github.com/shashidharatd/test-infra@v0.0.0-20171006011030-71304e1ca560/prow/config/agent.go (about)

     1  /*
     2  Copyright 2017 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package config
    18  
    19  import (
    20  	"sync"
    21  	"time"
    22  
    23  	"github.com/sirupsen/logrus"
    24  )
    25  
    26  // Agent watches a path and automatically loads the config stored
    27  // therein.
    28  type Agent struct {
    29  	sync.Mutex
    30  	c *Config
    31  }
    32  
    33  // Start will begin polling the config file at the path. If the first load
    34  // fails, Start with return the error and abort. Future load failures will log
    35  // the failure message but continue attempting to load.
    36  func (ca *Agent) Start(path string) error {
    37  	c, err := Load(path)
    38  	if err != nil {
    39  		return err
    40  	}
    41  	ca.c = c
    42  	go func() {
    43  		for range time.Tick(1 * time.Minute) {
    44  			if c, err := Load(path); err != nil {
    45  				logrus.WithField("path", path).WithError(err).Error("Error loading config.")
    46  			} else {
    47  				ca.Lock()
    48  				ca.c = c
    49  				ca.Unlock()
    50  			}
    51  		}
    52  	}()
    53  	return nil
    54  }
    55  
    56  // Config returns the latest config. Do not modify the config.
    57  func (ca *Agent) Config() *Config {
    58  	ca.Lock()
    59  	defer ca.Unlock()
    60  	return ca.c
    61  }
    62  
    63  // Set sets the config. Useful for testing.
    64  func (ca *Agent) Set(c *Config) {
    65  	ca.Lock()
    66  	defer ca.Unlock()
    67  	ca.c = c
    68  }