Caching: Refactor enterprise query caching middleware to a wire service (#65616)
* define initial service and add to wire * update caching service interface * add skipQueryCache header handler and update metrics query function to use it * add caching service as a dependency to query service * working caching impl * propagate cache status to frontend in response * beginning of improvements suggested by Lean - separate caching logic from query logic. * more changes to simplify query function * Decided to revert renaming of function * Remove error status from cache request * add extra documentation * Move query caching duration metric to query package * add a little bit of documentation * wip: convert resource caching * Change return type of query service QueryData to a QueryDataResponse with Headers * update codeowners * change X-Cache value to const * use resource caching in endpoint handlers * write resource headers to response even if it's not a cache hit * fix panic caused by lack of nil check * update unit test * remove NONE header - shouldn't show up in OSS * Convert everything to use the plugin middleware * revert a few more things * clean up unused vars * start reverting resource caching, start to implement in plugin middleware * revert more, fix typo * Update caching interfaces - resource caching now has a separate cache method * continue wiring up new resource caching conventions - still in progress * add more safety to implementation * remove some unused objects * remove some code that I left in by accident * add some comments, fix codeowners, fix duplicate registration * fix source of panic in resource middleware * Update client decorator test to provide an empty response object * create tests for caching middleware * fix unit test * Update pkg/services/caching/service.go Co-authored-by: Arati R. <33031346+suntala@users.noreply.github.com> * improve error message in error log * quick docs update * Remove use of mockery. Update return signature to return an explicit hit/miss bool * create unit test for empty request context * rename caching metrics to make it clear they pertain to caching * Update pkg/services/pluginsintegration/clientmiddleware/caching_middleware.go Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com> * Add clarifying comments to cache skip middleware func * Add comment pointing to the resource cache update call * fix unit tests (missing dependency) * try to fix mystery syntax error * fix a panic * Caching: Introduce feature toggle to caching service refactor (#66323) * introduce new feature toggle * hide calls to new service behind a feature flag * remove licensing flag from toggle (misunderstood what it was for) * fix unit tests * rerun toggle gen --------- Co-authored-by: Arati R. <33031346+suntala@users.noreply.github.com> Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>
This commit is contained in:
Michael Mandrus
co-authored by
Arati R.
Marcus Efraimsson
Arati R.
Marcus Efraimsson
parent
e78be44e1a
commit
5626461b3c
@@ -0,0 +1,35 @@
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package clientmiddleware
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import (
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"github.com/grafana/grafana/pkg/infra/metrics"
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contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
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"github.com/prometheus/client_golang/prometheus"
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)
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const (
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QueryPubdash = "pubdash"
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QueryDashboard = "dashboard"
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)
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var QueryCachingRequestHistogram = prometheus.NewHistogramVec(prometheus.HistogramOpts{
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Namespace: metrics.ExporterName,
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Subsystem: "caching",
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Name: "query_caching_request_duration_seconds",
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Help: "histogram of grafana query endpoint requests in seconds",
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Buckets: []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25, 50, 100},
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}, []string{"datasource_type", "cache", "query_type"})
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var ResourceCachingRequestHistogram = prometheus.NewHistogramVec(prometheus.HistogramOpts{
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Namespace: metrics.ExporterName,
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Subsystem: "caching",
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Name: "resource_caching_request_duration_seconds",
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Help: "histogram of grafana resource endpoint requests in seconds",
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Buckets: []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25, 50, 100},
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}, []string{"plugin_id", "cache"})
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func getQueryType(req *contextmodel.ReqContext) string {
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if req.IsPublicDashboardView {
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return QueryPubdash
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}
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return QueryDashboard
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}
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@@ -0,0 +1,144 @@
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package clientmiddleware
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import (
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"context"
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"time"
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"github.com/grafana/grafana-plugin-sdk-go/backend"
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"github.com/grafana/grafana/pkg/infra/log"
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"github.com/grafana/grafana/pkg/plugins"
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"github.com/grafana/grafana/pkg/services/caching"
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"github.com/grafana/grafana/pkg/services/contexthandler"
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"github.com/prometheus/client_golang/prometheus"
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)
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// NewCachingMiddleware creates a new plugins.ClientMiddleware that will
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// attempt to read and write query results to the cache
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func NewCachingMiddleware(cachingService caching.CachingService) plugins.ClientMiddleware {
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log := log.New("caching_middleware")
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if err := prometheus.Register(QueryCachingRequestHistogram); err != nil {
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log.Error("error registering prometheus collector 'QueryRequestHistogram'", "error", err)
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}
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if err := prometheus.Register(ResourceCachingRequestHistogram); err != nil {
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log.Error("error registering prometheus collector 'ResourceRequestHistogram'", "error", err)
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}
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return plugins.ClientMiddlewareFunc(func(next plugins.Client) plugins.Client {
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return &CachingMiddleware{
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next: next,
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caching: cachingService,
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log: log,
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}
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})
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}
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type CachingMiddleware struct {
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next plugins.Client
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caching caching.CachingService
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log log.Logger
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}
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// QueryData receives a data request and attempts to access results already stored in the cache for that request.
