github.com/aacfactory/fns@v1.2.86-0.20240310083819-80d667fc0a17/clusters/host.go (about)

     1  /*
     2   * Copyright 2023 Wang Min Xiang
     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  
    18  package clusters
    19  
    20  import (
    21  	"github.com/aacfactory/errors"
    22  	"github.com/aacfactory/fns/commons/ipx"
    23  	"os"
    24  )
    25  
    26  type HostRetriever func() (host string, err error)
    27  
    28  func defaultHostRetriever() (host string, err error) {
    29  	ip := ipx.GetGlobalUniCastIpFromHostname()
    30  	if ip == nil {
    31  		err = errors.Warning("fns: get host from hostname failed")
    32  		return
    33  	}
    34  	host = ip.String()
    35  	return
    36  }
    37  
    38  func environmentHostRetriever() (host string, err error) {
    39  	v, has := os.LookupEnv("FNS-HOST")
    40  	if has {
    41  		host = v
    42  		return
    43  	}
    44  	err = errors.Warning("fns: get host from FNS-HOST env failed")
    45  	return
    46  }
    47  
    48  var (
    49  	hostRetrievers = map[string]HostRetriever{
    50  		"default": defaultHostRetriever,
    51  		"env":     environmentHostRetriever,
    52  	}
    53  )
    54  
    55  func RegisterHostRetriever(name string, fn HostRetriever) {
    56  	hostRetrievers[name] = fn
    57  }
    58  
    59  func getHostRetriever(name string) (fn HostRetriever, has bool) {
    60  	fn, has = hostRetrievers[name]
    61  	return
    62  }