oauth2-proxy/oauth2-proxy

package main

import (
    "fmt"
    "os"
    "runtime"

    "github.com/ghodss/yaml"
    "github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/options"
    "github.com/oauth2-proxy/oauth2-proxy/v7/pkg/logger"
    "github.com/oauth2-proxy/oauth2-proxy/v7/pkg/validation"
    "github.com/spf13/pflag"
)

func main() {
    logger.SetFlags(logger.Lshortfile)

    configFlagSet := pflag.NewFlagSet("oauth2-proxy", pflag.ContinueOnError)

    // Because we parse early to determine alpha vs legacy config, we have to
    // ignore any unknown flags for now
    configFlagSet.ParseErrorsWhitelist.UnknownFlags = true

    config := configFlagSet.String("config", "", "path to config file")
    alphaConfig := configFlagSet.String("alpha-config", "", "path to alpha config file (use at your own risk - the structure in this config file may change between minor releases)")
    convertConfig := configFlagSet.Bool("convert-config-to-alpha", false, "if true, the proxy will load configuration as normal and convert existing configuration to the alpha config structure, and print it to stdout")
    showVersion := configFlagSet.Bool("version", false, "print version string")
    configFlagSet.Parse(os.Args[1:])

    if *showVersion {
        fmt.Printf("oauth2-proxy %s (built with %s)\n", VERSION, runtime.Version())
        return
    }

    if *convertConfig && *alphaConfig != "" {
        logger.Fatal("cannot use alpha-config and convert-config-to-alpha together")
    }

    opts, err := loadConfiguration(*config, *alphaConfig, configFlagSet, os.Args[1:])
    if err != nil {
        logger.Fatalf("ERROR: %v", err)
    }

    if *convertConfig {
        if err := printConvertedConfig(opts); err != nil {
            logger.Fatalf("ERROR: could not convert config: %v", err)
        }
        return
    }

    if err = validation.Validate(opts); err != nil {
        logger.Fatalf("%s", err)
    }

    validator := NewValidator(opts.EmailDomains, opts.AuthenticatedEmailsFile)
    oauthproxy, err := NewOAuthProxy(opts, validator)
    if err != nil {
        logger.Fatalf("ERROR: Failed to initialise OAuth2 Proxy: %v", err)
    }

    if err := oauthproxy.Start(); err != nil {
        logger.Fatalf("ERROR: Failed to start OAuth2 Proxy: %v", err)
    }
}

// loadConfiguration will load in the user's configuration.
// It will either load the alpha configuration (if alphaConfig is given)
// or the legacy configuration.
func loadConfiguration(config, alphaConfig string, extraFlags *pflag.FlagSet, args []string) (*options.Options, error) {
    if alphaConfig != "" {
        logger.Printf("WARNING: You are using alpha configuration. The structure in this configuration file may change without notice. You MUST remove conflicting options from your existing configuration.")
        return loadAlphaOptions(config, alphaConfig, extraFlags, args)
    }
    return loadLegacyOptions(config, extraFlags, args)
}

// loadLegacyOptions loads the old toml options using the legacy flagset
// and legacy options struct.
func loadLegacyOptions(config string, extraFlags *pflag.FlagSet, args []string) (*options.Options, error) {
    optionsFlagSet := options.NewLegacyFlagSet()
    optionsFlagSet.AddFlagSet(extraFlags)
    if err := optionsFlagSet.Parse(args); err != nil {
        return nil, fmt.Errorf("failed to parse flags: %v", err)
    }

    legacyOpts := options.NewLegacyOptions()
    if err := options.Load(config, optionsFlagSet, legacyOpts); err != nil {
        return nil, fmt.Errorf("failed to load config: %v", err)
    }

    opts, err := legacyOpts.ToOptions()
    if err != nil {
        return nil, fmt.Errorf("failed to convert config: %v", err)
    }

    return opts, nil
}

// loadAlphaOptions loads the old style config excluding options converted to
// the new alpha format, then merges the alpha options, loaded from YAML,
// into the core configuration.
func loadAlphaOptions(config, alphaConfig string, extraFlags *pflag.FlagSet, args []string) (*options.Options, error) {
    opts, err := loadOptions(config, extraFlags, args)
    if err != nil {
        return nil, fmt.Errorf("failed to load core options: %v", err)
    }

    alphaOpts := &options.AlphaOptions{}
    if err := options.LoadYAML(alphaConfig, alphaOpts); err != nil {
        return nil, fmt.Errorf("failed to load alpha options: %v", err)
    }

    alphaOpts.MergeInto(opts)
    return opts, nil
}

// loadOptions loads the configuration using the old style format into the
// core options.Options struct.
// This means that none of the options that have been converted to alpha config
// will be loaded using this method.
func loadOptions(config string, extraFlags *pflag.FlagSet, args []string) (*options.Options, error) {
    optionsFlagSet := options.NewFlagSet()
    optionsFlagSet.AddFlagSet(extraFlags)
    if err := optionsFlagSet.Parse(args); err != nil {
        return nil, fmt.Errorf("failed to parse flags: %v", err)
    }

    opts := options.NewOptions()
    if err := options.Load(config, optionsFlagSet, opts); err != nil {
        return nil, fmt.Errorf("failed to load config: %v", err)
    }

    return opts, nil
}

// printConvertedConfig extracts alpha options from the loaded configuration
// and renders these to stdout in YAML format.
func printConvertedConfig(opts *options.Options) error {
    alphaConfig := &options.AlphaOptions{}
    alphaConfig.ExtractFrom(opts)

    data, err := yaml.Marshal(alphaConfig)
    if err != nil {
        return fmt.Errorf("unable to marshal config: %v", err)
    }

    if _, err := os.Stdout.Write(data); err != nil {
        return fmt.Errorf("unable to write output: %v", err)
    }

    return nil
}