From c497e2f19c05450f25281a80180008387a2878de Mon Sep 17 00:00:00 2001 From: Felix Auringer <48409110+felixauringer@users.noreply.github.com> Date: Fri, 30 Apr 2021 08:53:00 +0200 Subject: [PATCH] Improve configuration with config file This adds explanations to the example config file, renames the file in order to enable yaml syntax highlighting and fixes the parsing of the flag specifying where to find the configuration file. --- .gitignore | 5 ++-- config/config.go | 52 +++++++++++++++++++++++++++----------- configuration.example.yaml | 30 ++++++++++++++++++++++ main.go | 4 ++- 4 files changed, 73 insertions(+), 18 deletions(-) create mode 100644 configuration.example.yaml diff --git a/.gitignore b/.gitignore index 10cfefe..9035ee4 100644 --- a/.gitignore +++ b/.gitignore @@ -1,8 +1,9 @@ # Project binary poseidon +# Configuration file +configuration.yaml + # TLS certificate/key *.crt *.key - -configuration.yaml diff --git a/config/config.go b/config/config.go index 2c4559f..5bb5222 100644 --- a/config/config.go +++ b/config/config.go @@ -2,6 +2,7 @@ package config import ( "crypto/tls" + "errors" "flag" "fmt" "gitlab.hpi.de/codeocean/codemoon/poseidon/logging" @@ -13,6 +14,7 @@ import ( "strings" ) +// Config contains the default configuration of Poseidon. var ( Config = &configuration{ Server: server{ @@ -25,22 +27,25 @@ var ( }, Nomad: nomad{ Address: "", - Token: "", Port: 4646, + Token: "", TLS: false, }, Logger: logger{ Level: "INFO", }, } - log = logging.GetLogger("config") - TLSConfig = &tls.Config{ + configurationFilePath = "./configuration.yaml" + configurationInitialized = false + log = logging.GetLogger("config") + TLSConfig = &tls.Config{ MinVersion: tls.VersionTLS13, CurvePreferences: []tls.CurveID{tls.CurveP521, tls.CurveP384, tls.CurveP256}, PreferServerCipherSuites: true, } ) +// server configures the Poseidon webserver. type server struct { Address string Port int @@ -50,27 +55,39 @@ type server struct { KeyFile string } +// nomad configures the used Nomad cluster. type nomad struct { Address string - Token string Port int + Token string TLS bool } +// logger configures the used logger. type logger struct { Level string } +// configuration contains the complete configuration of Poseidon. type configuration struct { Server server Nomad nomad Logger logger } -func InitConfig() { +// InitConfig merges configuration options from environment variables and +// a configuration file into the default configuration. Calls of InitConfig +// after the first call have no effect and return an error. InitConfig +// should be called directly after starting the program. +func InitConfig() error { + if configurationInitialized { + return errors.New("configuration is already initialized") + } + configurationInitialized = true content := readConfigFile() Config.mergeYaml(content) Config.mergeEnvironmentVariables() + return nil } func (c *configuration) NomadAPIURL() *url.URL { @@ -93,16 +110,21 @@ func parseURL(address string, port int, tls bool) *url.URL { } func readConfigFile() []byte { - var configFilePath string - flag.StringVar(&configFilePath, "config", "./configuration.yaml", "path of the yaml config file") - flag.Parse() - data, err := os.ReadFile(configFilePath) + parseFlags() + data, err := os.ReadFile(configurationFilePath) if err != nil { log.WithError(err).Info("Using default configuration...") } return data } +func parseFlags() { + if flag.Lookup("config") == nil { + flag.StringVar(&configurationFilePath, "config", configurationFilePath, "path of the yaml config file") + } + flag.Parse() +} + func (c *configuration) mergeYaml(content []byte) { if err := yaml.Unmarshal(content, c); err != nil { log.WithError(err).Fatal("Could not parse configuration file") @@ -114,20 +136,20 @@ func (c *configuration) mergeEnvironmentVariables() { } func readFromEnvironment(prefix string, value reflect.Value) { - if !value.CanSet() || !value.CanInterface() { + logEntry := log.WithField("prefix", prefix) + // if value was not derived from a pointer, it is not possible to alter its contents + if !value.CanSet() { + logEntry.Warn("Cannot overwrite struct field that can not be set") return } if value.Kind() != reflect.Struct { content, ok := os.LookupEnv(prefix) - - logEntry := log. - WithField("prefix", prefix). - WithField("content", content) - if !ok { return } + logEntry = logEntry.WithField("content", content) + switch value.Kind() { case reflect.String: value.SetString(content) diff --git a/configuration.example.yaml b/configuration.example.yaml new file mode 100644 index 0000000..3921ade --- /dev/null +++ b/configuration.example.yaml @@ -0,0 +1,30 @@ +# Configuration of the Poseidon webserver +server: + # Address on which the webserver listens + address: 127.0.0.1 + # Port on which the webserver listens + port: 3000 + # If set, this token is required in the X-Poseidon-Token header for each route except /health + token: SECRET + # If set, the API uses TLS for all incoming connections + tls: true + # The path to the certificate file used for TLS + certfile: ./poseidon.crt + # The path to the key file used for TLS + keyfile: ./poseidon.key + +# Configuration of the used Nomad cluster +nomad: + # IP address / domain of the Nomad server + address: 127.0.0.1 + # Port of the Nomad server + port: 4646 + # Authenticate requests to the Nomad server with this token + token: SECRET + # Specifies whether to use TLS when communicating with the Nomad server + tls: false + +# Configuration of the logger +logger: + # Log level that is used after reading the config (INFO until then) + level: DEBUG diff --git a/main.go b/main.go index 9b42130..84ece86 100644 --- a/main.go +++ b/main.go @@ -63,7 +63,9 @@ func shutdownOnOSSignal(server *http.Server) { } func main() { - config.InitConfig() + if err := config.InitConfig(); err != nil { + log.WithError(err).Warn("Could not initialize configuration") + } logging.InitializeLogging(config.Config.Logger.Level) server := initServer() log.WithField("address", server.Addr).Info("Starting server")