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dmfed
2021-03-20 21:10:53 +03:00
committed by Dmitry Fedotov
parent 6cc9cd65fb
commit 27cb532ec4
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21
LICENSE Normal file
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MIT License
Copyright (c) 2021 Dmitry Fedotov
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.

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README.md Normal file
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# module conf
**go get code.uint32.ru/tiny/conf** to download.
**import "code.uint32.ru/tiny/conf"** to use in your code.
Module conf implements a very simple config parser with two types of
values: key value pairs and single word options. Each of these must be
put on separate line in a file like this:
```
key1 = value
key2 = value1, value2, value3
option1
option2
```
Values can also be read from any io.Reader or io.ReadCloser. Note that
values in key value pairs mey either be separated with spaces or not.
Typical use case would look like this:
```go
config, err := conf.ParseFile("filename")
if err != nil {
// Means we failed to read from file
// config variable is now nil and unusable
}
value, err := config.Find("mykey")
if err != nil {
// Means that key has not been found
}
// value now holds conf.Setting type which can be accessed directly.
fmt.Println(value.Value)
n, err := value.Float64() // tries to parse float from Setting.Value field.
// if err is nil then n holds float64.
```
Shorter syntax is also available with Get() method which drops errors if
key was not found and simply returns Setting with empty Value field:
```go
listnumbers, err := config.Get("numbers").IntSlice()
// listnumbers holds slice of ints. If err is nil all of found values
// have converted successfully.
```
Note that we'd still like to check for errors in above example even if
we're sure the key exists. This way we'll configrm that all values have been converted.
There is also a GetDefault() method:
```go
def := config.GetDefault("non-existant-key", "myvalue")
fmt.Println(def.Value) // "myvalue"
```
To check whether single-word options were found use:
```go
if config.HasOption("wordoption") {
// do something
}
```
See description of module's types and methods which are
quite self-explanatory.
See also **[https://pkg.go.dev/code.uint32.ru/tiny/conf](https://pkg.go.dev/code.uint32.ru/tiny/conf)** for a complete description of module's
functions.
Below is listing of a working example of a program parsing config (also found **example/main.go** in the repository).
```go
package main
import (
"bytes"
"fmt"
"code.uint32.ru/tiny/conf"
)
var testConf = []byte(`
# commented
port=10000
servers = 10.0.0.1, 10.0.0.2, 10.0.0.3
bool0=0
booltrue = true
distance=13.42
iamsure = hopefully you're not mistaken
float = 13.1984
color`)
func main() {
r := bytes.NewReader(testConf) // creating io.Reader from []byte()
config := conf.ParseReader(r) // we could call conf.ParseFile("filename") here
// First of all we can access parsed values directly:
for key, value := range config.Settings {
fmt.Println(key, value)
}
for opt := range config.Options {
fmt.Println(opt)
}
fmt.Println()
// Find( key string) returns instance of Setting and an
// error if key was not found
//
// type Setting struct {
// Value string // value if found
// }
//
// You can access Setting's Value field (type string) directly.
port, err := config.Find("port")
fmt.Printf("variable port has type: %T, port.Value == %v, type of port.Value is: %T, error returned: %v\n", port, port.Value, port.Value, err)
// We can cast Setting.Value to a desired type including int, float64,
// bool and string. Method will return an error if Setting Value field
// can not be interpreted as desired type.
n, err := port.Int()
fmt.Printf("n has value: %v, type: %T, err: %v\n", n, n, err)
// Another syntax for getting Setting instance is to use Get() method
// which never returns errors. Get will return Setting with empty string
// in Value filed if requested key was now found.
d := config.Get("distance")
distance, err := d.Float64()
fmt.Printf("var distance has value: %v, type: %T, error value: %v\n", distance, distance, err)
// Get() syntax can be is slightly shorter if we're "sure" that key exists in
// the config.
sure := config.Get("iamsure").String() // String method never returns errors
// or simply sure := config.Get("iamsure").Value:
fmt.Println(sure)
// or like this:
fl, _ := config.Get("float").Float64() // we're dropping error here. Bad if value fails to convert.
fmt.Println("fl, _ := config.Get(\"float\").Float64() Value of var fl is:", fl)
// We can access comma-separated values of key like this:
servers := config.Get("servers").StringSlice()
fmt.Println("Found servers:")
for i, s := range servers {
fmt.Println(i+1, "\t", s)
}
// There is also a GetDefault() method which sets output Setting value
// to requested default if key was not found.
def := config.GetDefault("non-existant-key", "myvalue")
fmt.Println(def.Value) // "myvalue"
// You can use HasOption method to find whether single-word options were
// present in the the config
if config.HasOption("color") {
fmt.Println("Hooray, we've found option \"color\"!")
