ContainerImage.Pinniped/internal/net/phttp/warning.go

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// Copyright 2021 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
package phttp
import (
"net/http"
"os"
"runtime"
"golang.org/x/term"
"k8s.io/apimachinery/pkg/util/net"
"k8s.io/client-go/rest"
"go.pinniped.dev/internal/httputil/roundtripper"
)
func warningWrapper(rt http.RoundTripper, handler rest.WarningHandler) http.RoundTripper {
return roundtripper.WrapFunc(rt, func(req *http.Request) (*http.Response, error) {
resp, err := rt.RoundTrip(req)
handleWarnings(resp, handler)
return resp, err
})
}
func handleWarnings(resp *http.Response, handler rest.WarningHandler) {
if resp == nil {
return
}
warnings, _ := net.ParseWarningHeaders(resp.Header["Warning"]) // safe to ignore errors here
for _, warning := range warnings {
handler.HandleWarningHeader(warning.Code, warning.Agent, warning.Text) // client-go throws away the date
}
}
func getWarningHandler() rest.WarningHandler {
// the client-go rest.WarningHandlers all log warnings with non-empty message and code=299, agent is ignored
// no deduplication or color output when running from a non-terminal such as a pod
if isTerm := term.IsTerminal(int(os.Stderr.Fd())); !isTerm {
return rest.WarningLogger{}
}
// deduplicate and attempt color warnings when running from a terminal
return rest.NewWarningWriter(os.Stderr, rest.WarningWriterOptions{
Deduplicate: true,
Color: allowsColorOutput(),
})
}
// allowsColorOutput returns true if the process environment indicates color output is supported and desired.
// Copied from k8s.io/kubectl/pkg/util/term.AllowsColorOutput.
func allowsColorOutput() bool {
// https://en.wikipedia.org/wiki/Computer_terminal#Dumb_terminals
if os.Getenv("TERM") == "dumb" {
return false
}
// https://no-color.org/
if _, nocolor := os.LookupEnv("NO_COLOR"); nocolor {
return false
}
// On Windows WT_SESSION is set by the modern terminal component.
// Older terminals have poor support for UTF-8, VT escape codes, etc.
if runtime.GOOS == "windows" && os.Getenv("WT_SESSION") == "" {
return false
}
return true
}