Load config from TOML file

cmd/csaf_checker/config.go

@@ -11,28 +11,109 @@ package main
 import (
 	"crypto/tls"
 	"errors"
+	"fmt"
+	"log"
 	"net/http"
+	"os"
+
+	"github.com/BurntSushi/toml"
+	"github.com/csaf-poc/csaf_distribution/v2/util"
+	"github.com/jessevdk/go-flags"
+	"github.com/mitchellh/go-homedir"
 )
 
 type config struct {
-	Output      string      `short:"o" long:"output" description:"File name of the generated report" value-name:"REPORT-FILE"`
-	Format      string      `short:"f" long:"format" choice:"json" choice:"html" description:"Format of report" default:"json"`
-	Insecure    bool        `long:"insecure" description:"Do not check TLS certificates from provider"`
-	ClientCert  *string     `long:"client-cert" description:"TLS client certificate file (PEM encoded data)" value-name:"CERT-FILE"`
-	ClientKey   *string     `long:"client-key" description:"TLS client private key file (PEM encoded data)" value-name:"KEY-FILE"`
-	Version     bool        `long:"version" description:"Display version of the binary"`
-	Verbose     bool        `long:"verbose" short:"v" description:"Verbose output"`
-	Rate        *float64    `long:"rate" short:"r" description:"The average upper limit of https operations per second (defaults to unlimited)"`
-	Years       *uint       `long:"years" short:"y" description:"Number of years to look back from now" value-name:"YEARS"`
-	ExtraHeader http.Header `long:"header" short:"H" description:"One or more extra HTTP header fields"`
+	Output      string      `short:"o" long:"output" description:"File name of the generated report" value-name:"REPORT-FILE" toml:"output"`
+	Format      string      `short:"f" long:"format" choice:"json" choice:"html" description:"Format of report" default:"json" toml:"format"`
+	Insecure    bool        `long:"insecure" description:"Do not check TLS certificates from provider" toml:"insecure"`
+	ClientCert  *string     `long:"client-cert" description:"TLS client certificate file (PEM encoded data)" value-name:"CERT-FILE" toml:"client_cert"`
+	ClientKey   *string     `long:"client-key" description:"TLS client private key file (PEM encoded data)" value-name:"KEY-FILE" toml:"client_key"`
+	Version     bool        `long:"version" description:"Display version of the binary" toml:"-"`
+	Verbose     bool        `long:"verbose" short:"v" description:"Verbose output" toml:"verbose"`
+	Rate        *float64    `long:"rate" short:"r" description:"The average upper limit of https operations per second (defaults to unlimited)" toml:"rate"`
+	Years       *uint       `long:"years" short:"y" description:"Number of years to look back from now" value-name:"YEARS" toml:"years"`
+	ExtraHeader http.Header `long:"header" short:"H" description:"One or more extra HTTP header fields" toml:"header"`
 
-	RemoteValidator        string   `long:"validator" description:"URL to validate documents remotely" value-name:"URL"`
-	RemoteValidatorCache   string   `long:"validatorcache" description:"FILE to cache remote validations" value-name:"FILE"`
-	RemoteValidatorPresets []string `long:"validatorpreset" description:"One or more presets to validate remotely" default:"mandatory"`
+	RemoteValidator        string   `long:"validator" description:"URL to validate documents remotely" value-name:"URL" toml:"validator"`
+	RemoteValidatorCache   string   `long:"validatorcache" description:"FILE to cache remote validations" value-name:"FILE" toml:"validator_cache"`
+	RemoteValidatorPresets []string `long:"validatorpreset" description:"One or more presets to validate remotely" default:"mandatory" toml:"validator_preset"`
+
+	Config *string `short:"c" long:"config" description:"Path to config TOML file" value-name:"TOML-FILE" toml:"-"`
 
 	clientCerts []tls.Certificate
 }
 
+// parseArgsConfig parse the command arguments and loads configuration
+// from a configuration file.
+func parseArgsConfig() ([]string, *config, error) {
+	cfg := &config{
+		RemoteValidatorPresets: []string{"mandatory"},
+	}
+
+	parser := flags.NewParser(cfg, flags.Default)
+	parser.Usage = "[OPTIONS] domain..."
+	args, err := parser.Parse()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if cfg.Version {
+		fmt.Println(util.SemVersion)
+		os.Exit(0)
+	}
+
+	if cfg.Config != nil {
+		path, err := homedir.Expand(*cfg.Config)
+		if err != nil {
+			return nil, nil, err
+		}
+		if err := cfg.load(path); err != nil {
+			return nil, nil, err
+		}
+	} else if path := findConfigFile(); path != "" {
+		if err := cfg.load(path); err != nil {
+			return nil, nil, err
+		}
+	}
+
+	return args, cfg, nil
+}
+
+// configPaths are the potential file locations of the the config file.
+var configPaths = []string{
+	"~/.config/csaf/checker.toml",
+	"~/.csaf_checker.toml",
+	"csaf_checker.toml",
+}
+
+// findConfigFile looks for a file in the pre-defined paths in "configPaths".
+// The returned value will be the name of file if found, otherwise an empty string.
+func findConfigFile() string {
+	for _, f := range configPaths {
+		name, err := homedir.Expand(f)
+		if err != nil {
+			log.Printf("warn: %v\n", err)
+			continue
+		}
+		if _, err := os.Stat(name); err == nil {
+			return name
+		}
+	}
+	return ""
+}
+
+// load loads a configuration from file.
+func (cfg *config) load(path string) error {
+	md, err := toml.DecodeFile(path, &cfg)
+	if err != nil {
+		return err
+	}
+	if undecoded := md.Undecoded(); len(undecoded) != 0 {
+		return fmt.Errorf("could not parse %q from %q", undecoded, path)
+	}
+	return nil
+}
+
 // protectedAccess returns true if we have client certificates or
 // extra http headers configured.
 // This may be a wrong assumption, because the certs are not checked
@@ -41,6 +122,7 @@ func (cfg *config) protectedAccess() bool {
 	return len(cfg.clientCerts) > 0 || len(cfg.ExtraHeader) > 0
 }
 
+// prepare prepares internal state of a loaded configuration.
 func (cfg *config) prepare() error {
 	// Load client certs.
 	switch hasCert, hasKey := cfg.ClientCert != nil, cfg.ClientKey != nil; {
@@ -57,3 +139,13 @@ func (cfg *config) prepare() error {
 	}
 	return nil
 }
+
+// errCheck checks if err is not nil and terminates the program if so.
+func errCheck(err error) {
+	if err != nil {
+		if flags.WroteHelp(err) {
+			os.Exit(0)
+		}
+		log.Fatalf("error: %v\n", err)
+	}
+}