github.com/m3db/m3@v1.5.0/src/cluster/placementhandler/get.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package placementhandler
    22  
    23  import (
    24  	"errors"
    25  	"fmt"
    26  	"net/http"
    27  	"path"
    28  	"strconv"
    29  	"time"
    30  
    31  	"github.com/m3db/m3/src/cluster/kv"
    32  	"github.com/m3db/m3/src/cluster/placement"
    33  	"github.com/m3db/m3/src/cluster/placementhandler/handleroptions"
    34  	"github.com/m3db/m3/src/query/api/v1/route"
    35  	"github.com/m3db/m3/src/query/generated/proto/admin"
    36  	"github.com/m3db/m3/src/query/util/logging"
    37  	xerrors "github.com/m3db/m3/src/x/errors"
    38  	xhttp "github.com/m3db/m3/src/x/net/http"
    39  
    40  	"go.uber.org/zap"
    41  )
    42  
    43  const (
    44  	// GetHTTPMethod is the HTTP method used with this resource.
    45  	GetHTTPMethod = http.MethodGet
    46  )
    47  
    48  var (
    49  	// M3DBGetURL is the url for the placement get handler (with the GET method)
    50  	// for the M3DB service.
    51  	M3DBGetURL = path.Join(route.Prefix, M3DBServicePlacementPathName)
    52  
    53  	// M3AggGetURL is the url for the placement get handler (with the GET method)
    54  	// for the M3Agg service.
    55  	M3AggGetURL = path.Join(route.Prefix, M3AggServicePlacementPathName)
    56  
    57  	// M3CoordinatorGetURL is the url for the placement get handler (with the GET method)
    58  	// for the M3Coordinator service.
    59  	M3CoordinatorGetURL = path.Join(route.Prefix, M3CoordinatorServicePlacementPathName)
    60  
    61  	errPlacementDoesNotExist = xhttp.NewError(errors.New("placement does not exist"), http.StatusNotFound)
    62  )
    63  
    64  // GetHandler is the handler for placement gets.
    65  type GetHandler Handler
    66  
    67  // NewGetHandler returns a new instance of GetHandler.
    68  func NewGetHandler(opts HandlerOptions) *GetHandler {
    69  	return &GetHandler{HandlerOptions: opts, nowFn: time.Now}
    70  }
    71  
    72  func (h *GetHandler) ServeHTTP(
    73  	service handleroptions.ServiceNameAndDefaults,
    74  	w http.ResponseWriter,
    75  	r *http.Request,
    76  ) {
    77  	var (
    78  		ctx    = r.Context()
    79  		logger = logging.WithContext(ctx, h.instrumentOptions)
    80  	)
    81  
    82  	placement, err := h.Get(service, r)
    83  	if err != nil {
    84  		xhttp.WriteError(w, err)
    85  		return
    86  	}
    87  	if placement == nil {
    88  		xhttp.WriteError(w, errPlacementDoesNotExist)
    89  		return
    90  	}
    91  
    92  	placementProto, err := placement.Proto()
    93  	if err != nil {
    94  		logger.Error("unable to get placement protobuf", zap.Error(err))
    95  		xhttp.WriteError(w, err)
    96  		return
    97  	}
    98  
    99  	resp := &admin.PlacementGetResponse{
   100  		Placement: placementProto,
   101  		Version:   int32(placement.Version()),
   102  	}
   103  
   104  	xhttp.WriteProtoMsgJSONResponse(w, resp, logger)
   105  }
   106  
   107  // Get gets a placement.
   108  func (h *GetHandler) Get(
   109  	svc handleroptions.ServiceNameAndDefaults,
   110  	httpReq *http.Request,
   111  ) (placement placement.Placement, err error) {
   112  	var headers http.Header
   113  	if httpReq != nil {
   114  		headers = httpReq.Header
   115  	}
   116  
   117  	opts := handleroptions.NewServiceOptions(svc, headers, h.m3AggServiceOptions)
   118  	service, err := Service(h.clusterClient, opts,
   119  		Handler(*h).PlacementConfig(), h.nowFn(), nil)
   120  	if err != nil {
   121  		return nil, err
   122  	}
   123  
   124  	if httpReq != nil && httpReq.FormValue("version") != "" {
   125  		version, err := strconv.Atoi(httpReq.FormValue("version"))
   126  		if err != nil {
   127  			return nil, xerrors.NewInvalidParamsError(fmt.Errorf("could not parse version: %v", err))
   128  		}
   129  
   130  		placement, err = service.PlacementForVersion(version)
   131  		if err == kv.ErrNotFound {
   132  			// TODO(rartoul): This should probably be handled at the service
   133  			// level but that would be a large refactor.
   134  			return nil, nil
   135  		}
   136  		if err != nil {
   137  			return nil, err
   138  		}
   139  
   140  		return placement, nil
   141  	}
   142  
   143  	placement, err = service.Placement()
   144  	if err == kv.ErrNotFound {
   145  		// TODO(rartoul): This should probably be handled at the service
   146  		// level but that would be a large refactor.
   147  		return nil, nil
   148  	}
   149  	if err != nil {
   150  		return nil, err
   151  	}
   152  
   153  	return placement, nil
   154  }