Restructure the code a bit.

Add a more complete wrapper function called Configure and ConfigureWithDefaults.
Add ability to write a configmap back to a new file.
Changed my mind about multiple equals signs because some data like base64 uses equals signs.
Added more tests.
Bump to version 0.1.0 to signal closer to completeness/stability.
Changed domain name from gitea.wisellama.rocks to git.wisellama.rocks.

Makefile

@@ -1,8 +1,9 @@
 all: linter test
 
 test:
-	go test ./
+	go test
 
+lint: linter
 linter:
 	golangci-lint run
 

Readme.md

@@ -1,16 +1,18 @@
 # gosimpleconf
 
 ```sh
-go get gitea.wisellama.rocks/Wisellama/gosimpleconf@v0.0.4
+go get git.wisellama.rocks/Wisellama/gosimpleconf@v0.1.0
 ```
 
-This is a small library for parsing super simple configuration files.
+This is a small library for parsing super simple configuration files
+similar to Unix conf files.
 
 It expects a file with the following format:
 * Lines with key-values pairs separated by `=` (e.g. `foo = bar`)
 * Lines that start with `#` are ignored (used for comments)
-* Empty and whitespace-only lines are ignore
-* Lines with data that don't have an `=` will cause an error.
+* Empty and whitespace-only lines are ignored
+* Lines with some data but no `=` will cause an error.
+* Lines with multiple `=` are split on the literal first `=` seen, any remaining are part of the value.
 
 The key-values pairs are simply parsed as strings and plopped into a
 map for you to do whatever your program wants with them. If you need a
@@ -25,15 +27,21 @@ url = www.wisellama.rocks
 number_of_widgets = 1337
 pi = 3.141592653589793238462643383
 environment = production
+
 # Quotes are optional
 name = Dude guy
 description = "Just some dude it was"
+
+# Additional equals are just part of the value
+base64_tacos = dGFjb3M=
+a=b=c
+# key: 'a', value: 'b=c'
 ```
 
 Then to load that config file into a map:
 
 ```go
-configMap, err := gosimpleconf.Load("file.conf")
+configMap, err := gosimpleconf.Configure("file.conf")
 ```
 
 Then everything is a string. You can parse it as needed.
@@ -42,19 +50,43 @@ var piStr string = configMap["pi"]
 pi, err := strconv.ParseFloat(value, 64)
 ```
 
-To override values with cli flags, after parsing the conf file you can
-use these functions to also parse the flags:
-```go
-flagMap := SetupFlagOverrides(configMap)
-configMap = ParseFlags(configMap, flagmap)
-```
+### Command-Line Flag Overrides
 
