github.phpd.cn/cilium/cilium@v1.6.12/pkg/aws/metadata/metadata.go (about)

     1  // Copyright 2019 Authors of Cilium
     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 metadata
    16  
    17  import (
    18  	"fmt"
    19  	"io/ioutil"
    20  	"net/http"
    21  )
    22  
    23  func getMetadata(name string) (string, error) {
    24  	resp, err := http.Get("http://169.254.169.254/latest/meta-data/" + name)
    25  	if err != nil {
    26  		return "", fmt.Errorf("unable to retrieve instance-id from metadata server: %s", err)
    27  	}
    28  
    29  	defer resp.Body.Close()
    30  	instanceID, err := ioutil.ReadAll(resp.Body)
    31  	if err != nil {
    32  		return "", fmt.Errorf("unable to read response body: %s", err)
    33  	}
    34  
    35  	return string(instanceID), nil
    36  }
    37  
    38  // GetInstanceMetadata returns the instance ID and type
    39  func GetInstanceMetadata() (instanceID, instanceType, availabilityZone, vpcID string, err error) {
    40  	instanceID, err = getMetadata("instance-id")
    41  	if err != nil {
    42  		return
    43  	}
    44  
    45  	instanceType, err = getMetadata("instance-type")
    46  	if err != nil {
    47  		return
    48  	}
    49  
    50  	eth0MAC, err := getMetadata("mac")
    51  	if err != nil {
    52  		return
    53  	}
    54  
    55  	vpcIDPath := fmt.Sprintf("network/interfaces/macs/%s/vpc-id", eth0MAC)
    56  	vpcID, err = getMetadata(vpcIDPath)
    57  	if err != nil {
    58  		return
    59  	}
    60  
    61  	availabilityZone, err = getMetadata("placement/availability-zone")
    62  	return
    63  }