vitess.io/vitess@v0.16.2/go/vt/vtadmin/credentials/credentials.go (about)

     1  /*
     2  Copyright 2021 The Vitess 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 credentials
    18  
    19  import (
    20  	"bytes"
    21  	"encoding/json"
    22  	"os"
    23  	"text/template"
    24  
    25  	"vitess.io/vitess/go/vt/grpcclient"
    26  )
    27  
    28  // LoadFromTemplate renders a template string into a path, using the data
    29  // provided as the template data. It then loads the contents at the resulting
    30  // path as a JSON file containing a grpcclient.StaticAuthClientCreds, and
    31  // returns both the parsed credentials as well as the concrete path used.
    32  func LoadFromTemplate(tmplStr string, data any) (*grpcclient.StaticAuthClientCreds, string, error) {
    33  	path, err := renderTemplate(tmplStr, data)
    34  	if err != nil {
    35  		return nil, "", err
    36  	}
    37  
    38  	creds, err := loadCredentials(path)
    39  	if err != nil {
    40  		return nil, "", err
    41  	}
    42  
    43  	return creds, path, nil
    44  }
    45  
    46  func renderTemplate(tmplStr string, data any) (string, error) {
    47  	tmpl, err := template.New("").Parse(tmplStr)
    48  	if err != nil {
    49  		return "", err
    50  	}
    51  
    52  	buf := bytes.NewBuffer(nil)
    53  	if err := tmpl.Execute(buf, data); err != nil {
    54  		return "", err
    55  	}
    56  
    57  	return buf.String(), nil
    58  }
    59  
    60  func loadCredentials(path string) (*grpcclient.StaticAuthClientCreds, error) {
    61  	data, err := os.ReadFile(path)
    62  	if err != nil {
    63  		return nil, err
    64  	}
    65  
    66  	var creds grpcclient.StaticAuthClientCreds
    67  	if err := json.Unmarshal(data, &creds); err != nil {
    68  		return nil, err
    69  	}
    70  
    71  	return &creds, nil
    72  }