move the management of the lookback interval to the metadata_service

Signed-off-by: Augustin Husson <husson.augustin@gmail.com>

Author: Nexucis

cmd/promql-langserver/promql-langserver.go

@@ -20,6 +20,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"time"
 
 	kitlog "github.com/go-kit/kit/log"
 	"github.com/prometheus-community/promql-langserver/config"
@@ -41,7 +42,7 @@ func main() {
 	}
 	if conf.RESTAPIPort != 0 {
 		fmt.Fprintln(os.Stderr, "REST API: Listening on port ", conf.RESTAPIPort)
-		prometheusClient, err := promClient.NewClient(conf.PrometheusURL)
+		prometheusClient, err := promClient.NewClient(conf.PrometheusURL, time.Duration(conf.MetadataLookbackInterval))
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -59,7 +60,7 @@ func main() {
 
 		logger = kitlog.NewSyncLogger(logger)
 
-		handler, err := rest.CreateInstHandler(context.Background(), prometheusClient, logger, config.MetadataLookbackInterval)
+		handler, err := rest.CreateInstHandler(context.Background(), prometheusClient, logger)
 		if err != nil {
 			log.Fatal(err)
 		}

config/config.go

@@ -18,11 +18,15 @@ import (
 	"net/url"
 	"os"
 	"strconv"
+	"time"
 
 	"github.com/kelseyhightower/envconfig"
+	"github.com/prometheus/common/model"
 	"gopkg.in/yaml.v3"
 )
 
+const defaultInterval = model.Duration(12 * 3600 * time.Second)
+
 // ReadConfig gets the GlobalConfig from a configFile (that is a path to the file).
 func ReadConfig(configFile string) (*Config, error) {
 	if len(configFile) == 0 {
@@ -70,6 +74,8 @@ type Config struct {
 	LogFormat      LogFormat `yaml:"log_format"`
 	PrometheusURL  string    `yaml:"prometheus_url"`
 	RESTAPIPort    uint64    `yaml:"rest_api_port"`
+	// MetadataLookbackInterval is the time in second used to retrieve label and metrics from Prometheus
+	MetadataLookbackInterval model.Duration `yaml:"metadata_lookback_interval"`
 }
 
 // UnmarshalYAML overrides a function used internally by the yaml.v3 lib.
@@ -94,7 +100,8 @@ func (c *Config) unmarshalENV() error {
 		PrometheusURL  string
 		// the envconfig lib is not able to convert an empty string to the value 0
 		// so we have to convert it manually
-		RESTAPIPort string
+		RESTAPIPort              string
+		MetadataLookbackInterval string
 	}{}
 	if err := envconfig.Process(prefix, conf); err != nil {
 		return err
@@ -106,6 +113,13 @@ func (c *Config) unmarshalENV() error {
 			return parseError
 		}
 	}
+	if len(conf.MetadataLookbackInterval) > 0 {
+		var parseError error
+		c.MetadataLookbackInterval, parseError = model.ParseDuration(conf.MetadataLookbackInterval)
+		if parseError != nil {
+			return parseError
+		}
+	}
 	c.ActivateRPCLog = conf.ActivateRPCLog
 	c.PrometheusURL = conf.PrometheusURL
 	c.LogFormat = LogFormat(conf.LogFormat)
@@ -129,5 +143,9 @@ func (c *Config) Validate() error {
 		c.LogFormat = TextFormat
 	}
 
+	if c.MetadataLookbackInterval <= 0 {
+		c.MetadataLookbackInterval = defaultInterval
+	}
+
 	return nil
 }

config/config_test.go

@@ -30,24 +30,26 @@ func TestUnmarshalENV(t *testing.T) {
 			title:     "empty config",
 			variables: map[string]string{},
 			expected: &Config{
-				ActivateRPCLog: false,
-				LogFormat:      TextFormat,
+				ActivateRPCLog:           false,
+				LogFormat:                TextFormat,
+				MetadataLookbackInterval: defaultInterval,
 			},
 		},
 		{
 			title: "full config",
 			variables: map[string]string{
-				"LANGSERVER_ACTIVATERPCLOG": "true",
-				"LANGSERVER_PROMETHEUSURL":  "http://localhost:9090",
-				"LANGSERVER_RESTAPIPORT":    "8080",
-				"LANGSERVER_LOGFORMAT":      "json",
+				"LANGSERVER_ACTIVATERPCLOG":           "true",
+				"LANGSERVER_PROMETHEUSURL":            "http://localhost:9090",
+				"LANGSERVER_RESTAPIPORT":              "8080",
+				"LANGSERVER_LOGFORMAT":                "json",
 				"LANGSERVER_METADATALOOKBACKINTERVAL": "1w",
 			},
 			expected: &Config{
-				ActivateRPCLog: true,
-				PrometheusURL:  "http://localhost:9090",
-				RESTAPIPort:    8080,
-				LogFormat:      JSONFormat,
+				ActivateRPCLog:           true,
+				PrometheusURL:            "http://localhost:9090",
+				RESTAPIPort:              8080,
+				LogFormat:                JSONFormat,
+				MetadataLookbackInterval: 604800000000000,
 			},
 		},
 	}

langserver/completion.go

@@ -20,7 +20,6 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"time"
 