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// If data is found, it will return it immediately. Otherwise, it will perform the queries as usual, then write the response to the cache.
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// If the cache service is implemented, we capture the request duration as a metric. The service is expected to write any response headers.
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func (m *CachingMiddleware) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
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if req == nil {
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return m.next.QueryData(ctx, req)
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}
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reqCtx := contexthandler.FromContext(ctx)
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if reqCtx == nil {
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return m.next.QueryData(ctx, req)
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}
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// time how long this request takes
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start := time.Now()
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// First look in the query cache if enabled
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hit, cr := m.caching.HandleQueryRequest(ctx, req)
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defer func() {
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// record request duration if caching was used
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if ch := reqCtx.Resp.Header().Get(caching.XCacheHeader); ch != "" {
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QueryCachingRequestHistogram.With(prometheus.Labels{
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"datasource_type": req.PluginContext.DataSourceInstanceSettings.Type,
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"cache": ch,
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"query_type": getQueryType(reqCtx),
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}).Observe(time.Since(start).Seconds())
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}
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}()
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// Cache hit; return the response
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if hit {
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return cr.Response, nil
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}
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// Cache miss; do the actual queries
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resp, err := m.next.QueryData(ctx, req)
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// Update the query cache with the result for this metrics request
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if err == nil && cr.UpdateCacheFn != nil {
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cr.UpdateCacheFn(ctx, resp)
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}
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return resp, err
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}
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// CallResource receives a resource request and attempts to access results already stored in the cache for that request.
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// If data is found, it will return it immediately. Otherwise, it will perform the request as usual. The caller of CallResource is expected to explicitly update the cache with any responses.
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// If the cache service is implemented, we capture the request duration as a metric. The service is expected to write any response headers.
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func (m *CachingMiddleware) CallResource(ctx context.Context, req *backend.CallResourceRequest, sender backend.CallResourceResponseSender) error {
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if req == nil {
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return m.next.CallResource(ctx, req, sender)
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}
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reqCtx := contexthandler.FromContext(ctx)
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if reqCtx == nil {
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return m.next.CallResource(ctx, req, sender)
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}
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// time how long this request takes
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start := time.Now()
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// First look in the resource cache if enabled
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hit, resp := m.caching.HandleResourceRequest(ctx, req)
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defer func() {
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// record request duration if caching was used
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if ch := reqCtx.Resp.Header().Get(caching.XCacheHeader); ch != "" {
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ResourceCachingRequestHistogram.With(prometheus.Labels{
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"plugin_id": req.PluginContext.PluginID,
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"cache": ch,
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}).Observe(time.Since(start).Seconds())
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}
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}()
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// Cache hit; send the response and return
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if hit {
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return sender.Send(resp)
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}
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// Cache miss; do the actual request
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// The call to update the cache happens in /pkg/api/plugin_resource.go in the flushStream() func
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// TODO: Implement updating the cache from this method
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return m.next.CallResource(ctx, req, sender)
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}
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func (m *CachingMiddleware) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
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return m.next.CheckHealth(ctx, req)
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}
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func (m *CachingMiddleware) CollectMetrics(ctx context.Context, req *backend.CollectMetricsRequest) (*backend.CollectMetricsResult, error) {
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return m.next.CollectMetrics(ctx, req)
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}
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func (m *CachingMiddleware) SubscribeStream(ctx context.Context, req *backend.SubscribeStreamRequest) (*backend.SubscribeStreamResponse, error) {
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return m.next.SubscribeStream(ctx, req)
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}
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func (m *CachingMiddleware) PublishStream(ctx context.Context, req *backend.PublishStreamRequest) (*backend.PublishStreamResponse, error) {
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return m.next.PublishStream(ctx, req)
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}
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func (m *CachingMiddleware) RunStream(ctx context.Context, req *backend.RunStreamRequest, sender *backend.StreamSender) error {
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return m.next.RunStream(ctx, req, sender)