-Then you could, for example, override the url value without modifying
-the config file:
-```go
+By default, the `Configure()` function will figure out which keys
+exist in the config map and set those as cli flags that you can
+override. For example, with the config file above, you could override
+the `url` key with a cli flag:
+```sh
 ./program --url=newthing.wisellama.rocks
 ```
 
+If you don't want to support cli flag overrides, you can directly call
+`ReadFile("file.conf")` instead.
+
+If you want to support other cli flags that don't map to a config
+setting, they must be set up before calling `Configure()`. This is
+because the `ParseFlags()` function calls `flag.Parse()` to get all
+the values for the config map overrides. You could also work around
+this by calling `ReadFile` and `ParseFlags` yourself and add your
+other logic in between the two calls.
+
+### Default Config
+
+You can specify a default configuration to return if the given config
+file doesn't exist. Here's an example:
+
+```go
+defaultConfig := gosimpleconf.ConfigMap{
+	"game.title":      "Some Game",
+	"log.writeToFile": "false",
+}
+configMap, err := gosimpleconf.ConfigureWithDefaults("file_that_doesnt_exist.conf", defaultConfig)
+```
+
+Then if the config file can't be found, the default config map values
+will be used instead. You can still override the default values with
+cli flags.
+
 ## Why?
 
 I've always seen configuration files similar to this show up in

config_file.go

@@ -0,0 +1,95 @@
+package gosimpleconf
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+type ConfigMap map[string]string
+
+func Load(filename string) (ConfigMap, error) {
+	return ReadFile(filename)
+}
+
+func ReadFile(filename string) (ConfigMap, error) {
+	var err error
+
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	parsedMap, err := parseFile(file)
+	if err != nil {
+		return nil, err
+	}
+
+	return parsedMap, nil
+}
+
+func WriteFile(filename string, configMap ConfigMap) error {
+	file, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	for k, v := range configMap {
+		fmt.Fprintf(file, "%s = %s\n", k, v)
+	}
+
+	return nil
+}
+
+func parseFile(config io.Reader) (ConfigMap, error) {
+	var err error
+	parsedMap := make(ConfigMap)
+
+	scanner := bufio.NewScanner(config)
+	for scanner.Scan() {
+		line := scanner.Text()
+		trimmed := strings.TrimSpace(line)
+		if len(trimmed) == 0 {
+			// ignore empty lines
+			continue
+		}
+
+		if trimmed[0] == '#' {
+			// ignore comments
+			continue
+		}
+
+		split := strings.Split(trimmed, "=")
+		if len(split) < 2 {
+			return nil, fmt.Errorf("failed to parse config line: %v", trimmed)
+		}
+
+		key := trimToken(split[0])
+
+		value := strings.Join(split[1:], "=") // Re-add any ='s that were part of the value
+		value = trimToken(value)
+
+		parsedMap[key] = value
+	}
+
+	if err = scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return parsedMap, nil
+}
+
+func trimToken(value string) string {
+	// Trim off whitespace
+	v := strings.TrimSpace(value)
+
+	// Trim off any surrounding quotes, everything is a string anyway
+	v = strings.TrimPrefix(v, "\"")
+	v = strings.TrimSuffix(v, "\"")
+
+	return v
+}

config_file_test.go

@@ -0,0 +1,104 @@
+package gosimpleconf
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseWithValidConfig(t *testing.T) {
+	var err error
+	configFileStr := `
+# Some config file
+
+foo=bar
+asdf = 1234
+
+   # Things
+wat.wat= thing
+foo.wat =stuff
+
+immaempty=
+
+technically valid = haha hmm...
+
+#Done
+`
+	configFile := strings.NewReader(configFileStr)
+
+	expectedMap := make(ConfigMap)
+	expectedMap["foo"] = "bar"
+	expectedMap["asdf"] = "1234"
+	expectedMap["wat.wat"] = "thing"
+	expectedMap["foo.wat"] = "stuff"
+	expectedMap["immaempty"] = ""
+	expectedMap["technically valid"] = "haha hmm..."
+
+	parsedMap, err := parseFile(configFile)
+	if err != nil {
+		t.Errorf("failed while parsing the file")
