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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>
100 lines
2.8 KiB
Go
100 lines
2.8 KiB
Go
// Copyright (c) 2018 The Jaeger Authors.
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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 remote
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import (
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"time"
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"github.com/uber/jaeger-client-go"
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)
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const (
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defaultHostPort = "localhost:5778"
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defaultRefreshInterval = time.Second * 5
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)
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// Option is a function that sets some option on the Throttler
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type Option func(options *options)
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// Options is a factory for all available options
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var Options options
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type options struct {
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metrics *jaeger.Metrics
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logger jaeger.Logger
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hostPort string
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refreshInterval time.Duration
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synchronousInitialization bool
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}
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// Metrics creates an Option that initializes Metrics on the Throttler, which is used to emit statistics.
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func (options) Metrics(m *jaeger.Metrics) Option {
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return func(o *options) {
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o.metrics = m
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}
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}
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// Logger creates an Option that sets the logger used by the Throttler.
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func (options) Logger(logger jaeger.Logger) Option {
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return func(o *options) {
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o.logger = logger
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}
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}
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// HostPort creates an Option that sets the hostPort of the local agent that keeps track of credits.
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func (options) HostPort(hostPort string) Option {
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return func(o *options) {
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o.hostPort = hostPort
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}
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}
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// RefreshInterval creates an Option that sets how often the Throttler will poll local agent for
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// credits.
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func (options) RefreshInterval(refreshInterval time.Duration) Option {
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return func(o *options) {
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o.refreshInterval = refreshInterval
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}
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}
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// SynchronousInitialization creates an Option that determines whether the throttler should synchronously
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// fetch credits from the agent when an operation is seen for the first time. This should be set to true
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// if the client will be used by a short lived service that needs to ensure that credits are fetched upfront
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// such that sampling or throttling occurs.
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func (options) SynchronousInitialization(b bool) Option {
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return func(o *options) {
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o.synchronousInitialization = b
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}
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}
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func applyOptions(o ...Option) options {
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opts := options{}
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for _, option := range o {
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option(&opts)
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}
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if opts.metrics == nil {
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opts.metrics = jaeger.NewNullMetrics()
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}
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if opts.logger == nil {
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opts.logger = jaeger.NullLogger
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}
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if opts.hostPort == "" {
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opts.hostPort = defaultHostPort
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}
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if opts.refreshInterval == 0 {
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opts.refreshInterval = defaultRefreshInterval
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}
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return opts
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}
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