github.com/mdaxf/iac@v0.0.0-20240519030858-58a061660378/job/admin/command (about)

     1  // Copyright 2020
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  // http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package admin
    16  
    17  import (
    18  	"github.com/pkg/errors"
    19  )
    20  
    21  // Command is an experimental interface
    22  // We try to use this to decouple modules
    23  // All other modules depends on this, and they register the command they support
    24  // We may change the API in the future, so be careful about this.
    25  type Command interface {
    26  	Execute(params ...interface{}) *Result
    27  }
    28  
    29  var CommandNotFound = errors.New("Command not found")
    30  
    31  type Result struct {
    32  	// Status is the same as http.Status
    33  	Status  int
    34  	Error   error
    35  	Content interface{}
    36  }
    37  
    38  func (r *Result) IsSuccess() bool {
    39  	return r.Status >= 200 && r.Status < 300
    40  }
    41  
    42  // CommandRegistry stores all commands
    43  // name => command
    44  type moduleCommands map[string]Command
    45  
    46  // Get returns command with the name
    47  func (m moduleCommands) Get(name string) Command {
    48  	c, ok := m[name]
    49  	if ok {
    50  		return c
    51  	}
    52  	return &doNothingCommand{}
    53  }
    54  
    55  // module name => moduleCommand
    56  type commandRegistry map[string]moduleCommands
    57  
    58  // Get returns module's commands
    59  func (c commandRegistry) Get(moduleName string) moduleCommands {
    60  	if mcs, ok := c[moduleName]; ok {
    61  		return mcs
    62  	}
    63  	res := make(moduleCommands)
    64  	c[moduleName] = res
    65  	return res
    66  }
    67  
    68  var cmdRegistry = make(commandRegistry)
    69  
    70  // RegisterCommand is not thread-safe
    71  // do not use it in concurrent case
    72  func RegisterCommand(module string, commandName string, command Command) {
    73  	cmdRegistry.Get(module)[commandName] = command
    74  }
    75  
    76  func GetCommand(module string, cmdName string) Command {
    77  	return cmdRegistry.Get(module).Get(cmdName)
    78  }
    79  
    80  type doNothingCommand struct{}
    81  
    82  func (d *doNothingCommand) Execute(params ...interface{}) *Result {
    83  	return &Result{
    84  		Status: 404,
    85  		Error:  CommandNotFound,
    86  	}
    87  }