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/*
* errors.go - Common errors and error handling
*
* Copyright 2017 Google Inc.
* Author: Joe Richey (joerichey@google.com)
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package cmd
import (
"fmt"
"os"
"github.com/pkg/errors"
)
// Common errors used across tools
var (
ErrUnknownVersion = errors.New("unknown version (missing version tag)")
ErrCanceled = errors.New("operation canceled by user")
ErrMustForce = errors.New("operation must be forced")
)
// Error return codes
var (
FailureCode = 1
UsageFailureCode = 2
)
// UsageError is an error type used to denote that a command was incorrectly
// specified. Returning this type from an Action will cause print the command's
// usage to os.Stdout before exiting with UsageFailureCode.
type UsageError string
func (u UsageError) Error() string { return string(u) }
// CheckExpectedArgs returns a UsageError if the number of arguments in the
// context does not match expectedArgs. If atMost is set, the number of args
// is allowed to be less than expectedArgs.
func CheckExpectedArgs(ctx *Context, expectedArgs int, atMost bool) error {
// Check the number of arguments and build the message.
nArgs := len(ctx.Args)
message := "expected"
if atMost {
if nArgs <= expectedArgs {
return nil
}
message += " at most"
} else {
if nArgs == expectedArgs {
return nil
}
}
// We have the wrong number of arguments
message += fmt.Sprintf(" %s, got %s",
Pluralize(expectedArgs, "argument"),
Pluralize(nArgs, "argument"))
return UsageError(message)
}
// CheckRequiredFlags returns a UsageError if all of the required flags are not
// set. Only StringFlags are currently supported.
func CheckRequiredFlags(flags []*StringFlag) error {
for _, flag := range flags {
if flag.Value == "" {
return UsageError(fmt.Sprintf("required flag %s not set", flag))
}
}
return nil
}
// processError TODO(joerichey)
func (ctx *Context) processError(err error) {
if err == nil {
return
}
fmt.Fprintf(os.Stderr, "%s: %s\n", ctx.FullName(), err)
// Usage Errors should print the usage information
if _, ok := err.(UsageError); ok {
ExecuteTemplate(os.Stderr, TemplateUsage, ctx)
os.Exit(UsageFailureCode)
return
}
// Errors with a help text should print it out.
if helpText := ctx.getHelpText(err); helpText != "" {
fmt.Fprintln(os.Stderr)
fmt.Fprintln(os.Stderr, helpText)
}
os.Exit(FailureCode)
return
}
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