vitess.io/vitess@v0.16.2/go/vt/vtadmin/http/experimental/tablets.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 experimental
    18  
    19  import (
    20  	"bytes"
    21  	"context"
    22  	"encoding/json"
    23  	"io"
    24  	"net/http"
    25  	"text/template"
    26  
    27  	vtadminhttp "vitess.io/vitess/go/vt/vtadmin/http"
    28  
    29  	vtadminpb "vitess.io/vitess/go/vt/proto/vtadmin"
    30  )
    31  
    32  // TabletDebugVarsPassthrough makes a passthrough request to a tablet's
    33  // /debug/vars route, after looking up the tablet via VTAdmin's GetTablet
    34  // rpc.
    35  func TabletDebugVarsPassthrough(ctx context.Context, r vtadminhttp.Request, api *vtadminhttp.API) *vtadminhttp.JSONResponse {
    36  	vars := r.Vars()
    37  
    38  	alias, err := vars.GetTabletAlias("tablet")
    39  	if err != nil {
    40  		return vtadminhttp.NewJSONResponse(nil, err)
    41  	}
    42  
    43  	tablet, err := api.Server().GetTablet(ctx, &vtadminpb.GetTabletRequest{
    44  		Alias:      alias,
    45  		ClusterIds: r.URL.Query()["cluster"],
    46  	})
    47  
    48  	if err != nil {
    49  		return vtadminhttp.NewJSONResponse(nil, err)
    50  	}
    51  
    52  	debugVars, err := getDebugVars(ctx, api, tablet)
    53  	return vtadminhttp.NewJSONResponse(debugVars, err)
    54  }
    55  
    56  func getDebugVars(ctx context.Context, api *vtadminhttp.API, tablet *vtadminpb.Tablet) (map[string]any, error) {
    57  	tmpl, err := template.New("tablet-fqdn").Parse(api.Options().ExperimentalOptions.TabletURLTmpl)
    58  	if err != nil {
    59  		return nil, err
    60  	}
    61  
    62  	buf := bytes.NewBuffer(nil)
    63  	if err := tmpl.Execute(buf, tablet); err != nil {
    64  		return nil, err
    65  	}
    66  	_, _ = buf.WriteString("/debug/vars")
    67  
    68  	url := buf.String()
    69  	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
    70  	if err != nil {
    71  		return nil, err
    72  	}
    73  
    74  	resp, err := http.DefaultClient.Do(req)
    75  	if err != nil {
    76  		return nil, err
    77  	}
    78  
    79  	defer resp.Body.Close()
    80  
    81  	data, err := io.ReadAll(resp.Body)
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  
    86  	var debugVars map[string]any
    87  	if err := json.Unmarshal(data, &debugVars); err != nil {
    88  		return nil, err
    89  	}
    90  
    91  	return debugVars, nil
    92  }