configuration parser, project structure

.gitignore

@@ -0,0 +1,48 @@
+### Go template
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+### Go.AllowList template
+# Allowlisting gitignore template for GO projects prevents us
+# from adding various unwanted local files, such as generated
+# files, developer configurations or IDE-specific files etc.
+#
+# Recommended: Go.AllowList.gitignore
+
+# Ignore everything
+*
+
+# But not these files...
+!/.gitignore
+
+!*.go
+!go.sum
+!go.mod
+
+!README.md
+!LICENSE
+
+# !Makefile
+
+# ...even if they are in subdirectories
+!*/
+

README.md

@@ -0,0 +1,26 @@
+### Functional Requirements
+
+1. Fetch IP address from multiple sources (can be chosen by the user);
+2. Scripts can be either Python or Bash.
+3. App should expose an API for the changes and checks;
+4. App should have extensive logging;
+5. App should be able to notify users by email;
+6. App configuration should be done via a YAML file.
+
+### User Requirements
+
+1. User can chose ways to be notified if a change happens;
+2. User can define the delta between checks;
+3. User can specify a script to run if the address has, or not changed;
+4. User can choose to check IPv6, IPv4 or both ips.
+
+### Configuration
+
+1. url only needs v4 or v6, or both to be specified
+2. url must be a valid address
+3. response_type is mandatory
+4. response_type can be json | text 
+5. field is mandatory when response_type is json
+6. field must be present in the response from the api and represents the ip field
+7. default source is always the first, the others are used as fallbac1. 
+8. timeout is specified in seconds 

cmd/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"github.com/gweebg/ipwatcher/internal/config"
+	"log"
+)
+
+func main() {
+
+	config.Init()
+
+	v4 := "v4"
+	v6 := "v6"
+	f := "field"
+
+	s := config.Source{
+		Name: "mock",
+		Url: config.SourceUrl{
+			V4: &v4,
+			V6: &v6,
+		},
+		Type:  "json",
+		Field: &f,
+	}
+	err := config.AddSource(s)
+
+	if err != nil {
+
+		log.Print(err.Error())
+	} else {
+		log.Println("good")
+	}
+}

go.mod

@@ -0,0 +1,27 @@
+module github.com/gweebg/ipwatcher
+
+go 1.21.1
+
+require github.com/spf13/viper v1.18.2
+
+require (
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
+	github.com/magiconair/properties v1.8.7 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
+	github.com/pelletier/go-toml/v2 v2.1.0 // indirect
+	github.com/sagikazarmark/locafero v0.4.0 // indirect
+	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
+	github.com/sourcegraph/conc v0.3.0 // indirect
+	github.com/spf13/afero v1.11.0 // indirect
+	github.com/spf13/cast v1.6.0 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/subosito/gotenv v1.6.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.9.0 // indirect
+	golang.org/x/exp v0.0.0-20230905200255-921286631fa9 // indirect
+	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,52 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
+github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
+github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
+github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
+github.com/magiconair/properties v1.8.7 h1:IeQXZAiQcpL9mgcAe1Nu6cX9LLw6ExEHKjN0VQdvPDY=
+github.com/magiconair/properties v1.8.7/go.mod h1:Dhd985XPs7jluiymwWYZ0G4Z61jb3vdS329zhj2hYo0=
+github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
+github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/pelletier/go-toml/v2 v2.1.0 h1:FnwAJ4oYMvbT/34k9zzHuZNrhlz48GB3/s6at6/MHO4=
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+github.com/sagikazarmark/locafero v0.4.0 h1:HApY1R9zGo4DBgr7dqsTH/JJxLTTsOt7u6keLGt6kNQ=
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+github.com/sagikazarmark/slog-shim v0.1.0 h1:diDBnUNK9N/354PgrxMywXnAwEr1QZcOr6gto+ugjYE=
+github.com/sagikazarmark/slog-shim v0.1.0/go.mod h1:SrcSrq8aKtyuqEI1uvTDTK1arOWRIczQRv+GVI1AkeQ=
+github.com/sourcegraph/conc v0.3.0 h1:OQTbbt6P72L20UqAkXXuLOj79LfEanQ+YQFNpLA9ySo=
+github.com/sourcegraph/conc v0.3.0/go.mod h1:Sdozi7LEKbFPqYX2/J+iBAM6HpqSLTASQIKqDmF7Mt0=
+github.com/spf13/afero v1.11.0 h1:WJQKhtpdm3v2IzqG8VMqrr6Rf3UYpEF239Jy9wNepM8=
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+github.com/spf13/cast v1.6.0 h1:GEiTHELF+vaR5dhz3VqZfFSzZjYbgeKDpBxQVS4GYJ0=
+github.com/spf13/cast v1.6.0/go.mod h1:ancEpBxwJDODSW/UG4rDrAqiKolqNNh2DX3mk86cAdo=
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internal/config/config.go