// do something useful
}
// Below code finds two keys with bool values in the Config
// and outputs those.
var t, f bool
t, _ = config.Get("booltrue").Bool()
f, _ = config.Get("bool0").Bool()
fmt.Printf("t's type is: %T, value: %v, f's type is: %T, value: %v\n\n", t, t, f, f)
}
```
Here is the full output of the above code:
```
distance 13.42
iamsure hopefully you're not mistaken
float 13.1984
port 10000
servers 10.0.0.1, 10.0.0.2, 10.0.0.3
bool0 0
booltrue true
color
variable port has type: conf.Setting, port.Value == 10000, type of port.Value is: string, error returned: <nil>
n has value: 10000, type: int, err: <nil>
var distance has value: 13.42, type: float64, error value: <nil>
hopefully you're not mistaken
fl, _ := config.Get("float").Float64() Value of var fl is: 13.1984
Found servers:
1 10.0.0.1
2 10.0.0.2
3 10.0.0.3
Hooray, we've found option "color"!
t's type is: bool, value: true, f's type is: bool, value: false
```

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conf_test.go Normal file
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package conf
import (
"bytes"
"testing"
)
var testConf = []byte(`port=10000
# removed
two = two words
commas = abc, def, ghi
token=test
bool1=1
bool2=true
editor = vim
distance=13.42
floats=0.5,2.37,6
floatswithstring = 0.5, hello, 0.9
no missedme
color`)
func TestPackage(t *testing.T) {
r := bytes.NewReader(testConf)
c := parseReader(r)
if _, err := c.Get("floatswithstring").Float64Slice(); err == nil {
t.Log("Float64Slice accepting incorrect values")
t.Fail()
}
if _, err := c.Get("floats").Float64Slice(); err != nil {
t.Log("Float64Slice failing on correct values")
t.Fail()
}
if v := c.Get("token").String(); v != "test" {
t.Log("failed finding key value")
t.Fail()
}
if v := c.Get("editor").String(); v != "vim" {
t.Log("failed finding key value")
t.Fail()
}
if v, _ := c.Get("port").Int(); v != 10000 {
t.Log("failed finding int")
t.Fail()
}
if v, _ := c.Get("distance").Float64(); v != 13.42 {
t.Log("failed finding key value")
t.Fail()
}
if c.HasOption("color") != true {
t.Log("failed finding option")
t.Fail()
}
if v, _ := c.Get("bool1").Bool(); v != true {
t.Log("failed finding bool1 value")
t.Fail()
}
if v, _ := c.Get("bool2").Bool(); v != true {
t.Log("failed finding bool2 value")
t.Fail()
}
if v := c.Get("two").String(); v != "two words" {
t.Log("failed finding key value")
t.Fail()
}
if v := c.Get("commas").String(); v != "abc, def, ghi" {
t.Log("failed finding key value")
t.Fail()
}
if v := c.Get("nonexistent").String(); v != "" {
t.Log("returned non-empty string for nonexistent key")
t.Fail()
}
if c.HasOption("removed") {
t.Log("commented out line shows up in config")
t.Fail()
}
splitted := c.Get("commas").StringSlice()
if len(splitted) != 3 {
t.Log("could not split string")
t.Fail()
}
abc := splitted[0]
ghi := splitted[2]
if abc != "abc" || ghi != "ghi" {
t.Log("Split() returned incorrect values")
t.Fail()
}
if c.HasOption("no") != true {
t.Log("should capture one option per line even if line holds two")
t.Fail()
}
if c.HasOption("missedme") == true {
t.Log("should only capture one option per line")
t.Fail()
}
st := Setting{}
if v, err := st.Float64(); v != 0.0 || err == nil {
t.Log("empty string erroneously converts to float")
t.Fail()
}
if def := c.GetDefault("non-existant-key", "myvalue"); def.Value != "myvalue" {
t.Log("GetDefault fails to apply default value")
t.Fail()
}
}

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config.go Normal file
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// module conf
//
// import "code.uint32.ru/tiny/conf"
//
// Module conf implements a very simple config parser with two types of
// values: key value pairs and single word options. Each of these must be
// put on separate line in a file like this:
//
// key1 = value
// key2 = value1, value2, value3
// key3=v1,v2,v3
// option1
// option2
//
// Values can also be read from any io.Reader or io.ReadCloser. Note that
// values in key value pairs mey either be separated with spaces or not.