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}
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@@ -0,0 +1,225 @@
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package clientmiddleware
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import (
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"context"
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"encoding/json"
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"net/http"
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"testing"
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"github.com/grafana/grafana-plugin-sdk-go/backend"
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"github.com/grafana/grafana/pkg/plugins/manager/client/clienttest"
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"github.com/grafana/grafana/pkg/services/caching"
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"github.com/grafana/grafana/pkg/services/contexthandler"
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"github.com/grafana/grafana/pkg/services/user"
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"github.com/stretchr/testify/assert"
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"github.com/stretchr/testify/require"
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)
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func TestCachingMiddleware(t *testing.T) {
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t.Run("When QueryData is called", func(t *testing.T) {
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req, err := http.NewRequest(http.MethodGet, "/query", nil)
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require.NoError(t, err)
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cs := caching.NewFakeOSSCachingService()
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cdt := clienttest.NewClientDecoratorTest(t,
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clienttest.WithReqContext(req, &user.SignedInUser{}),
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clienttest.WithMiddlewares(NewCachingMiddleware(cs)),
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)
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jsonDataMap := map[string]interface{}{}
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jsonDataBytes, err := json.Marshal(&jsonDataMap)
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require.NoError(t, err)
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pluginCtx := backend.PluginContext{
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DataSourceInstanceSettings: &backend.DataSourceInstanceSettings{
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JSONData: jsonDataBytes,
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},
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}
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// Populated by clienttest.WithReqContext
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reqCtx := contexthandler.FromContext(req.Context())
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require.NotNil(t, reqCtx)
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qdr := &backend.QueryDataRequest{
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PluginContext: pluginCtx,
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}
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// Track whether the update cache fn was called, depending on what the response headers are in the cache request
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var updateCacheCalled bool
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dataResponse := caching.CachedQueryDataResponse{
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Response: &backend.QueryDataResponse{},
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UpdateCacheFn: func(ctx context.Context, qdr *backend.QueryDataResponse) {
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updateCacheCalled = true
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},
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}
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t.Run("If cache returns a hit, no queries are issued", func(t *testing.T) {
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t.Cleanup(func() {
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updateCacheCalled = false
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cs.Reset()
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})
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cs.ReturnHit = true
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cs.ReturnQueryResponse = dataResponse
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resp, err := cdt.Decorator.QueryData(req.Context(), qdr)
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assert.NoError(t, err)
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// Cache service is called once
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cs.AssertCalls(t, "HandleQueryRequest", 1)
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// Equals the mocked response
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assert.NotNil(t, resp)
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assert.Equal(t, dataResponse.Response, resp)
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// Cache was not updated by the middleware
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assert.False(t, updateCacheCalled)
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})
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t.Run("If cache returns a miss, queries are issued and the update cache function is called", func(t *testing.T) {
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t.Cleanup(func() {
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updateCacheCalled = false
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cs.Reset()
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})
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cs.ReturnHit = false
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cs.ReturnQueryResponse = dataResponse
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resp, err := cdt.Decorator.QueryData(req.Context(), qdr)
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assert.NoError(t, err)
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// Cache service is called once
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cs.AssertCalls(t, "HandleQueryRequest", 1)
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// Equals nil (returned by the decorator test)
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assert.Nil(t, resp)
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// Since it was a miss, the middleware called the update func
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assert.True(t, updateCacheCalled)
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})
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})
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t.Run("When CallResource is called", func(t *testing.T) {
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req, err := http.NewRequest(http.MethodGet, "/resource/blah", nil)
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require.NoError(t, err)
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cs := caching.NewFakeOSSCachingService()
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cdt := clienttest.NewClientDecoratorTest(t,
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clienttest.WithReqContext(req, &user.SignedInUser{}),
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clienttest.WithMiddlewares(NewCachingMiddleware(cs)),
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)
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jsonDataMap := map[string]interface{}{}
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jsonDataBytes, err := json.Marshal(&jsonDataMap)
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require.NoError(t, err)
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pluginCtx := backend.PluginContext{