@@ -0,0 +1,97 @@
+package config
+
+import (
+	"errors"
+	"github.com/gweebg/ipwatcher/internal/utils"
+	"github.com/spf13/viper"
+)
+
+var config *viper.Viper
+
+type SourceUrl struct {
+	V4 *string `mapstructure:"v4"`
+	V6 *string `mapstructure:"v6"`
+}
+
+type Source struct {
+	Name  string    `mapstructure:"name"`
+	Url   SourceUrl `mapstructure:"url"`
+	Type  string    `mapstructure:"type"`
+	Field *string   `mapstructure:"field"`
+}
+
+func Init() {
+	// Todo: Maybe hot-reload ?
+	config = viper.New()
+
+	config.SetConfigType("yaml")
+	config.SetConfigName("config")
+	config.AddConfigPath("./")
+	config.AddConfigPath("config/")
+
+	err := config.ReadInConfig()
+	utils.Check(err, "")
+
+	err = validateSources()
+	utils.Check(err, "")
+
+}
+
+func GetSources() ([]Source, error) {
+
+	var sources []Source
+
+	if config == nil {
+		return nil, errors.New("the 'sources' field can only be acquired after config initialization")
+	}
+
+	err := config.UnmarshalKey("sources", &sources)
+	if err != nil {
+		return nil, err
+	}
+
+	return sources, nil
+}
+
+func AddSource(newSource Source) error {
+
+	sources := config.Get("sources").([]interface{})
+	sources = append(sources, newSource)
+
+	config.Set("sources", sources)
+	if err := config.WriteConfig(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func GetConfig() *viper.Viper {
+	return config
+}
+
+func validateSources() error {
+
+	sources, err := GetSources()
+	if err != nil {
+		return err
+	}
+
+	for _, source := range sources {
+
+		if !(source.Url.V4 != nil || source.Url.V6 != nil) {
+			return errors.New("the 'url' field must have at 'v4' or 'v6' or both specified")
+		}
+
+		if source.Type == "json" && source.Field == nil {
+			return errors.New("the 'field' field must be specified if 'response_type' is equal to 'json'")
+		}
+
+		if source.Type != "text" && source.Type != "json" {
+			return errors.New("the field 'response_type' can only be 'text' or 'json'")
+		}
+
+	}
+
+	return nil
+}

internal/fetch/fetch.go

@@ -0,0 +1,29 @@
+package fetch
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+)
+
+func SendHTTPRequest(method, url string, headers map[string]string, payload interface{}) (*http.Response, error) {
+
+	jsonPayload, err := json.Marshal(payload)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(method, url, bytes.NewBuffer(jsonPayload))
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+
+	for key, value := range headers {
+		req.Header.Set(key, value)
+	}
+
+	client := &http.Client{}
+	return client.Do(req)
+}

internal/utils/utils.go

@@ -0,0 +1,13 @@
+package utils
+
+import "log"
+
+func Check(err error, format string, args ...interface{}) {
+	if err != nil {
+		if format != "" {
+			log.Fatalf(format, args...)
+		} else {
+			log.Fatal(err.Error())
+		}
+	}
+}