// Typical use case would look like this:
//
// config, err := conf.ParseFile("filename")
// if err != nil {
// // Means we failed to read from file
// // config variable is now nil and unusable
// }
// value, err := config.Find("mykey")
// if err != nil {
// // Means that key has not been found
// }
// // value now holds conf.Setting.
// n, err := value.Float64() // tries to parse float from Setting.Value field.
// //if err is nil then n holds float64.
//
// There is also a quicker Get() method which returns no errors
// ("i'm feeling lucky" way to lookup values). If it does not find
// requested key, the returned Setting has empty string in Value field.
//
// value2 := config.Get("otherkey")
// mybool, err := value2.Bool() // tries to interpret Setting.Value field as bool
// // mybool now holds boolean if "otherkey" was found and error returned
// // by Bool() method is nil.
//
// Even shorter syntax would be:
//
// listnumbers, err := config.Get("numbers").IntSlice()
// // Note that we'd still like to check for errors even if
// // we're sure the key exists to make sure all values are converted.
// // listnumbers holds slice of ints. If err is nil all of found values
// // have been converted successfully.
//
// To check whether single-word options were found use:
//
// if config.HasOption("wordoption") {
// // do something
// }
//
// See description of module's other methods which are
// quite self-explanatory.
package conf
// Config holds parsed keys and values. Settings and Options can be
// accessed with Config.Settings and Config.Options maps directly.
type Config struct {
// Settings store key value pairs ("key = value" in config file)
// all key value pairs found when parsing input are accumulated in this map.
Settings map[string]string
// Options map stores single word options ("option" in config file)
Options map[string]struct{}
}
// Find looks up a Setting and returns it. If returned error is not nil
// the requested key was not found and returned Setting has empty string in Value
// field.
func (c *Config) Find(key string) (s Setting, err error) {
v, ok := c.Settings[key]
if !ok {
err = ErrNotFound
}
s.Value = v
return
}
// Get returns a Setting. If key was not found the returned Setting Value
// will be empty string.
func (c *Config) Get(key string) (s Setting) {
s.Value = c.Settings[key]
return
}
// GetDefault looks up a Setting with requested key.
// If lookup fails it returns Setting with Value field set to def.
func (c *Config) GetDefault(key, def string) (s Setting) {
v, ok := c.Settings[key]
switch ok {
case true:
s.Value = v
default:
s.Value = def
}
return
}
// HasOption returns true if line:
//
// "key"
//
// was found in the parsed file
func (c *Config) HasOption(option string) (exists bool) {
_, exists = c.Options[option]
return
}

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example/main.go Normal file
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package main
import (
"bytes"
"fmt"
"code.uint32.ru/tiny/conf"
)
var testConf = []byte(`
# commented
port=10000
servers = 10.0.0.1, 10.0.0.2, 10.0.0.3
bool0=0
booltrue = true
distance=13.42
iamsure = hopefully you're not mistaken
float = 13.1984
color`)
func main() {
r := bytes.NewReader(testConf) // creating io.Reader from []byte()
config := conf.ParseReader(r) // we could call conf.ParseFile("filename") here
// First of all we can access parsed values directly:
for key, value := range config.Settings {
fmt.Println(key, value)
}
for opt := range config.Options {
fmt.Println(opt)
}
fmt.Println()
// Find( key string) returns instance of Setting and an
// error if key was not found
//
// type Setting struct {
// Value string // value if found
// }
//
// You can access Setting's Value field (type string) directly.
port, err := config.Find("port")
fmt.Printf("variable port has type: %T, port.Value == %v, type of port.Value is: %T, error returned: %v\n", port, port.Value, port.Value, err)
// We can cast Setting.Value to a desired type including int, float64,
// bool and string. Method will return an error if Setting Value field
// can not be interpreted as desired type.
n, err := port.Int()
fmt.Printf("n has value: %v, type: %T, err: %v\n", n, n, err)
// Another syntax for getting Setting instance is to use Get() method
// which never returns errors. Get will return Setting with empty string
// in Value filed if requested key was now found.
