grafana/pkg/tsdb/prometheus/client/cache_test.go
Todd Treece 87e8521591
Prometheus: Implement Streaming JSON Parser (#48477)
use `prometheusStreamingJSONParser` feature toggle to enable
2022-05-13 20:28:54 +02:00

136 lines
3.1 KiB
Go

package client_test
import (
"errors"
"io/ioutil"
"net/http"
"sort"
"strings"
"testing"
"github.com/grafana/grafana/pkg/tsdb/prometheus/client"
"github.com/stretchr/testify/require"
)
func TestCache_GetClient(t *testing.T) {
t.Run("it caches the client for a set of auth headers", func(t *testing.T) {
tc := setupCacheContext()
c, err := tc.providerCache.GetClient(headers)
require.Nil(t, err)
c2, err := tc.providerCache.GetClient(headers)
require.Nil(t, err)
require.Equal(t, c, c2)
require.Equal(t, 1, tc.clientProvider.numCalls)
})
t.Run("it returns different clients when the headers differ", func(t *testing.T) {
tc := setupCacheContext()
h1 := map[string]string{"Authorization": "token", "X-ID-Token": "id-token"}
h2 := map[string]string{"Authorization": "token2", "X-ID-Token": "id-token"}
c, err := tc.providerCache.GetClient(h1)
require.Nil(t, err)
c2, err := tc.providerCache.GetClient(h2)
require.Nil(t, err)
require.NotEqual(t, c, c2)
require.Equal(t, 2, tc.clientProvider.numCalls)
})
t.Run("it returns from the cache when headers are the same", func(t *testing.T) {
tc := setupCacheContext()
h1 := map[string]string{"Authorization": "token", "X-ID-Token": "id-token"}
h2 := map[string]string{"Authorization": "token", "X-ID-Token": "id-token"}
c, err := tc.providerCache.GetClient(h1)
require.Nil(t, err)
c2, err := tc.providerCache.GetClient(h2)
require.Nil(t, err)
require.Equal(t, c, c2)
require.Equal(t, 1, tc.clientProvider.numCalls)
})
t.Run("it doesn't cache anything when an error occurs", func(t *testing.T) {
tc := setupCacheContext()
tc.clientProvider.errors <- errors.New("something bad")
_, err := tc.providerCache.GetClient(headers)
require.EqualError(t, err, "something bad")
c, err := tc.providerCache.GetClient(headers)
require.Nil(t, err)
require.NotNil(t, c)
require.Equal(t, 2, tc.clientProvider.numCalls)
})
}
type cacheTestContext struct {
providerCache *client.ProviderCache
clientProvider *fakeClientProvider
}
func setupCacheContext() *cacheTestContext {
fp := newFakePromClientProvider()
p, err := client.NewProviderCache(fp)
if err != nil {
panic(err)
}
return &cacheTestContext{
providerCache: p,
clientProvider: fp,
}
}
func newFakePromClientProvider() *fakeClientProvider {
return &fakeClientProvider{
errors: make(chan error, 1),
}
}
type fakeClientProvider struct {
headers map[string]string
numCalls int
errors chan error
}
func (p *fakeClientProvider) GetClient(h map[string]string) (*client.Client, error) {
p.headers = h
p.numCalls++
var err error
select {
case err = <-p.errors:
default:
}
var config []string
for _, v := range h {
config = append(config, v)
}
sort.Strings(config) //because map
res := &http.Response{
StatusCode: 200,
Header: http.Header{},
Body: ioutil.NopCloser(strings.NewReader(strings.Join(config, ","))),
}
c := &fakeClient{res: res}
return client.NewClient(c, "GET", "http://localhost:9090/"), err
}
type fakeClient struct {
res *http.Response
}
func (c *fakeClient) Do(req *http.Request) (*http.Response, error) {
return c.res, nil
}