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DataSourceInstanceSettings: &backend.DataSourceInstanceSettings{
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JSONData: jsonDataBytes,
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},
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}
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// Populated by clienttest.WithReqContext
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reqCtx := contexthandler.FromContext(req.Context())
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require.NotNil(t, reqCtx)
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crr := &backend.CallResourceRequest{
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PluginContext: pluginCtx,
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}
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resourceResponse := &backend.CallResourceResponse{
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Status: 200,
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Body: []byte("bogus"),
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}
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var sentResponse *backend.CallResourceResponse
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var storeOneResponseCallResourceSender = callResourceResponseSenderFunc(func(res *backend.CallResourceResponse) error {
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sentResponse = res
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return nil
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})
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t.Run("If cache returns a hit, no resource call is issued", func(t *testing.T) {
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t.Cleanup(func() {
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sentResponse = nil
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cs.Reset()
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})
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cs.ReturnHit = true
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cs.ReturnResourceResponse = resourceResponse
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err := cdt.Decorator.CallResource(req.Context(), crr, storeOneResponseCallResourceSender)
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assert.NoError(t, err)
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// Cache service is called once
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cs.AssertCalls(t, "HandleResourceRequest", 1)
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// Equals the mocked response was sent
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assert.NotNil(t, sentResponse)
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assert.Equal(t, resourceResponse, sentResponse)
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})
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t.Run("If cache returns a miss, resource call is issued", func(t *testing.T) {
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t.Cleanup(func() {
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sentResponse = nil
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cs.Reset()
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})
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cs.ReturnHit = false
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cs.ReturnResourceResponse = resourceResponse
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err := cdt.Decorator.CallResource(req.Context(), crr, storeOneResponseCallResourceSender)
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assert.NoError(t, err)
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// Cache service is called once
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cs.AssertCalls(t, "HandleResourceRequest", 1)
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// Nil response was sent
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assert.Nil(t, sentResponse)
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})
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})
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t.Run("When RequestContext is nil", func(t *testing.T) {
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req, err := http.NewRequest(http.MethodGet, "/doesnt/matter", nil)
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require.NoError(t, err)
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cs := caching.NewFakeOSSCachingService()
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cdt := clienttest.NewClientDecoratorTest(t,
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// Skip the request context in this case
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clienttest.WithMiddlewares(NewCachingMiddleware(cs)),
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)
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reqCtx := contexthandler.FromContext(req.Context())
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require.Nil(t, reqCtx)
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jsonDataMap := map[string]interface{}{}
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jsonDataBytes, err := json.Marshal(&jsonDataMap)
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require.NoError(t, err)
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pluginCtx := backend.PluginContext{
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DataSourceInstanceSettings: &backend.DataSourceInstanceSettings{
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JSONData: jsonDataBytes,
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},
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}
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t.Run("Query caching is skipped", func(t *testing.T) {
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t.Cleanup(func() {
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cs.Reset()
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})
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qdr := &backend.QueryDataRequest{
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PluginContext: pluginCtx,
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}
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resp, err := cdt.Decorator.QueryData(context.Background(), qdr)
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assert.NoError(t, err)
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// Cache service is never called
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cs.AssertCalls(t, "HandleQueryRequest", 0)
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// Equals nil (returned by the decorator test)
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assert.Nil(t, resp)
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})
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t.Run("Resource caching is skipped", func(t *testing.T) {
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t.Cleanup(func() {
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cs.Reset()
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})
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crr := &backend.CallResourceRequest{
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PluginContext: pluginCtx,
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}
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err := cdt.Decorator.CallResource(req.Context(), crr, nopCallResourceSender)
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assert.NoError(t, err)
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// Cache service is never called
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cs.AssertCalls(t, "HandleResourceRequest", 0)
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})
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})
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}
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Reference in New Issue
Block a user