chore: vendor

vendor/go.opentelemetry.io/otel/sdk/resource/os_release_unix.go

@@ -0,0 +1,143 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+//go:build aix || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+// +build aix dragonfly freebsd linux netbsd openbsd solaris zos
+
+package resource // import "go.opentelemetry.io/otel/sdk/resource"
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+// osRelease builds a string describing the operating system release based on the
+// properties of the os-release file. If no os-release file is found, or if the
+// required properties to build the release description string are missing, an empty
+// string is returned instead. For more information about os-release files, see:
+// https://www.freedesktop.org/software/systemd/man/os-release.html
+func osRelease() string {
+	file, err := getOSReleaseFile()
+	if err != nil {
+		return ""
+	}
+
+	defer file.Close()
+
+	values := parseOSReleaseFile(file)
+
+	return buildOSRelease(values)
+}
+
+// getOSReleaseFile returns a *os.File pointing to one of the well-known os-release
+// files, according to their order of preference. If no file can be opened, it
+// returns an error.
+func getOSReleaseFile() (*os.File, error) {
+	return getFirstAvailableFile([]string{"/etc/os-release", "/usr/lib/os-release"})
+}
+
+// parseOSReleaseFile process the file pointed by `file` as an os-release file and
+// returns a map with the key-values contained in it. Empty lines or lines starting
+// with a '#' character are ignored, as well as lines with the missing key=value
+// separator. Values are unquoted and unescaped.
+func parseOSReleaseFile(file io.Reader) map[string]string {
+	values := make(map[string]string)
+	scanner := bufio.NewScanner(file)
+
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if skip(line) {
+			continue
+		}
+
+		key, value, ok := parse(line)
+		if ok {
+			values[key] = value
+		}
+	}
+
+	return values
+}
+
+// skip returns true if the line is blank or starts with a '#' character, and
+// therefore should be skipped from processing.
+func skip(line string) bool {
+	line = strings.TrimSpace(line)
+
+	return len(line) == 0 || strings.HasPrefix(line, "#")
+}
+
+// parse attempts to split the provided line on the first '=' character, and then
+// sanitize each side of the split before returning them as a key-value pair.
+func parse(line string) (string, string, bool) {
+	k, v, found := strings.Cut(line, "=")
+
+	if !found || len(k) == 0 {
+		return "", "", false
+	}
+
+	key := strings.TrimSpace(k)
+	value := unescape(unquote(strings.TrimSpace(v)))
+
+	return key, value, true
+}
+
+// unquote checks whether the string `s` is quoted with double or single quotes
+// and, if so, returns a version of the string without them. Otherwise it returns
+// the provided string unchanged.
+func unquote(s string) string {
+	if len(s) < 2 {
+		return s
+	}
+
+	if (s[0] == '"' || s[0] == '\'') && s[0] == s[len(s)-1] {
+		return s[1 : len(s)-1]
+	}
+
+	return s
+}
+
+// unescape removes the `\` prefix from some characters that are expected
+// to have it added in front of them for escaping purposes.
+func unescape(s string) string {
+	return strings.NewReplacer(
+		`\$`, `$`,
+		`\"`, `"`,
+		`\'`, `'`,
+		`\\`, `\`,
+		"\\`", "`",
+	).Replace(s)
+}
+
+// buildOSRelease builds a string describing the OS release based on the properties
+// available on the provided map. It favors a combination of the `NAME` and `VERSION`
+// properties as first option (falling back to `VERSION_ID` if `VERSION` isn't
+// found), and using `PRETTY_NAME` alone if some of the previous are not present. If
+// none of these properties are found, it returns an empty string.
+//
+// The rationale behind not using `PRETTY_NAME` as first choice was that, for some
+// Linux distributions, it doesn't include the same detail that can be found on the
+// individual `NAME` and `VERSION` properties, and combining `PRETTY_NAME` with
+// other properties can produce "pretty" redundant strings in some cases.
+func buildOSRelease(values map[string]string) string {
+	var osRelease string
+
+	name := values["NAME"]
+	version := values["VERSION"]
+
+	if version == "" {
+		version = values["VERSION_ID"]
+	}
+
+	if name != "" && version != "" {
+		osRelease = fmt.Sprintf("%s %s", name, version)
+	} else {
+		osRelease = values["PRETTY_NAME"]
+	}
+
+	return osRelease
+}