+	}
+
+	validateMap(t, parsedMap, expectedMap)
+}
+
+func TestParseWithNoEquals(t *testing.T) {
+	var err error
+	configFileStr := `
+Something here with no equals to split on
+`
+	configFile := strings.NewReader(configFileStr)
+
+	_, err = parseFile(configFile)
+	if err == nil {
+		t.Errorf("parse did not thrown an error when it was supposed to")
+	}
+}
+
+func TestParseWithExtraQuotes(t *testing.T) {
+	var err error
+	configFileStr := `
+	some.name = "This is in quotes"
+	extra.quotes = ""This will keep the quotes""
+	internal.quotes = "Some "thing" is here"
+	"This should work too" = shrug I guess
+	`
+
+	configFile := strings.NewReader(configFileStr)
+
+	expectedMap := make(ConfigMap)
+	expectedMap["some.name"] = "This is in quotes"
+	expectedMap["extra.quotes"] = "\"This will keep the quotes\""
+	expectedMap["internal.quotes"] = "Some \"thing\" is here"
+	expectedMap["This should work too"] = "shrug I guess"
+
+	configMap, err := parseFile(configFile)
+	if err != nil {
+		t.Errorf("failed while parsing the file")
+	}
+
+	validateMap(t, configMap, expectedMap)
+}
+
+func TestParseExtraEquals(t *testing.T) {
+	configFileStr := `
+foo=bar=true
+base64_tacos = dGFjb3M=
+"equals=splits" the key/value, quotes and other =equals= don't matter
+yup=soup
+`
+
+	configFile := strings.NewReader(configFileStr)
+
+	expectedMap := make(ConfigMap)
+	expectedMap["foo"] = "bar=true"
+	expectedMap["base64_tacos"] = "dGFjb3M="
+	expectedMap["equals"] = "splits\" the key/value, quotes and other =equals= don't matter"
+	expectedMap["yup"] = "soup"
+
+	configMap, err := parseFile(configFile)
+	if err != nil {
+		t.Errorf("failed while parsing the file")
+	}
+
+	validateMap(t, configMap, expectedMap)
+}

conversions.go

@@ -0,0 +1,36 @@
+package gosimpleconf
+
+import (
+	"log"
+	"strconv"
+)
+
+func Bool(value string) bool {
+	v, err := strconv.ParseBool(value)
+	if err != nil {
+		log.Printf("error parsing bool %v - %v\n", v, err)
+		v = false
+	}
+
+	return v
+}
+
+func Int64(value string) int64 {
+	v, err := strconv.ParseInt(value, 10, 64)
+	if err != nil {
+		log.Printf("error parsing int %v - %v\n", v, err)
+		v = 0
+	}
+
+	return v
+}
+
+func Float64(value string) float64 {
+	v, err := strconv.ParseFloat(value, 64)
+	if err != nil {
+		log.Printf("error parsing float %v - %v\n", v, err)
+		v = 0.0
+	}
+
+	return v
+}

flag_overrides.go

@@ -0,0 +1,28 @@
+package gosimpleconf
+
+import "flag"
+
+type FlagMap map[string]*string
+
+func SetupFlagOverrides(configMap ConfigMap) FlagMap {
+	flagMap := make(FlagMap)
+	for k, v := range configMap {
+		f := flag.String(k, v, "")
+		flagMap[k] = f
+	}
+
+	return flagMap
+}
+
+func ParseFlags(configMap ConfigMap, flagMap FlagMap) ConfigMap {
+	flag.Parse()
+
+	for k, v := range flagMap {
+		if v != nil && len(*v) > 0 {
+			configMap[k] = trimToken(*v)
+		}
+	}
+
+	return configMap
+
+}

flag_overrides_test.go

@@ -0,0 +1,41 @@
+package gosimpleconf
+
+import (
+	"flag"
+	"strings"
+	"testing"
+)
+
+func TestFlagOverrides(t *testing.T) {
+	var err error
+	configFileStr := `
+foo=bar
+asdf = 1234
+foo.wat =stuff
+immaempty=
+`
+	configFile := strings.NewReader(configFileStr)
+
+	expectedMap := make(ConfigMap)
+	expectedMap["foo"] = "bar"
+	expectedMap["asdf"] = "1234"
+	// expect to override the 'foo.wat' value with a cli flag
+	expectedMap["foo.wat"] = "iwasoverridden"
+	expectedMap["immaempty"] = ""
+
+	configMap, err := parseFile(configFile)
+	if err != nil {
+		t.Errorf("failed while parsing the file")
+	}
+
+	flagMap := SetupFlagOverrides(configMap)
+
+	err = flag.Set("foo.wat", "iwasoverridden")
+	if err != nil {
+		t.Errorf("failed to set cli flag override")
+	}
+
+	configMap = ParseFlags(configMap, flagMap)
+
+	validateMap(t, configMap, expectedMap)
+}

go.mod

@@ -1,3 +1,3 @@
-module gitea.wisellama.rocks/Wisellama/gosimpleconf
+module git.wisellama.rocks/Wisellama/gosimpleconf
 
