mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-20 23:46:23 +01:00
199 lines
6.8 KiB
Go
199 lines
6.8 KiB
Go
// Copyright 2015 The Prometheus Authors
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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 expfmt
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import (
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"fmt"
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"io"
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"net/http"
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"google.golang.org/protobuf/encoding/protodelim"
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"google.golang.org/protobuf/encoding/prototext"
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"github.com/prometheus/common/model"
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"github.com/munnerz/goautoneg"
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dto "github.com/prometheus/client_model/go"
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)
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// Encoder types encode metric families into an underlying wire protocol.
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type Encoder interface {
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Encode(*dto.MetricFamily) error
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}
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// Closer is implemented by Encoders that need to be closed to finalize
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// encoding. (For example, OpenMetrics needs a final `# EOF` line.)
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//
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// Note that all Encoder implementations returned from this package implement
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// Closer, too, even if the Close call is a no-op. This happens in preparation
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// for adding a Close method to the Encoder interface directly in a (mildly
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// breaking) release in the future.
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type Closer interface {
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Close() error
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}
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type encoderCloser struct {
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encode func(*dto.MetricFamily) error
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close func() error
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}
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func (ec encoderCloser) Encode(v *dto.MetricFamily) error {
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return ec.encode(v)
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}
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func (ec encoderCloser) Close() error {
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return ec.close()
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}
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// Negotiate returns the Content-Type based on the given Accept header. If no
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// appropriate accepted type is found, FmtText is returned (which is the
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// Prometheus text format). This function will never negotiate FmtOpenMetrics,
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// as the support is still experimental. To include the option to negotiate
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// FmtOpenMetrics, use NegotiateOpenMetrics.
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func Negotiate(h http.Header) Format {
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escapingScheme := Format(fmt.Sprintf("; escaping=%s", Format(model.NameEscapingScheme.String())))
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for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
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if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
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switch Format(escapeParam) {
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case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
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escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
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default:
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// If the escaping parameter is unknown, ignore it.
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}
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}
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ver := ac.Params["version"]
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if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
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switch ac.Params["encoding"] {
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case "delimited":
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return fmtProtoDelim + escapingScheme
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case "text":
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return fmtProtoText + escapingScheme
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case "compact-text":
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return fmtProtoCompact + escapingScheme
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}
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}
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if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
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return fmtText + escapingScheme
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}
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}
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return fmtText + escapingScheme
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}
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// NegotiateIncludingOpenMetrics works like Negotiate but includes
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// FmtOpenMetrics as an option for the result. Note that this function is
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// temporary and will disappear once FmtOpenMetrics is fully supported and as
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// such may be negotiated by the normal Negotiate function.
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func NegotiateIncludingOpenMetrics(h http.Header) Format {
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escapingScheme := Format(fmt.Sprintf("; escaping=%s", Format(model.NameEscapingScheme.String())))
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for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
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if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
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switch Format(escapeParam) {
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case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
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escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
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default:
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// If the escaping parameter is unknown, ignore it.
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}
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}
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ver := ac.Params["version"]
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if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
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switch ac.Params["encoding"] {
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case "delimited":
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return fmtProtoDelim + escapingScheme
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case "text":
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return fmtProtoText + escapingScheme
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case "compact-text":
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return fmtProtoCompact + escapingScheme
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}
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}
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if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
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return fmtText + escapingScheme
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}
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if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion_0_0_1 || ver == OpenMetricsVersion_1_0_0 || ver == "") {
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switch ver {
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case OpenMetricsVersion_1_0_0:
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return fmtOpenMetrics_1_0_0 + escapingScheme
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default:
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return fmtOpenMetrics_0_0_1 + escapingScheme
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}
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}
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}
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return fmtText + escapingScheme
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}
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// NewEncoder returns a new encoder based on content type negotiation. All
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// Encoder implementations returned by NewEncoder also implement Closer, and
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// callers should always call the Close method. It is currently only required
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// for FmtOpenMetrics, but a future (breaking) release will add the Close method
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// to the Encoder interface directly. The current version of the Encoder
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// interface is kept for backwards compatibility.
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// In cases where the Format does not allow for UTF-8 names, the global
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// NameEscapingScheme will be applied.
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//
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// NewEncoder can be called with additional options to customize the OpenMetrics text output.
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// For example:
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// NewEncoder(w, FmtOpenMetrics_1_0_0, WithCreatedLines())
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//
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// Extra options are ignored for all other formats.
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func NewEncoder(w io.Writer, format Format, options ...EncoderOption) Encoder {
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escapingScheme := format.ToEscapingScheme()
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switch format.FormatType() {
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case TypeProtoDelim:
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return encoderCloser{
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encode: func(v *dto.MetricFamily) error {
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_, err := protodelim.MarshalTo(w, v)
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return err
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},
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close: func() error { return nil },
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}
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case TypeProtoCompact:
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return encoderCloser{
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encode: func(v *dto.MetricFamily) error {
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_, err := fmt.Fprintln(w, model.EscapeMetricFamily(v, escapingScheme).String())
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return err
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},
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close: func() error { return nil },
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}
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case TypeProtoText:
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return encoderCloser{
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encode: func(v *dto.MetricFamily) error {
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_, err := fmt.Fprintln(w, prototext.Format(model.EscapeMetricFamily(v, escapingScheme)))
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return err
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},
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close: func() error { return nil },
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}
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case TypeTextPlain:
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return encoderCloser{
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encode: func(v *dto.MetricFamily) error {
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_, err := MetricFamilyToText(w, model.EscapeMetricFamily(v, escapingScheme))
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return err
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},
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close: func() error { return nil },
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}
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case TypeOpenMetrics:
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return encoderCloser{
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encode: func(v *dto.MetricFamily) error {
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_, err := MetricFamilyToOpenMetrics(w, model.EscapeMetricFamily(v, escapingScheme), options...)
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return err
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},
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close: func() error {
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_, err := FinalizeOpenMetrics(w)
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return err
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},
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}
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}
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panic(fmt.Errorf("expfmt.NewEncoder: unknown format %q", format))
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}
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