 	"github.com/pkg/errors"
 
@@ -312,7 +311,7 @@ func (s *server) completeLabel(ctx context.Context, completions *[]protocol.Comp
 	if vs != nil {
 		metricName = vs.Name
 	}
-	allNames, err := s.metadataService.LabelNames(ctx, metricName, time.Now().Add(time.Duration(-1*s.config.MetadataLookbackInterval)), time.Now())
+	allNames, err := s.metadataService.LabelNames(ctx, metricName)
 	if err != nil {
 		// nolint: errcheck
 		s.client.LogMessage(s.lifetime, &protocol.LogMessageParams{
@@ -355,7 +354,7 @@ OUTER:
 
 // nolint: funlen
 func (s *server) completeLabelValue(ctx context.Context, completions *[]protocol.CompletionItem, location *cache.Location, labelName string) error {
-	labelValues, err := s.metadataService.LabelValues(ctx, labelName, time.Now().Add(time.Duration(-1*s.config.MetadataLookbackInterval)), time.Now())
+	labelValues, err := s.metadataService.LabelValues(ctx, labelName)
 	if err != nil {
 		// nolint: errcheck
 		s.client.LogMessage(s.lifetime, &protocol.LogMessageParams{

langserver/config.go

@@ -17,8 +17,10 @@ import (
 	"context"
 	"fmt"
 	"net/url"
+	"time"
 
 	"github.com/prometheus-community/promql-langserver/internal/vendored/go-tools/lsp/protocol"
+	"github.com/prometheus/common/model"
 )
 
 // DidChangeConfiguration is required by the protocol.Server interface.
@@ -67,13 +69,13 @@ func (s *server) DidChangeConfiguration(ctx context.Context, params *protocol.Di
 		})
 	}
 
-/*	if err := s.setMetadataLookbackIntervalFromChangeConfiguration(config); err != nil {
+	if err := s.setMetadataLookbackInterval(config); err != nil {
 		// nolint: errcheck
 		s.client.LogMessage(ctx, &protocol.LogMessageParams{
 			Type:    protocol.Info,
 			Message: err.Error(),
 		})
-	}*/
+	}
 	return nil
 }
 
@@ -101,13 +103,13 @@ func (s *server) connectPrometheus(url string) error {
 	return nil
 }
 
-/*func (s *server) setMetadataLookbackIntervalFromChangeConfiguration(settings map[string]string) error {
+func (s *server) setMetadataLookbackInterval(settings map[string]string) error {
 	if interval, ok := settings["metadataLookbackInterval"]; ok {
 		duration, err := model.ParseDuration(interval)
 		if err != nil {
 			return err
 		}
-		s.config.MetadataLookbackInterval = duration
+		s.metadataService.SetLookbackInterval(time.Duration(duration))
 	}
 	return nil
-}*/
+}

langserver/server.go

@@ -27,6 +27,7 @@ import (
 	"net"
 	"os"
 	"sync"
+	"time"
 
 	"github.com/prometheus-community/promql-langserver/config"
 	promClient "github.com/prometheus-community/promql-langserver/prometheus"
@@ -136,7 +137,7 @@ func ServerFromStream(ctx context.Context, stream jsonrpc2.Stream, conf *config.
 
 	// In order to have an error message in the IDE/editor, we are going to set the prometheusURL in the method server#Initialized.
 	s.prometheusURL = conf.PrometheusURL
-	prometheusClient, err := promClient.NewClient("")
+	prometheusClient, err := promClient.NewClient("", time.Duration(conf.MetadataLookbackInterval))
 	if err != nil {
 		// nolint: errcheck
 		s.client.ShowMessage(s.lifetime, &protocol.ShowMessageParams{

prometheus/compatible.go

@@ -25,6 +25,7 @@ import (
 type compatibleHTTPClient struct {
 	MetadataService
 	prometheusClient v1.API
+	lookbackInterval time.Duration
 }
 
 func (c *compatibleHTTPClient) MetricMetadata(ctx context.Context, metric string) (v1.Metadata, error) {
@@ -46,13 +47,12 @@ func (c *compatibleHTTPClient) AllMetricMetadata(ctx context.Context) (map[strin
 	return c.prometheusClient.Metadata(ctx, "", "")
 }
 
