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Prom read instant handler refactoring #2928

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merged 14 commits into from
Nov 24, 2020
Merged

Prom read instant handler refactoring #2928

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7f94c66
[query] Allow customizing request parsing for /query handler
vpranckaitis Nov 12, 2020
6adad32
fix lint errors
vpranckaitis Nov 12, 2020
c6f43b2
fix another lint error
vpranckaitis Nov 12, 2020
c70d0f5
PR comments
vpranckaitis Nov 13, 2020
1031323
add an interface for hooks
vpranckaitis Nov 16, 2020
4dc973a
Removed read instant handler.
Nov 19, 2020
362a55d
Merge branch 'master' into linasn/read-handler-hooks
Nov 19, 2020
ae5110d
Added some comments.
Nov 19, 2020
b12752a
Uses functional options pattern.
Nov 20, 2020
fbec087
Added comments for exported functions.
Nov 20, 2020
a50265a
Simplified options.
Nov 20, 2020
2314219
Merge branch 'master' into linasn/read-handler-hooks
Nov 24, 2020
7db2913
Got rid of 2 fields in readHandler.
Nov 24, 2020
12e7353
Merge branch 'master' into linasn/read-handler-hooks
robskillington Nov 24, 2020
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6 changes: 3 additions & 3 deletions src/query/api/v1/handler/prom/common.go
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ const (

type errorType string

type queryData struct {
type QueryData struct {
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To me, it doesn't look like queryData needs to be public, at least in the scope of this PR (ditto for Respond and RespondError). Am I missing something?

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Since we can now override default handlers, we might need these for such use-cases.

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I think we should take a bit more care when exposing things. For example, there seems to be a duplicate of this struct in prometheus/response.go, which doesn't surface types from prometheus repository. Maybe we should pick one of those to be public, and not both?

m3/src/query/api/v1/handler/prometheus/response.go

Lines 40 to 69 in 2bcd6fd

type data struct {
// ResultType is the type of Result (matrix, vector, etc.).
ResultType string
// Result contains the query result (concrete type depends on ResultType).
Result result
}
type result interface {
matches(other result) (MatchInformation, error)
}
// MatrixResult contains a list matrixRow.
type MatrixResult struct {
Result []matrixRow `json:"result"`
}
// VectorResult contains a list of vectorItem.
type VectorResult struct {
Result []vectorItem `json:"result"`
}
// ScalarResult is the scalar Value for the response.
type ScalarResult struct {
Result Value `json:"result"`
}
// StringResult is the string Value for the response.
type StringResult struct {
Result Value `json:"result"`
}

Similar question with Respond and RespondError – are these the methods we want to have exposed? Aren't there better candidates?

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response is not made public in this PR so no changes there.
As for Respond and RespondError, I don't think exposing them would make any harm. They do not belong to any class and could be reused by custom handlers without a need to copy the same code (as we are currently doing in our private codebase).

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nit: Need to add comment to exported types // QueryData is ....

ResultType promql.ValueType `json:"resultType"`
Result promql.Value `json:"result"`
}
Expand All @@ -66,7 +66,7 @@ type response struct {
Warnings []string `json:"warnings,omitempty"`
}

func respond(w http.ResponseWriter, data interface{}, warnings promstorage.Warnings) {
func Respond(w http.ResponseWriter, data interface{}, warnings promstorage.Warnings) {
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nit: Need to add comment to exported types // Respond ....

statusMessage := statusSuccess
var warningStrings []string
for _, warning := range warnings {
Expand All @@ -88,7 +88,7 @@ func respond(w http.ResponseWriter, data interface{}, warnings promstorage.Warni
w.Write(b)
}

func respondError(w http.ResponseWriter, err error) {
func RespondError(w http.ResponseWriter, err error) {
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nit: Need to add comment to exported types // RespondError ....

