README
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Package command provides consistency in parsing command line flags, reading config files, and writing logs. This package is intended for launching commands with operations (sub-commands).
Commands take the form:
command [flag ...] <operation> [operation flag ...] [arg ...]
Common Operations
Provides a "help" psuedo-operation, which may be invoked as:
command help # shows general usage
command help <operation> # shows operation-specific usage
Common Flags
Top level flags include "-v" for verbosity, and "-config" to specify the directory where configuration files are found.
Flag Helpers
Flags support provided by the golang standard flags package. The command package defines several types to support more advanced flag features.
See StringSet, BoolMap, and BoolCount.
Log Helpers
Logging API is a simple addition to Go stdlib log package.
The V() helper limits verbosity. For example,
command.V(2).Log("hello world")
will write only if the "-v" flag appears twice (or more) in the command flags.
If command.Error() or command.Errorf() is called, then command.Exit() will terminate with a non-zero status.
Documentation
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Overview ¶
Package command provides consistency in parsing command line flags, reading config files, and writing logs. This package is intended for launching commands with operations (sub-commands).
Commands take the form:
command [flag ...] <operation> [operation flag ...] [arg ...]
Common Operations ¶
Provides a "help" psuedo-operation, which may be invoked as:
command help # shows general usage command help <operation> # shows operation-specific usage
Common Flags ¶
Top level flags include "-v" for verbosity, and "-config" to specify the directory where configuration files are found.
Flag Helpers ¶
Flags support provided by the golang standard flags package. The command package defines several types to support more advanced flag features.
See StringSet, BoolMap, and BoolCount.
Log Helpers ¶
Logging API is a simple addition to Go stdlib log package.
The V() helper limits verbosity. For example,
command.V(2).Log("hello world")
will write only if the "-v" flag appears twice (or more) in the command flags.
If command.Error() or command.Errorf() is called, then command.Exit() will terminate with a non-zero status.
Index ¶
- Constants
- Variables
- func Check(err error)
- func CheckUsage(err error)
- func Checkf(err error, format string, arg ...interface{})
- func ConfigDir() string
- func Error(args ...interface{})
- func Errorf(format string, args ...interface{})
- func Exit()
- func Operate(name string)
- func Parse() error
- func RegisterCommand(name, syntax, description string, option ...option)
- func RegisterOperation(handler func() error, name, syntax, description string)
- func UsageError(err interface{})
- func V(threshold int) verbose
- type BoolCount
- type BoolMap
- type StringSet
Constants ¶
const ( OptionConfig option = "config" OptionProfile option = "profile" OptionVerbose option = "verbose" )
Variables ¶
var (
Command command
)
Functions ¶
func Check ¶
func Check(err error)
Check logs an error and exits with non-zero status, when error is not nil.
func CheckUsage ¶
func CheckUsage(err error)
Helper function exits, after showing usage, if error is not nil.
func Checkf ¶
Checkf exits on non-nil error, logging a formatted message.
func ConfigDir ¶
func ConfigDir() string
ConfigDir provides a reasonable default location where configuration files may be found.
func Error ¶
func Error(args ...interface{})
func Exit ¶
func Exit()
func Parse ¶
func Parse() error
Parse is a wrapper around flag.CommandLine.Parse() that is command and operation aware. It strives to parse flags that appear either before or after the opeeration name. It supports a pseudo-operation "help" which behaves as if the "-h" flag is present.
func RegisterCommand ¶
func RegisterCommand(name, syntax, description string, option ...option)
Inject details about the current command.
func RegisterOperation ¶
Types ¶
type BoolCount ¶
type BoolCount int
A flag of type BoolCount can be repeated on the command line. For example: "command -v -v -v" gives the flag value 3.
type BoolMap ¶
A flag of type BoolMap can be repeated on the command line. For example, "command -user=alice -user=carol" gives the value {"alice": true, "carol": true}
Source Files
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- command.go
- config.go
- flags.go
- log.go
- release.go
- verbose.go