Add Nix flake for mcproxyctl

Vendor dependencies and expose mcproxyctl binary via nix build.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vendor/github.com/prometheus/common/expfmt/expfmt.go

@@ -0,0 +1,211 @@
+// Copyright 2015 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package expfmt contains tools for reading and writing Prometheus metrics.
+package expfmt
+
+import (
+	"errors"
+	"strings"
+
+	"github.com/prometheus/common/model"
+)
+
+// Format specifies the HTTP content type of the different wire protocols.
+type Format string
+
+// Constants to assemble the Content-Type values for the different wire
+// protocols. The Content-Type strings here are all for the legacy exposition
+// formats, where valid characters for metric names and label names are limited.
+// Support for arbitrary UTF-8 characters in those names is already partially
+// implemented in this module (see model.ValidationScheme), but to actually use
+// it on the wire, new content-type strings will have to be agreed upon and
+// added here.
+const (
+	TextVersion   = "0.0.4"
+	ProtoType     = `application/vnd.google.protobuf`
+	ProtoProtocol = `io.prometheus.client.MetricFamily`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	ProtoFmt        = ProtoType + "; proto=" + ProtoProtocol + ";"
+	OpenMetricsType = `application/openmetrics-text`
+	//nolint:revive // Allow for underscores.
+	OpenMetricsVersion_0_0_1 = "0.0.1"
+	//nolint:revive // Allow for underscores.
+	OpenMetricsVersion_1_0_0 = "1.0.0"
+
+	// The Content-Type values for the different wire protocols. Do not do direct
+	// comparisons to these constants, instead use the comparison functions.
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeUnknown) instead.
+	FmtUnknown Format = `<unknown>`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeTextPlain) instead.
+	FmtText Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoDelim) instead.
+	FmtProtoDelim Format = ProtoFmt + ` encoding=delimited`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoText) instead.
+	FmtProtoText Format = ProtoFmt + ` encoding=text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	//nolint:revive // Allow for underscores.
+	FmtOpenMetrics_1_0_0 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_1_0_0 + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	//nolint:revive // Allow for underscores.
+	FmtOpenMetrics_0_0_1 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_0_0_1 + `; charset=utf-8`
+)
+
+const (
+	hdrContentType = "Content-Type"
+	hdrAccept      = "Accept"
+)
+
+// FormatType is a Go enum representing the overall category for the given
+// Format. As the number of Format permutations increases, doing basic string
+// comparisons are not feasible, so this enum captures the most useful
+// high-level attribute of the Format string.
+type FormatType int
+
+const (
+	TypeUnknown FormatType = iota
+	TypeProtoCompact
+	TypeProtoDelim
+	TypeProtoText
+	TypeTextPlain
+	TypeOpenMetrics
+)
+
+// NewFormat generates a new Format from the type provided. Mostly used for
+// tests, most Formats should be generated as part of content negotiation in
+// encode.go. If a type has more than one version, the latest version will be
+// returned.
+func NewFormat(t FormatType) Format {
+	switch t {
+	case TypeProtoCompact:
+		return FmtProtoCompact
+	case TypeProtoDelim:
+		return FmtProtoDelim
+	case TypeProtoText:
+		return FmtProtoText
+	case TypeTextPlain:
+		return FmtText
+	case TypeOpenMetrics:
+		return FmtOpenMetrics_1_0_0
+	default:
+		return FmtUnknown
+	}
+}
+
+// NewOpenMetricsFormat generates a new OpenMetrics format matching the
+// specified version number.
+func NewOpenMetricsFormat(version string) (Format, error) {
+	if version == OpenMetricsVersion_0_0_1 {
+		return FmtOpenMetrics_0_0_1, nil
+	}
+	if version == OpenMetricsVersion_1_0_0 {
+		return FmtOpenMetrics_1_0_0, nil
+	}
+	return FmtUnknown, errors.New("unknown open metrics version string")
+}
+
+// WithEscapingScheme returns a copy of Format with the specified escaping
+// scheme appended to the end. If an escaping scheme already exists it is
+// removed.
+func (f Format) WithEscapingScheme(s model.EscapingScheme) Format {
+	var terms []string
+	for _, p := range strings.Split(string(f), ";") {
+		toks := strings.Split(p, "=")
+		if len(toks) != 2 {
+			trimmed := strings.TrimSpace(p)
+			if len(trimmed) > 0 {
+				terms = append(terms, trimmed)
+			}
+			continue
+		}
+		key := strings.TrimSpace(toks[0])
+		if key != model.EscapingKey {
+			terms = append(terms, strings.TrimSpace(p))
+		}
+	}
+	terms = append(terms, model.EscapingKey+"="+s.String())
+	return Format(strings.Join(terms, "; "))
+}
+
+// FormatType deduces an overall FormatType for the given format.
+func (f Format) FormatType() FormatType {
+	toks := strings.Split(string(f), ";")
+	params := make(map[string]string)
+	for i, t := range toks {
+		if i == 0 {
+			continue
+		}
+		args := strings.Split(t, "=")
+		if len(args) != 2 {
+			continue
+		}
+		params[strings.TrimSpace(args[0])] = strings.TrimSpace(args[1])
+	}
+
+	switch strings.TrimSpace(toks[0]) {
+	case ProtoType:
+		if params["proto"] != ProtoProtocol {
+			return TypeUnknown
+		}
+		switch params["encoding"] {
+		case "delimited":
+			return TypeProtoDelim
+		case "text":
+			return TypeProtoText
+		case "compact-text":
+			return TypeProtoCompact
+		default:
+			return TypeUnknown
+		}
+	case OpenMetricsType:
+		if params["charset"] != "utf-8" {
+			return TypeUnknown
+		}
+		return TypeOpenMetrics
+	case "text/plain":
+		v, ok := params["version"]
+		if !ok {
+			return TypeTextPlain
+		}
+		if v == TextVersion {
+			return TypeTextPlain
+		}
+		return TypeUnknown
+	default:
+		return TypeUnknown
+	}
+}
+
+// ToEscapingScheme returns an EscapingScheme depending on the Format. Iff the
+// Format contains a escaping=allow-utf-8 term, it will select NoEscaping. If a valid
+// "escaping" term exists, that will be used. Otherwise, the global default will
+// be returned.
+func (f Format) ToEscapingScheme() model.EscapingScheme {
+	for _, p := range strings.Split(string(f), ";") {
+		toks := strings.Split(p, "=")
+		if len(toks) != 2 {
+			continue
+		}
+		key, value := strings.TrimSpace(toks[0]), strings.TrimSpace(toks[1])
+		if key == model.EscapingKey {
+			scheme, err := model.ToEscapingScheme(value)
+			if err != nil {
+				return model.NameEscapingScheme
+			}
+			return scheme
+		}
+	}
+	return model.NameEscapingScheme
+}