json := jsoniter.ConfigCompatibleWithStandardLibrary
b, marshalErr := json.Marshal(&response{
Status: statusError,
Expand Down
19 changes: 9 additions & 10 deletions src/query/api/v1/handler/prom/prom.go
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,14 @@ func init() {
// Options defines options for PromQL handler.
type Options struct {
PromQLEngine *promql.Engine
instant bool
}
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func (o Options) WithInstant(instant bool) Options {
return Options{
PromQLEngine: o.PromQLEngine,
instant: instant,
}
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@robskillington robskillington Nov 20, 2020 •
edited
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If we're going to do parameterized options for this change, we can simplify this a bit (also note the WithFoo exported symbols need comments):

type opts struct {
  promQLEngine *promql.Engine
  instant      bool
  newQueryFn   NewQueryFn
}

func newDefaultOptions(hOpts options.HandlerOptions) opts {
  return opts{
    promQLEngine: hOpts.PrometheusEngine(),
    instant:      false,
    newQueryFn:   newRangeQueryFn,
  }
}

// Option is a Prometheus handler option.
type Option func(*opts)

// WithEngine sets the PromQL engine.
func WithEngine(promQLEngine *promql.Engine) Option {
  return withEngine(promQLEngine, false)
}

// WithInstantEngine sets the PromQL instant engine.
func WithInstantEngine(promQLEngine *promql.Engine) Option {
  return withEngine(promQLEngine, true)
}

func withEngine(promQLEngine *promql.Engine, instant bool) Option {
  return func(o *opts) error {
    if promQLEngine == nil {
      return errors.New("invalid engine")
    }
    o.instant = instant
    o.promQLEngine = promQLEngine
    o.newQueryFn = newRangeQueryFn
    if instant {
      o.newQueryFn = newInstantQueryFn
    }
    return nil
  }
}

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Looks much simpler to me 👍🏻

}

// NewReadHandler creates a handler to handle PromQL requests.
Expand All @@ -59,17 +67,8 @@ func NewReadHandlerWithHooks(
Storage: hOpts.Storage(),
InstrumentOptions: hOpts.InstrumentOpts(),
})
return newReadHandler(opts, hOpts, hooks, queryable)
}

// NewReadInstantHandler creates a handler to handle PromQL requests.
func NewReadInstantHandler(opts Options, hOpts options.HandlerOptions) http.Handler {
queryable := prometheus.NewPrometheusQueryable(
prometheus.PrometheusOptions{
Storage: hOpts.Storage(),
InstrumentOptions: hOpts.InstrumentOpts(),
})
return newReadInstantHandler(opts, hOpts, queryable)
return newReadHandler(opts, hOpts, hooks, queryable)
}

// ApplyRangeWarnings applies warnings encountered during execution.
Expand Down
100 changes: 70 additions & 30 deletions src/query/api/v1/handler/prom/read.go
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Original file line number Diff line number Diff line change
Expand Up @@ -50,13 +50,47 @@ type ReadHandlerHooks interface {
) (models.RequestParams, error)
}

type NewQueryFn func(
engine *promql.Engine,
queryable promstorage.Queryable,
params models.RequestParams,
) (promql.Query, error)

var (
newRangeQueryFn = func(
engine *promql.Engine,
queryable promstorage.Queryable,
params models.RequestParams,
) (promql.Query, error) {
return engine.NewRangeQuery(
queryable,
params.Query,
params.Start,
params.End,
params.Step)
}

newInstantQueryFn = func(
engine *promql.Engine,
queryable promstorage.Queryable,
params models.RequestParams,
) (promql.Query, error) {
return engine.NewInstantQuery(
queryable,
params.Query,
params.Now)
}
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)

type readHandler struct {
engine *promql.Engine
hooks ReadHandlerHooks
queryable promstorage.Queryable
hOpts options.HandlerOptions
scope tally.Scope
logger *zap.Logger
engine *promql.Engine
hooks ReadHandlerHooks
queryable promstorage.Queryable
newQueryFn NewQueryFn
hOpts options.HandlerOptions
scope tally.Scope
logger *zap.Logger
opts Options
}

func newReadHandler(
Expand All @@ -68,13 +102,21 @@ func newReadHandler(
scope := hOpts.InstrumentOpts().MetricsScope().Tagged(
map[string]string{"handler": "prometheus-read"},
)

newQueryFn := newRangeQueryFn
if opts.instant {
newQueryFn = newInstantQueryFn
}

return &readHandler{
engine: opts.PromQLEngine,
hooks: hooks,
queryable: queryable,
hOpts: hOpts,
scope: scope,
logger: hOpts.InstrumentOpts().Logger(),
engine: opts.PromQLEngine,
hooks: hooks,
queryable: queryable,
newQueryFn: newQueryFn,
hOpts: hOpts,
opts: opts,
scope: scope,
logger: hOpts.InstrumentOpts().Logger(),
}
}