d := config.Get("distance")
distance, err := d.Float64()
fmt.Printf("var distance has value: %v, type: %T, error value: %v\n", distance, distance, err)
// Get() syntax can be is slightly shorter if we're "sure" that key exists in
// the config.
sure := config.Get("iamsure").String() // String method never returns errors
// or simply sure := config.Get("iamsure").Value:
fmt.Println(sure)
// or like this:
fl, _ := config.Get("float").Float64() // we're dropping error here. Bad if value fails to convert.
fmt.Println("fl, _ := config.Get(\"float\").Float64() Value of var fl is:", fl)
// We can access comma-separated values of key like this:
servers := config.Get("servers").StringSlice()
fmt.Println("Found servers:")
for i, s := range servers {
fmt.Println(i+1, "\t", s)
}
// There is also a GetDefault() method
def := config.GetDefault("non-existant-key", "myvalue")
fmt.Println(def.Value) // "myvalue"
// You can use HasOption method to find whether single-word options were
// present in the the config
if config.HasOption("color") {
fmt.Println("Hooray, we've found option \"color\"!")
// do something useful
}
// Below code finds two keys with bool values in the Config
// and outputs those.
var t, f bool
t, _ = config.Get("booltrue").Bool()
f, _ = config.Get("bool0").Bool()
fmt.Printf("t's type is: %T, value: %v, f's type is: %T, value: %v\n\n", t, t, f, f)
}

4
go.mod
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@@ -1,3 +1,3 @@
module github.com/dmfed/conf
module code.uint32.ru/tiny/conf
go 1.16
go 1.24

0
go.sum Normal file
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67
parser.go
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@@ -5,67 +5,62 @@ import (
"io"
"os"
"regexp"
"strconv"
"strings"
)
var (
configKeyValueRe = regexp.MustCompile(`(\w+) *= *(.+)\b[\t| |\n]*`)
configOptionRe = regexp.MustCompile(`(\w+)`)
configKeyValueRe = regexp.MustCompile(`(\w+) *= *(.+)\b[\t| |\n]*`)
configOptionRe = regexp.MustCompile(`(\w+)`)
configCommentedOut = "#"
)
type Config struct {
Values map[string]string
}
func (c *Config) Get(key string) (s string) {
if val, ok := c.Values[key]; ok {
s = val
}
return
}
func (c *Config) GetBool(key string) (b bool) {
_, b = c.Values[key]
return
}
func (c *Config) GetInt(key string) (n int) {
if val, ok := c.Values[key]; ok {
num, err := strconv.Atoi(val)
if err == nil {
n = num
}
}
return
}
func Parse(filename string) (*Config, error) {
// ParseFile reads values from file. It returns nil and error if os.Open(filename) fails.
// It would be wise to always check returned error.
// ParseFile captures two types of values: "key = value" and "option". Either key value pair or
// option must be put in its own line in the file.
// Key or option must be a single word. In example line:
// "option1 option2"
// only option1 will be captured. option2 needs to be in a separate line in the file to take effect.
// In line "key = value1,value2,value3" all of value1, value2, and value3 will be
// captured. They can be later accesed separately with Setting's Split() method.
func ParseFile(filename string) (*Config, error) {
file, err := os.Open(filename)
if err != nil {
return nil, err
}
defer file.Close()
c := parseReader(file)
return c, nil
return parseReader(file), nil
}
// ParseReader reads from r and returns Config. See also ParseFile.
func ParseReader(r io.Reader) *Config {
return parseReader(r)
}
// ParseReadCloser reads from r, returns Config and calls r.Close().
// See also ParseFile.
