init

.gitignore

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+.DS_Store
+Thumbs.db
+
+.idea
+.vscode
+
+.env
+coverage.out
+bin

.golangci.yaml

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+linters-settings:
+  depguard:
+    rules:
+      logger:
+        deny:
+          - pkg: "github.com/sirupsen/logrus"
+            desc: logging is allowed only by logutils.Log
+  dupl:
+    threshold: 100
+  funlen:
+    lines: -1
+    statements: 50
+  goconst:
+    min-len: 2
+    min-occurrences: 3
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport
+      - ifElseChain
+      - octalLiteral
+      - whyNoLint
+      - unnamedResult
+      - rangeValCopy
+      - hugeParam
+  gocyclo:
+    min-complexity: 15
+  gofmt:
+    rewrite-rules:
+      - pattern: 'interface{}'
+        replacement: 'any'
+  goimports:
+    local-prefixes: github.com/dsbasko/go-cfg
+  gomnd:
+    checks:
+      - argument
+      - case
+      - condition
+      - return
+    ignored-numbers:
+      - '0'
+      - '1'
+      - '2'
+      - '3'
+    ignored-functions:
+      - strings.SplitN
+
+  govet:
+    check-shadowing: true
+    settings:
+      printf:
+        funcs:
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Infof
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Warnf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Errorf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Fatalf
+  misspell:
+    locale: US
+  nolintlint:
+    allow-unused: false
+    require-explanation: false
+    require-specific: false
+  revive:
+    rules:
+      - name: unexported-return
+        disabled: true
+      - name: unused-parameter
+
+linters:
+  disable-all: true
+  enable:
+    - bodyclose
+    - depguard
+    - dogsled
+    - errcheck
+    - exportloopref
+    - funlen
+    - gocheckcompilerdirectives
+    - gochecknoinits
+    - goconst
+    - gocritic
+    - gocyclo
+    - gofmt
+    - goimports
+    - gomnd
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - misspell
+    - nakedret
+    - noctx
+    - nolintlint
+    - revive
+    - staticcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - whitespace
+
+issues:
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - gomnd
+
+    - path: example_test.go
+      linters:
+        - noctx
+        - nolintlint
+        - govet
+        - staticcheck
+
+    - path: pkg/golinters/errcheck.go
+      text: "SA1019: errCfg.Exclude is deprecated: use ExcludeFunctions instead"
+    - path: pkg/commands/run.go
+      text: "SA1019: lsc.Errcheck.Exclude is deprecated: use ExcludeFunctions instead"
+    - path: pkg/commands/run.go
+      text: "SA1019: e.cfg.Run.Deadline is deprecated: Deadline exists for historical compatibility and should not be used."
+
+    - path: pkg/golinters/gofumpt.go
+      text: "SA1019: settings.LangVersion is deprecated: use the global `run.go` instead."
+    - path: pkg/golinters/staticcheck_common.go
+      text: "SA1019: settings.GoVersion is deprecated: use the global `run.go` instead."
+    - path: pkg/lint/lintersdb/manager.go
+      text: "SA1019: (.+).(GoVersion|LangVersion) is deprecated: use the global `run.go` instead."
+    - path: pkg/golinters/unused.go
+      text: "rangeValCopy: each iteration copies 160 bytes \\(consider pointers or indexing\\)"
+    - path: test/(fix|linters)_test.go
+      text: "string `gocritic.go` has 3 occurrences, make it a constant"
+
+run:
+  timeout: 5m
+  skip-dirs:
+    - test/testdata_etc
+    - internal/cache
+    - internal/renameio
+    - internal/robustio

LICENCE.md

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+The MIT License (MIT)
+
+Copyright (c) 2023 Basenko Dmitriy
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Makefile

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+.PHONY: lint install-deps
+.SILENT:
+
+lint:
+	@clear
+	@$(CURDIR)/bin/golangci-lint run -c .golangci.yaml --path-prefix .
+
+install-deps:
+	@clear
+	@GOBIN=$(CURDIR)/bin go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.55.2
+	@go mod tidy
+

README.md

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+# Go Configuration Library
+This project is a Go library for reading configuration data from various sources such as environment variables, command-line flags, and configuration files. The library provides a unified interface for reading configuration data, making it easier to manage and maintain your application's configuration.  
+
+## Attention
+The library uses the [env](github.com/caarlos0/env) and [flaggy](github.com/integrii/flaggy) codebase to work with environment variables and flags. This is a temporary solution, maybe I’ll write my own implementation later. Thanks to the authors of these libraries for the work done!
+
+### Installation
+To install the library, use the go get command:
+```bash
+go get github.com/dsbasko/go-cfg
+```
+
+## Usage
+The library provides several functions for reading configuration data: 
+
+- `ReadEnv(cfg any) error`: Reads environment variables into the provided `cfg` structure. Each field in the `cfg` structure represents an environment variable.  
+- `MustReadEnv(cfg any)`: Similar to `ReadEnv` but panics if the reading process fails.  
+- `ReadFlag(cfg any) error`: Reads command-line flags into the provided `cfg` structure. Each field in the `cfg` structure represents a command-line flag.  
+- `MustReadFlag(cfg any)`: Similar to `ReadFlag` but panics if the reading process fails.  
+- `ReadFile(path string, cfg any) error`: Reads configuration from a file into the provided `cfg` structure. The path parameter is the path to the configuration file. Each field in the `cfg` structure represents a configuration option. Supported file formats include JSON and YAML.
+- `MustReadFile(path string, cfg any)`: Similar to `ReadFile` but panics if the reading process fails.
+
+Here is an example of how to use the library:
+
+```go
+package main
+
+import (
+	"github.com/dsbasko/go-cfg"
+)
+
+type Config struct {
+	Mode string `json:"mode" yaml:"mode" s-flag:"m" flag:"mode" env:"MODE" description:"mode of the application (dev|prod)"`
+	HTTP struct {
+		Host         string `json:"host" yaml:"host" s-flag:"h" flag:"http-host" env:"HTTP_HOST"`
+		Port         int    `json:"port" yaml:"port" s-flag:"p" flag:"http-port" env:"HTTP_PORT"`
+		ReadTimeout  int    `json:"read_timeout" yaml:"read-timeout" flag:"http-read-timeout" env:"HTTP_READ_TIMEOUT"`
+		WriteTimeout int    `json:"write_timeout" yaml:"write-timeout" flag:"http-write-timeout" env:"HTTP_WRITE_TIMEOUT"`
+	} `json:"http" yaml:"http"`
+}
+
+func main() {
+	cfg := Config{}
+
+	gocfg.MustReadFile("configs/config.yaml", &cfg)
+	gocfg.MustReadEnv(&cfg)
+	gocfg.MustReadFlag(&cfg)
+}
+```
+