github.com/rogpeppe/juju@v0.0.0-20140613142852-6337964b789e/state/api/logger/logger.go (about)

     1  // Copyright 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package logger
     5  
     6  import (
     7  	"fmt"
     8  
     9  	"github.com/juju/juju/state/api/base"
    10  	"github.com/juju/juju/state/api/params"
    11  	"github.com/juju/juju/state/api/watcher"
    12  )
    13  
    14  // State provides access to an logger worker's view of the state.
    15  type State struct {
    16  	caller base.Caller
    17  }
    18  
    19  func (st *State) call(method string, params, result interface{}) error {
    20  	return st.caller.Call("Logger", "", method, params, result)
    21  }
    22  
    23  // NewState returns a version of the state that provides functionality
    24  // required by the logger worker.
    25  func NewState(caller base.Caller) *State {
    26  	return &State{caller}
    27  }
    28  
    29  // LoggingConfig returns the loggo configuration string for the agent
    30  // specified by agentTag.
    31  func (st *State) LoggingConfig(agentTag string) (string, error) {
    32  	var results params.StringResults
    33  	args := params.Entities{
    34  		Entities: []params.Entity{{Tag: agentTag}},
    35  	}
    36  	err := st.call("LoggingConfig", args, &results)
    37  	if err != nil {
    38  		// TODO: Not directly tested
    39  		return "", err
    40  	}
    41  	if len(results.Results) != 1 {
    42  		// TODO: Not directly tested
    43  		return "", fmt.Errorf("expected 1 result, got %d", len(results.Results))
    44  	}
    45  	result := results.Results[0]
    46  	if err := result.Error; err != nil {
    47  		return "", err
    48  	}
    49  	return result.Result, nil
    50  }
    51  
    52  // WatchLoggingConfig returns a notify watcher that looks for changes in the
    53  // logging-config for the agent specifed by agentTag.
    54  func (st *State) WatchLoggingConfig(agentTag string) (watcher.NotifyWatcher, error) {
    55  	var results params.NotifyWatchResults
    56  	args := params.Entities{
    57  		Entities: []params.Entity{{Tag: agentTag}},
    58  	}
    59  	err := st.call("WatchLoggingConfig", args, &results)
    60  	if err != nil {
    61  		// TODO: Not directly tested
    62  		return nil, err
    63  	}
    64  	if len(results.Results) != 1 {
    65  		// TODO: Not directly tested
    66  		return nil, fmt.Errorf("expected 1 result, got %d", len(results.Results))
    67  	}
    68  	result := results.Results[0]
    69  	if result.Error != nil {
    70  		//  TODO: Not directly tested
    71  		return nil, result.Error
    72  	}
    73  	w := watcher.NewNotifyWatcher(st.caller, result)
    74  	return w, nil
    75  }