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https://github.com/aljazceru/kata-containers.git
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3a1bbd0271
Add initial support for opentracing by using the `jaeger` package.
Since opentracing uses the `context` package, add a `context.Context`
as the first parameter to all the functions that we might want to
trace. Trace "spans" (trace points) are then added by extracting the
trace details from the specified context parameter.
Notes:
- Although the tracer is created in `main()`, the "root span"
(aka the first trace point) is not added until `beforeSubcommands()`.
This is by design and is a compromise: by delaying the creation of the
root span, the spans become much more readable since using the web-based
JaegerUI, you will see traces like this:
```
kata-runtime: kata-runtime create
------------ -------------------
^ ^
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Trace name First span name
(which clearly shows the CLI command that was run)
```
Creating the span earlier means it is necessary to expand 'n' spans in
the UI before you get to see the name of the CLI command that was run.
In adding support, this became very tedious, hence my design decision to
defer the creation of the root span until after signal handling has been
setup and after CLI options have been parsed, but still very early in
the code path.
- At this stage, the tracing stops at the `virtcontainers` call
boundary.
- Tracing is "always on" as there doesn't appear to be a way to toggle
it. However, its resolves to a "nop" unless the tracer can talk to a
jaeger agent.
Note that this commit required a bit of rework to `beforeSubcommands()`
to reduce the cyclomatic complexity.
Fixes #557.
Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
82 lines
2.6 KiB
Go
82 lines
2.6 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package jaeger
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import (
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"time"
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)
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// SamplerOption is a function that sets some option on the sampler
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type SamplerOption func(options *samplerOptions)
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// SamplerOptions is a factory for all available SamplerOption's
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var SamplerOptions samplerOptions
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type samplerOptions struct {
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metrics *Metrics
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maxOperations int
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sampler Sampler
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logger Logger
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samplingServerURL string
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samplingRefreshInterval time.Duration
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}
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// Metrics creates a SamplerOption that initializes Metrics on the sampler,
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// which is used to emit statistics.
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func (samplerOptions) Metrics(m *Metrics) SamplerOption {
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return func(o *samplerOptions) {
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o.metrics = m
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}
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}
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// MaxOperations creates a SamplerOption that sets the maximum number of
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// operations the sampler will keep track of.
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func (samplerOptions) MaxOperations(maxOperations int) SamplerOption {
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return func(o *samplerOptions) {
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o.maxOperations = maxOperations
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}
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}
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// InitialSampler creates a SamplerOption that sets the initial sampler
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// to use before a remote sampler is created and used.
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func (samplerOptions) InitialSampler(sampler Sampler) SamplerOption {
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return func(o *samplerOptions) {
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o.sampler = sampler
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}
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}
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// Logger creates a SamplerOption that sets the logger used by the sampler.
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func (samplerOptions) Logger(logger Logger) SamplerOption {
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return func(o *samplerOptions) {
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o.logger = logger
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}
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}
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// SamplingServerURL creates a SamplerOption that sets the sampling server url
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// of the local agent that contains the sampling strategies.
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func (samplerOptions) SamplingServerURL(samplingServerURL string) SamplerOption {
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return func(o *samplerOptions) {
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o.samplingServerURL = samplingServerURL
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}
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}
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// SamplingRefreshInterval creates a SamplerOption that sets how often the
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// sampler will poll local agent for the appropriate sampling strategy.
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func (samplerOptions) SamplingRefreshInterval(samplingRefreshInterval time.Duration) SamplerOption {
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return func(o *samplerOptions) {
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o.samplingRefreshInterval = samplingRefreshInterval
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}
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}
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