func ParseReadCloser(r io.ReadCloser) *Config {
defer r.Close()
return parseReader(r)
}
func parseReader(r io.Reader) *Config {
var c Config
c.Values = make(map[string]string)
c.Settings = make(map[string]string)
c.Options = make(map[string]struct{})
scanner := bufio.NewScanner(r)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "#") {
if strings.HasPrefix(line, configCommentedOut) {
continue
}
switch {
case configKeyValueRe.MatchString(line):
kvpair := configKeyValueRe.FindStringSubmatch(line)
c.Values[kvpair[1]] = kvpair[2]
c.Settings[kvpair[1]] = kvpair[2]
case configOptionRe.MatchString(line):
opt := configOptionRe.FindString(line)
c.Values[opt] = ""
c.Options[opt] = struct{}{}
}
}
return &c

31
parser_test.go
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package conf
import (
"bytes"
"fmt"
"testing"
)
var testConf = []byte(`network
server=10.0.0.10
port=10000
token=test
editor=vim
color`)
func TestParser(t *testing.T) {
r := bytes.NewReader(testConf)
c := parseReader(r)
if c.Get("token") != "test" {
fmt.Println("failed finding key value")
t.Fail()
}
if c.GetInt("port") != 10000 {
fmt.Println("failed finding int")
t.Fail()
}
if c.GetBool("color") != true {
fmt.Println("failed finding bool")
t.Fail()
}
}

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settings.go Normal file
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package conf
import (
"errors"
"strconv"
"strings"
)
var (
ErrNotFound = errors.New("key not found")
ErrParsingBool = errors.New("value can not be interpreted as bool")
ErrCouldNotConvert = errors.New("could not cast one or more values to required type")
)
var valuesSeparator = ","
var boolMap = map[string]bool{
// what evaluates to true
"true": true,
"t": true,
"1": true,
"yes": true,
"on": true,
// what evaluates to false
"false": false,
"f": false,
"0": false,
"no": false,
"off": false,
}
// Setting represents key-value pair read from config file.
// It's Value field holds the value of key parsed from the configuration
type Setting struct {
Value string
}
// Int converts Setting Value to int. Returned error
// will be non nil if convesion failed.
func (st Setting) Int() (int, error) {
return parseInt(st.Value)
}
// IntSlice splits Setting Value (separator is ",") and adds
// each of resulting values to []int if possible.
// If one or more values can not be converted to float64 those will be dropped
// and method will return conf.ErrCouldNotConvert.
// Check error to be sure that all required values were parsed.
func (st Setting) IntSlice() ([]int, error) {
return parseIntSlice(st.Value, valuesSeparator)
}
/* func (st Setting) split(sep string) Setting {
st.sep = sep //Choose separator to split values ?
return st
} */
// Float64 converts Setting Value to float64. Returned error
// will be non nil if convesion failed.
func (st Setting) Float64() (float64, error) {
return parseFloat64(st.Value)
}
// Float64Slice splits Setting Value (separator is ",") and adds
// each of resulting values to []float64 if possible.
// If one or more values can not be converted to float64 those will be dropped
// and method will return conf.ErrCouldNotConvert.
// Check error to be sure that all required values were parsed.
func (st Setting) Float64Slice() ([]float64, error) {
return parseFloat64Slice(st.Value, valuesSeparator)
}
// String returns option Value as string
// This method also implements Stringer interface from fmt module
func (st Setting) String() string {
return st.Value
}
// StringSlice splits Setting's Value (separator is ",") and adds
// each of resulting values to []string trimming leading and trailing spaces
// from each string.
func (st Setting) StringSlice() []string {
return tidySplit(st.Value, valuesSeparator)
}
// Bool tries to interpret Setting's Value as bool
// "1", "true", "on", "yes" (case insensitive) yields true
// "0", "false", "off", "no" (case insensitive) yields false
// If nothing matches will return false and conf.ErrParsingBool
func (st Setting) Bool() (bool, error) {
return parseBool(st.Value)
}
func parseInt(s string) (n int, err error) {
n, err = strconv.Atoi(s)
return
}
func parseIntSlice(s, sep string) ([]int, error) {
var (
n int
err error
slice []int
digits []string
)
digits = tidySplit(s, sep)
for _, d := range digits {
n, err = strconv.Atoi(d)
if err != nil {
err = ErrCouldNotConvert
break
}
slice = append(slice, n)
}
return slice, err
}
func parseFloat64(s string) (n float64, err error) {
n, err = strconv.ParseFloat(s, 64)
return
}
func parseFloat64Slice(s, sep string) ([]float64, error) {
var (
n float64
err error
slice []float64
digits []string
)
digits = tidySplit(s, sep)
for _, d := range digits {
n, err = strconv.ParseFloat(d, 64)
if err != nil {
err = ErrCouldNotConvert
break
}
slice = append(slice, n)
}
return slice, err
}
func parseBool(s string) (value bool, err error) {
s = strings.ToLower(s)
value, ok := boolMap[s]
if !ok {
err = ErrParsingBool
}
return
}
func tidySplit(s, sep string) []string {
splitted := strings.Split(s, sep)
for i, str := range splitted {
splitted[i] = strings.Trim(str, " ")
}
return splitted
}