Cleanup related to context refactor (#9988)

utils/fileutils/fileutils.go

@@ -0,0 +1,99 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package fileutils
+
+import (
+	"os"
+	"path/filepath"
+)
+
+var (
+	commonBaseSearchPaths = []string{
+		".",
+		"..",
+		"../..",
+		"../../..",
+	}
+)
+
+func FindPath(path string, baseSearchPaths []string, filter func(os.FileInfo) bool) string {
+	if filepath.IsAbs(path) {
+		if _, err := os.Stat(path); err == nil {
+			return path
+		}
+
+		return ""
+	}
+
+	searchPaths := []string{}
+	searchPaths = append(searchPaths, baseSearchPaths...)
+
+	// Additionally attempt to search relative to the location of the running binary.
+	var binaryDir string
+	if exe, err := os.Executable(); err == nil {
+		if exe, err = filepath.EvalSymlinks(exe); err == nil {
+			if exe, err = filepath.Abs(exe); err == nil {
+				binaryDir = filepath.Dir(exe)
+			}
+		}
+	}
+	if binaryDir != "" {
+		for _, baseSearchPath := range baseSearchPaths {
+			searchPaths = append(
+				searchPaths,
+				filepath.Join(binaryDir, baseSearchPath),
+			)
+		}
+	}
+
+	for _, parent := range searchPaths {
+		found, err := filepath.Abs(filepath.Join(parent, path))
+		if err != nil {
+			continue
+		} else if fileInfo, err := os.Stat(found); err == nil {
+			if filter != nil {
+				if filter(fileInfo) {
+					return found
+				}
+			} else {
+				return found
+			}
+		}
+	}
+
+	return ""
+}
+
+// FindFile looks for the given file in nearby ancestors relative to the current working
+// directory as well as the directory of the executable.
+func FindFile(path string) string {
+	return FindPath(path, commonBaseSearchPaths, func(fileInfo os.FileInfo) bool {
+		return !fileInfo.IsDir()
+	})
+}
+
+// fileutils.FindDir looks for the given directory in nearby ancestors relative to the current working
+// directory as well as the directory of the executable, falling back to `./` if not found.
+func FindDir(dir string) (string, bool) {
+	found := FindPath(dir, commonBaseSearchPaths, func(fileInfo os.FileInfo) bool {
+		return fileInfo.IsDir()
+	})
+	if found == "" {
+		return "./", false
+	}
+
+	return found, true
+}
+
+// FindConfigFile attempts to find an existing configuration file. fileName can be an absolute or
+// relative path or name such as "/opt/mattermost/config.json" or simply "config.json". An empty
+// string is returned if no configuration is found.
+func FindConfigFile(fileName string) (path string) {
+	found := FindFile(filepath.Join("config", fileName))
+	if found == "" {
+		found = FindPath(fileName, []string{"."}, nil)
+	}
+
+	return found
+}