
* rename cumulative to counter
* rename bidirectional to nonmonotonic
* rename unidirectional to monotonic
* rename nonnegative to signed
this changes the default semantics a bit - before the change measure
could record negative values by default, now it can't.
The specification draft currently specifies both NonNegative and
Signed, but I think it's a mistake.
* rename instrument to descriptor
* license
* rework measurement values
* make measurement value a tagged union
* simplify to one kind of metrics
* add observers
* change some interfaces to match the spec
* keep integral measurement separate from floating ones
* remove duplicated measurement type
* add checking for options
* reorder some fields and functions
* rename a function
to avoid confusion between the Handle type and the Measure type
* drop disabled field from descriptor
* add back typed API for metrics
* make metric options type safe
* merge alternatives into a single bool
* make value kind name less stuttery
* fix observation callback prototype
* drop context parameter from NewHandle
* drop useless parameter names
* make descriptor an opaque struct
* use a store helper
* handle comment fixes
* reword Alternate comment
* drop the "any value" metrics
* make measurement value simpler
* document value stuff
* add tests for values
* docs
* do not panic if there is no span ID in the event
* rename finish -> end
* missed a few finish -> end spots
* change end back to finish for the bridge span in the openTracing bridge
* fixed grammar, ran make
* Allow specifying custom timestamps for events
Adding event with timestamp is not yet a part of the OpenTelemetry
specification, but this function will come in handy when implementing
the OpenTracing bridge.
* Add opentracing bridge, wrapper tracer and migration interfaces
There are some features missing - setting up links and span kind;
context propagation will only work between two OpenTracing bridges.
* Add some tests for the opentracing bridge
The tests mostly check various aspects of the cooperation between
OpenTracing and OpenTelemetry APIs.
* add propagation api.
* add http propagator interface and w3c propagator implementation.
* remove Extract api from trace.
* remove Extract interface for tracer.
* fix copyright.
* fix variable names and comments.
* move inject/extract out of trace.
* replace INVALID_SPAN_CONTEXT with EmptySpanContext function.
* fix tag.Map.
* make carrier as interface instead of http.Request.
* rename structs and update doc comments..
* add doc.go
* update doc.
* add noop propagator.
* add new propagation api with Supplier interface.
- added Default Tracer which simply propagates SpanContext.
- added CopyOfRemote option to simply create remote span.
* remove old propagator.
* rename propagator to TextFormatPropagator.
* rename default tracer/span as pass_through tracer/span.
* add test for pass through tracer.
* add missing interface to pass through tracer.
* return SpanContext instead of contex.Context from Extract interface.
- also remove PassThroughTracer
* fix review comments.
* add more test cases for traceContext extraction.
* remove tidy temporarily from circle-ci target to avoid build failure.
* allow header ending in dash '-'.
* add inject test for non-zero value other than 01 for traceoption
* add AddLink and Link interface to MockSpan
* fix running go mod tidy on every build.
This is to shrink the PR #100.
The only place where the registry.Variable type was used was metrics,
so just inline that type into its only user. The use of the
registry.Variable type in core.Key was limited to the Name field.
The stats package also used the registry.Variable type, but seems that
also only the Name field was used and the package is going to be
dropped anyway.
* Merge two event methods in span API
There was an agreement to get rid of the Event interface and
consolidate the two methods for adding events into one. See #57.
* Eliminate the use of the Event interface
There is no need for the SDK to provide the implementation of the
Event interface - it is used nowhere.
* Drop the Event interface
It's dead code now.
* Make it possible to override a finish timestamp through options
Opentracing to opentelemetry bridge will certainly use this feature.
* Obey the start time option
* Add tests for events and custom start/end times
* Move scope.Active to trace.CurrentSpan
* Remove scope / does not build
* Global tracer
* Checkpoint
* Checkpoint
* Add key/key.go for key.New
* Comments
* Remove more EventID and ScopeID
* Use Handle to describe static objects
* TODOs
* Remove empty file
* Remove singletons
* Update TODOs
* TODO about map update
* Make stats package option aliases (like key has)
* Rename experimental/streaming
* streaming SDK builds w/ many TODOs
* Get the examples building
* Tidy up metric API / add interface check
* Remove logic from the registry; this is now a placeholder
* fix compile errors.
* fix lint errors.
* add circle-ci job.
* rename IDHigh to TraceIDHigh
* rename the file.
* add go get for goimports and golangci-lint
* enable GO111MODULE and remove comments.
* remove working dir and update cache name
* Add TEST_RESULT env back.
* run go mod tidy.
* remove go mod download.
* add test coverage.
* fix TraceID.
* fix circlefi config error.
* remove install-tools.
* remove ALL_TEST_SRC from Makefile.
This makes it more obvious (without having to look at the code) that
the basic example is actually an example, rather than something tied to
the other examples or some sort of metadata file.
* rename Log and Logf interface to AddEvent and AddEventf.
- also remove log package.
* provide only AddEvent interface to Span
- Event can be created using Event specific interface.
* add var trick for Event interface.
