mirror of https://github.com/knative/func.git
90 lines
3.0 KiB
Go
90 lines
3.0 KiB
Go
package cmd
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import (
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"fmt"
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"os"
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"github.com/mitchellh/go-homedir"
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"github.com/ory/viper"
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"github.com/spf13/cobra"
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)
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var (
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config = "~/.faas/config" // Location of the optional config file.
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verbose = false // Enable verbose logging (debug).
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)
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// The root of the command tree defines the command name, descriotion, globally
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// available flags, etc. It has no action of its own, such that running the
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// resultant binary with no arguments prints the help/usage text.
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var root = &cobra.Command{
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Use: "faas",
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Short: "Function as a Service Manager",
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Version: Version,
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SilenceErrors: true, // we explicitly handle errors in Execute()
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SilenceUsage: true, // no usage dump on error
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Long: `Function as a Service Manager
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Create, run and deploy.`,
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}
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// When the code is loaded into memory upon invocation, the cobra/viper packages
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// are invoked to gather system context. This includes reading the configuration
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// file, environment variables, and parsing the command flags.
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func init() {
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// Populate `config` var with the value of --config flag, if provided.
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root.PersistentFlags().StringVar(&config, "config", config, "config file path")
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// Read in the config file specified by `config`, overriding defaults.
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cobra.OnInitialize(readConfig)
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// Populate the `verbose` flag with the value of --verbose, if provided,
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// which thus overrides both the default and the value read in from the
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// config file (i.e. flags always take highest precidence).
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root.PersistentFlags().BoolVarP(&verbose, "verbose", "v", verbose, "print verbose logs")
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viper.BindPFlag("verbose", root.PersistentFlags().Lookup("verbose"))
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// Override the --version template to match the output format from the
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// version subcommand: nothing but the version.
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root.SetVersionTemplate(`{{printf "%s\n" .Version}}`)
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// Prefix all environment variables with "FAAS_" to avoid collisions with other apps.
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viper.SetEnvPrefix("faas")
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}
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// readConfig populates variables (overriding defaults) from the config file
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// and environment variables.
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func readConfig() {
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if config != "" {
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viper.SetConfigFile(config) // Use config file from the flag.
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} else {
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home, err := homedir.Dir() // Find home directory.
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if err != nil {
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fmt.Println(err)
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os.Exit(1)
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}
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viper.AddConfigPath(home) // Search for cconfig in home
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viper.SetConfigName(".faascfg")
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}
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// read in environment variables that match
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viper.AutomaticEnv()
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// If a config file is found, read it in.
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if err := viper.ReadInConfig(); err == nil {
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fmt.Println("Using config file:", viper.ConfigFileUsed())
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}
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}
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// Execute the command tree by executing the root command, which runs
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// according to the context defined by: the optional config file,
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// Environment Variables, command arguments and flags.
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func Execute() {
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// Execute the root of the command tree.
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if err := root.Execute(); err != nil {
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// Errors are printed to STDERR output and the process exits with code of 1.
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fmt.Fprintf(os.Stderr, "Error: %v\n", err)
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os.Exit(1)
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}
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}
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