 go 1.17

gosimpleconf.go

@@ -1,112 +1,31 @@
 package gosimpleconf
 
-import (
-	"bufio"
-	"flag"
-	"fmt"
-	"io"
-	"log"
-	"os"
-	"strconv"
-	"strings"
-)
+import "os"
 
-type ConfigMap map[string]string
-type FlagMap map[string]*string
-
-func Load(filename string) (ConfigMap, error) {
+func Configure(filename string) (ConfigMap, error) {
 	var err error
 
-	file, err := os.Open(filename)
-	if err != nil {
-		return nil, err
-	}
-	defer file.Close()
-
-	parsedMap, err := parseFile(file)
+	configMap, err := ReadFile(filename)
 	if err != nil {
 		return nil, err
 	}
 
-	return parsedMap, nil
+	flagMap := SetupFlagOverrides(configMap)
+	configMap = ParseFlags(configMap, flagMap)
+
+	return configMap, nil
 }
 
-func SetupFlagOverrides(configMap ConfigMap) FlagMap {
-	flagMap := make(FlagMap)
-	for k, v := range configMap {
-		f := flag.String(k, v, "")
-		flagMap[k] = f
-	}
-
-	return flagMap
-}
-
-func ParseFlags(configMap ConfigMap, flagMap FlagMap) ConfigMap {
-	flag.Parse()
-
-	for k, v := range flagMap {
-		if v != nil && len(*v) > 0 {
-			configMap[k] = trimToken(*v)
-		}
-	}
-
-	return configMap
-
-}
-
-func Bool(value string) bool {
-	v, err := strconv.ParseBool(value)
-	if err != nil {
-		log.Printf("error parsing bool %v - %v\n", v, err)
-		v = false
-	}
-
-	return v
-}
-
-func parseFile(config io.Reader) (ConfigMap, error) {
+func ConfigureWithDefaults(filename string, defaultConf ConfigMap) (ConfigMap, error) {
 	var err error
-	parsedMap := make(ConfigMap)
 
-	scanner := bufio.NewScanner(config)
-	for scanner.Scan() {
-		line := scanner.Text()
-		trimmed := strings.TrimSpace(line)
-		if len(trimmed) == 0 {
-			// ignore empty lines
-			continue
-		}
-
-		if trimmed[0] == '#' {
-			// ignore comments
-			continue
-		}
-
-		split := strings.Split(trimmed, "=")
-		if len(split) != 2 {
-			return nil, fmt.Errorf("failed to parse config line: %v", trimmed)
-		}
-
-		key := trimToken(split[0])
-		value := trimToken(split[1])
-
-		parsedMap[key] = value
-	}
-
-	if err = scanner.Err(); err != nil {
+	_, err = os.Stat(filename)
+	if os.IsNotExist(err) {
+		// Config file does not exist, return a default configMap
+		return defaultConf, nil
+	} else if err != nil {
 		return nil, err
 	}
 
-	return parsedMap, nil
-}
-
-func trimToken(value string) string {
-	// Trim off whitespace
-	v := strings.TrimSpace(value)
-
-	// Trim off any surrounding quotes, everything is a string anyway
-	v = strings.TrimPrefix(v, "\"")
-	v = strings.TrimSuffix(v, "\"")
-
-	return v
+	return Configure(filename)
 }

gosimpleconf_test.go

@@ -1,150 +1,40 @@
 package gosimpleconf
 
-import (
-	"flag"
-	"strings"
-	"testing"
-)
+import "testing"
 
-func TestParseWithValidConfig(t *testing.T) {
-	var err error
-	configFileStr := `
-# Some config file
+func TestConfigureWithDefaults(t *testing.T) {
+	defaultMap := ConfigMap{
+		"some": "thing",
+		"cool": "1337",
+	}
 
-foo=bar
-asdf = 1234
+	filename := "idontexist_123456789"
 
-   # Things
-wat.wat= thing
-foo.wat =stuff
-
-immaempty=
-
-technically valid = haha hmm...
-
-#Done
-`
-	configFile := strings.NewReader(configFileStr)
-
-	expectedMap := make(ConfigMap)
-	expectedMap["foo"] = "bar"
-	expectedMap["asdf"] = "1234"
-	expectedMap["wat.wat"] = "thing"
-	expectedMap["foo.wat"] = "stuff"
-	expectedMap["immaempty"] = ""
-	expectedMap["technically valid"] = "haha hmm..."
-
-	parsedMap, err := parseFile(configFile)
+	conf, err := ConfigureWithDefaults(filename, defaultMap)
 	if err != nil {
-		t.Errorf("failed while parsing the file")
+		t.Errorf("unexpected error: %v", err)
 	}
 
-	validateMap(t, parsedMap, expectedMap)
+	validateMap(t, conf, defaultMap)
 }
 
-func TestParseWithExtraEquals(t *testing.T) {
-	var err error
-	configFileStr := `
-foo=bar=true
-`
-	configFile := strings.NewReader(configFileStr)
-
-	_, err = parseFile(configFile)
-	if err == nil {
