vitess.io/vitess@v0.16.2/go/vt/vtadmin/http/debug/env.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 debug
    18  
    19  import (
    20  	"fmt"
    21  	"net/http"
    22  	"os"
    23  	"sort"
    24  	"strings"
    25  
    26  	"vitess.io/vitess/go/flagutil"
    27  	vtadmindebug "vitess.io/vitess/go/vt/vtadmin/debug"
    28  )
    29  
    30  var (
    31  	// SanitizeEnv is the set of environment variables to sanitize their values
    32  	// in the Env http handler.
    33  	SanitizeEnv flagutil.StringSetFlag
    34  	// OmitEnv is the set of environment variables to omit entirely in the Env
    35  	// http handler.
    36  	OmitEnv flagutil.StringSetFlag
    37  )
    38  
    39  // Env responds with a plaintext listing of key=value pairs of the environment
    40  // variables, sorted by key name.
    41  //
    42  // If a variable appears in OmitEnv, it is excluded entirely. If a variable
    43  // appears in SanitizeEnv, its value is replaced with a sanitized string,
    44  // including if there was no value set in the environment.
    45  func Env(w http.ResponseWriter, r *http.Request) {
    46  	vars := readEnv()
    47  
    48  	msg := &strings.Builder{}
    49  	for i, kv := range vars {
    50  		msg.WriteString(fmt.Sprintf("%s=%s", kv[0], kv[1]))
    51  		if i < len(vars)-1 {
    52  			msg.WriteByte('\n')
    53  		}
    54  	}
    55  
    56  	w.Write([]byte(msg.String()))
    57  }
    58  
    59  func readEnv() [][2]string {
    60  	env := os.Environ()
    61  	vars := make([][2]string, 0, len(env))
    62  
    63  	var key, value string
    64  	for _, ev := range env {
    65  		parts := strings.SplitN(ev, "=", 2)
    66  		switch len(parts) {
    67  		case 0:
    68  			key = ev
    69  		case 1:
    70  			key = parts[0]
    71  		default:
    72  			key = parts[0]
    73  			value = parts[1]
    74  		}
    75  
    76  		if key == "" {
    77  			continue
    78  		}
    79  
    80  		if OmitEnv.ToSet().Has(key) {
    81  			continue
    82  		}
    83  
    84  		if SanitizeEnv.ToSet().Has(key) {
    85  			value = vtadmindebug.SanitizeString(value)
    86  		}
    87  
    88  		vars = append(vars, [2]string{
    89  			key,
    90  			value,
    91  		})
    92  	}
    93  
    94  	// Sort by env var name, ascending.
    95  	sort.SliceStable(vars, func(i, j int) bool {
    96  		left, right := vars[i], vars[j]
    97  		return left[0] < right[0]
    98  	})
    99  
   100  	return vars
   101  }