Expand All @@ -83,19 +125,19 @@ func (h *readHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {

fetchOptions, err := h.hOpts.FetchOptionsBuilder().NewFetchOptions(r)
if err != nil {
respondError(w, err)
RespondError(w, err)
return
}

request, err := native.ParseRequest(ctx, r, false, h.hOpts)
request, err := native.ParseRequest(ctx, r, h.opts.instant, h.hOpts)
if err != nil {
respondError(w, err)
RespondError(w, err)
return
}

params, err := h.hooks.OnParsedRequest(ctx, r, request.Params)
if err != nil {
respondError(w, err)
RespondError(w, err)
return
}

Expand All @@ -112,25 +154,22 @@ func (h *readHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
defer cancel()
}

qry, err := h.engine.NewRangeQuery(
h.queryable,
params.Query,
params.Start,
params.End,
params.Step)
qry, err := h.newQueryFn(h.engine, h.queryable, params)
if err != nil {
h.logger.Error("error creating range query",
zap.Error(err), zap.String("query", params.Query))
respondError(w, err)
h.logger.Error("error creating query",
zap.Error(err), zap.String("query", params.Query),
zap.Bool("instant", h.opts.instant))
RespondError(w, err)
return
}
defer qry.Close()

res := qry.Exec(ctx)
if res.Err != nil {
h.logger.Error("error executing range query",
zap.Error(res.Err), zap.String("query", params.Query))
respondError(w, res.Err)
h.logger.Error("error executing query",
zap.Error(res.Err), zap.String("query", params.Query),
zap.Bool("instant", h.opts.instant))
RespondError(w, res.Err)
return
}

Expand All @@ -142,11 +181,12 @@ func (h *readHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
err = ApplyRangeWarnings(query, &resultMetadata)
if err != nil {
h.logger.Warn("error applying range warnings",
zap.Error(err), zap.String("query", query))
zap.Error(err), zap.String("query", query),
zap.Bool("instant", h.opts.instant))
}

handleroptions.AddWarningHeaders(w, resultMetadata)
respond(w, &queryData{
Respond(w, &QueryData{
Result: res.Value,
ResultType: res.Value.Type(),
}, res.Warnings)
Expand Down
138 changes: 0 additions & 138 deletions src/query/api/v1/handler/prom/read_instant.go
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This file was deleted.

4 changes: 3 additions & 1 deletion src/query/api/v1/handler/prom/read_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@ import (
"github.com/m3db/m3/src/query/executor"
xerrors "github.com/m3db/m3/src/x/errors"
"github.com/m3db/m3/src/x/instrument"

"github.com/prometheus/prometheus/pkg/labels"
promstorage "github.com/prometheus/prometheus/storage"
"github.com/stretchr/testify/require"
Expand Down Expand Up @@ -78,7 +79,8 @@ func setupTest(_ *testing.T) testHandlers {
SetTimeoutOpts(timeoutOpts)
queryable := &mockQueryable{}
readHandler := newReadHandler(opts, hOpts, &noopReadHandlerHooks{}, queryable)
readInstantHandler := newReadInstantHandler(opts, hOpts, queryable)
readInstantHandler := newReadHandler(opts.WithInstant(true), hOpts,
&noopReadHandlerHooks{}, queryable)
return testHandlers{
queryable: queryable,
readHandler: readHandler,
Expand Down
2 changes: 1 addition & 1 deletion src/query/api/v1/httpd/handler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -179,7 +179,7 @@ func (h *Handler) RegisterRoutes() error {
PromQLEngine: h.options.PrometheusEngine(),
}
promqlQueryHandler := wrapped(prom.NewReadHandler(opts, nativeSourceOpts))
promqlInstantQueryHandler := wrapped(prom.NewReadInstantHandler(opts, nativeSourceOpts))
promqlInstantQueryHandler := wrapped(prom.NewReadHandler(opts.WithInstant(true), nativeSourceOpts))
nativePromReadHandler := wrapped(native.NewPromReadHandler(nativeSourceOpts))
nativePromReadInstantHandler := wrapped(native.NewPromReadInstantHandler(nativeSourceOpts))

Expand Down