-		t.Errorf("parse did not thrown an error when it was supposed to")
+func TestConfigure(t *testing.T) {
+	filename := "test.conf"
+	expectedMap := ConfigMap{
+		"url":               "www.wisellama.rocks",
+		"number_of_widgets": "1337",
+		"pi":                "3.141592653589793238462643383",
+		"environment":       "production",
+		"name":              "Dude guy",
+		"description":       "Just some dude it was",
+		"base64_tacos":      "dGFjb3M=",
+		"a":                 "b=c",
 	}
-}
 
-func TestParseWithNoEquals(t *testing.T) {
-	var err error
-	configFileStr := `
-Something here with no equals to split on
-`
-	configFile := strings.NewReader(configFileStr)
-
-	_, err = parseFile(configFile)
-	if err == nil {
-		t.Errorf("parse did not thrown an error when it was supposed to")
-	}
-}
-
-func TestFlagOverrides(t *testing.T) {
-	var err error
-	configFileStr := `
-foo=bar
-asdf = 1234
-foo.wat =stuff
-immaempty=
-`
-	configFile := strings.NewReader(configFileStr)
-
-	expectedMap := make(ConfigMap)
-	expectedMap["foo"] = "bar"
-	expectedMap["asdf"] = "1234"
-	// expect to override the 'foo.wat' value with a cli flag
-	expectedMap["foo.wat"] = "iwasoverridden"
-	expectedMap["immaempty"] = ""
-
-	configMap, err := parseFile(configFile)
+	conf, err := Configure(filename)
 	if err != nil {
-		t.Errorf("failed while parsing the file")
+		t.Errorf("unexpected error: %v", err)
 	}
 
-	flagMap := SetupFlagOverrides(configMap)
-
-	err = flag.Set("foo.wat", "iwasoverridden")
-	if err != nil {
-		t.Errorf("failed to set cli flag override")
-	}
-
-	configMap = ParseFlags(configMap, flagMap)
-
-	validateMap(t, configMap, expectedMap)
-}
-
-func TestParseWithExtraQuotes(t *testing.T) {
-	var err error
-	configFileStr := `
-	some.name = "This is in quotes"
-	extra.quotes = ""This will keep the quotes""
-	internal.quotes = "Some "thing" is here"
-	"This should work too" = shrug I guess
-	`
-
-	configFile := strings.NewReader(configFileStr)
-
-	expectedMap := make(ConfigMap)
-	expectedMap["some.name"] = "This is in quotes"
-	expectedMap["extra.quotes"] = "\"This will keep the quotes\""
-	expectedMap["internal.quotes"] = "Some \"thing\" is here"
-	expectedMap["This should work too"] = "shrug I guess"
-
-	configMap, err := parseFile(configFile)
-	if err != nil {
-		t.Errorf("failed while parsing the file")
-	}
-
-	validateMap(t, configMap, expectedMap)
-}
-
-func validateMap(t *testing.T, given map[string]string, expected map[string]string) {
-	if given == nil {
-		t.Errorf("given map was nil")
-	}
-
-	if expected == nil {
-		t.Errorf("expected map was nil")
-	}
-
-	expectedLen := len(expected)
-	givenLen := len(given)
-	if expectedLen != givenLen {
-		t.Errorf("size mismatch on maps - expected %v, given %v", expectedLen, givenLen)
-	}
-
-	for k, v := range expected {
-		if v != given[k] {
-			t.Errorf("incorrect value for key %v - expected %v, given %v", k, expected[k], given[k])
-		}
-	}
+	validateMap(t, conf, expectedMap)
 }

test.conf

@@ -0,0 +1,13 @@
+url = www.wisellama.rocks
+number_of_widgets = 1337
+pi = 3.141592653589793238462643383
+environment = production
+
+# Quotes are optional
+name = Dude guy
+description = "Just some dude it was"
+
+# Additional equals are just part of the value
+base64_tacos = dGFjb3M=
+a=b=c
+# key: 'a', value: 'b=c'

test_helper.go

@@ -0,0 +1,25 @@
+package gosimpleconf
+
+import "testing"
+
+func validateMap(t *testing.T, given map[string]string, expected map[string]string) {
+	if given == nil {
+		t.Errorf("given map was nil")
+	}
+
+	if expected == nil {
+		t.Errorf("expected map was nil")
+	}
+
+	expectedLen := len(expected)
+	givenLen := len(given)
+	if expectedLen != givenLen {
+		t.Errorf("size mismatch on maps - expected %v, given %v", expectedLen, givenLen)
+	}
+
+	for k, v := range expected {
+		if v != given[k] {
+			t.Errorf("incorrect value for key %v - expected %v, given %v", k, expected[k], given[k])
+		}
+	}
+}