mirror of
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>
85 lines
2.1 KiB
Go
85 lines
2.1 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 utils
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import (
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"errors"
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"net"
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)
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// This code is borrowed from https://github.com/uber/tchannel-go/blob/dev/localip.go
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// scoreAddr scores how likely the given addr is to be a remote address and returns the
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// IP to use when listening. Any address which receives a negative score should not be used.
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// Scores are calculated as:
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// -1 for any unknown IP addresses.
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// +300 for IPv4 addresses
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// +100 for non-local addresses, extra +100 for "up" interaces.
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func scoreAddr(iface net.Interface, addr net.Addr) (int, net.IP) {
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var ip net.IP
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if netAddr, ok := addr.(*net.IPNet); ok {
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ip = netAddr.IP
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} else if netIP, ok := addr.(*net.IPAddr); ok {
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ip = netIP.IP
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} else {
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return -1, nil
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}
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var score int
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if ip.To4() != nil {
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score += 300
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}
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if iface.Flags&net.FlagLoopback == 0 && !ip.IsLoopback() {
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score += 100
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if iface.Flags&net.FlagUp != 0 {
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score += 100
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}
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}
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return score, ip
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}
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// HostIP tries to find an IP that can be used by other machines to reach this machine.
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func HostIP() (net.IP, error) {
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interfaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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bestScore := -1
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var bestIP net.IP
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// Select the highest scoring IP as the best IP.
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for _, iface := range interfaces {
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addrs, err := iface.Addrs()
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if err != nil {
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// Skip this interface if there is an error.
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continue
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}
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for _, addr := range addrs {
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score, ip := scoreAddr(iface, addr)
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if score > bestScore {
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bestScore = score
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bestIP = ip
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}
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}
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}
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if bestScore == -1 {
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return nil, errors.New("no addresses to listen on")
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}
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return bestIP, nil
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}
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