-func (c *compatibleHTTPClient) LabelNames(ctx context.Context, name string,
-	startTime time.Time, endTime time.Time) ([]string, error) {
+func (c *compatibleHTTPClient) LabelNames(ctx context.Context, name string) ([]string, error) {
 	if len(name) == 0 {
-		names, _, err := c.prometheusClient.LabelNames(ctx, startTime, endTime)
+		names, _, err := c.prometheusClient.LabelNames(ctx, time.Now().Add(-1*c.lookbackInterval), time.Now())
 		return names, err
 	}
-	labelNames, _, err := c.prometheusClient.Series(ctx, []string{name}, startTime, endTime)
+	labelNames, _, err := c.prometheusClient.Series(ctx, []string{name}, time.Now().Add(-1*c.lookbackInterval), time.Now())
 	if err != nil {
 		return nil, err
 	}
@@ -70,16 +70,19 @@ func (c *compatibleHTTPClient) LabelNames(ctx context.Context, name string,
 	return result, nil
 }
 
-func (c *compatibleHTTPClient) LabelValues(ctx context.Context, label string,
-	startTime time.Time, endTime time.Time) ([]model.LabelValue, error) {
-	values, _, err := c.prometheusClient.LabelValues(ctx, label, startTime, endTime)
+func (c *compatibleHTTPClient) LabelValues(ctx context.Context, label string) ([]model.LabelValue, error) {
+	values, _, err := c.prometheusClient.LabelValues(ctx, label, time.Now().Add(-1*c.lookbackInterval), time.Now())
 	return values, err
 }
 
 func (c *compatibleHTTPClient) ChangeDataSource(_ string) error {
 	return fmt.Errorf("method not supported")
 }
 
+func (c *compatibleHTTPClient) SetLookbackInterval(interval time.Duration) {
+	c.lookbackInterval = interval
+}
+
 func (c *compatibleHTTPClient) GetURL() string {
 	return ""
 }

prometheus/empty.go

@@ -34,18 +34,22 @@ func (c *emptyHTTPClient) AllMetricMetadata(_ context.Context) (map[string][]v1.
 	return make(map[string][]v1.Metadata), nil
 }
 
-func (c *emptyHTTPClient) LabelNames(_ context.Context, _ string, _ time.Time, _ time.Time) ([]string, error) {
+func (c *emptyHTTPClient) LabelNames(_ context.Context, _ string) ([]string, error) {
 	return []string{}, nil
 }
 
-func (c *emptyHTTPClient) LabelValues(_ context.Context, _ string, _ time.Time, _ time.Time) ([]model.LabelValue, error) {
+func (c *emptyHTTPClient) LabelValues(_ context.Context, _ string) ([]model.LabelValue, error) {
 	return []model.LabelValue{}, nil
 }
 
 func (c *emptyHTTPClient) ChangeDataSource(_ string) error {
 	return fmt.Errorf("method not supported")
 }
 
+func (c *emptyHTTPClient) SetLookbackInterval(_ time.Duration) {
+
+}
+
 func (c *emptyHTTPClient) GetURL() string {
 	return ""
 }

prometheus/metadata_service.go

@@ -92,12 +92,14 @@ type MetadataService interface {
 	AllMetricMetadata(ctx context.Context) (map[string][]v1.Metadata, error)
 	// LabelNames returns all the unique label names present in the block in sorted order.
 	// If a metric is provided, then it will return all unique label names linked to the metric during a predefined period of time
-	LabelNames(ctx context.Context, metricName string, startTime time.Time, endTime time.Time) ([]string, error)
+	LabelNames(ctx context.Context, metricName string) ([]string, error)
 	// LabelValues performs a query for the values of the given label.
-	LabelValues(ctx context.Context, label string, startTime time.Time, endTime time.Time) ([]model.LabelValue, error)
+	LabelValues(ctx context.Context, label string) ([]model.LabelValue, error)
 	// ChangeDataSource is used if the prometheusURL is changing.
 	// The client should re init its own parameter accordingly if necessary
 	ChangeDataSource(prometheusURL string) error
+	// SetLookbackInterval is a method to use to change the interval that then will be used to retrieve data such as label and metrics from prometheus.
+	SetLookbackInterval(interval time.Duration)
 	// GetURL is returning the url used to contact the prometheus server
 	// In case the instance is used directly in Prometheus, it should be the externalURL
 	GetURL() string
@@ -108,15 +110,17 @@ type MetadataService interface {
 // because it will manage which sub instance of the Client to use (like a factory).
 type httpClient struct {
 	MetadataService
-	requestTimeout time.Duration
-	mutex          sync.RWMutex
-	subClient      MetadataService
-	url            string
+	requestTimeout   time.Duration
+	mutex            sync.RWMutex
+	subClient        MetadataService
+	url              string
+	lookbackInterval time.Duration
 }
 
-func NewClient(prometheusURL string) (MetadataService, error) {
+func NewClient(prometheusURL string, lookbackInterval time.Duration) (MetadataService, error) {
 	c := &httpClient{
-		requestTimeout: 30,
+		requestTimeout:   30,
+		lookbackInterval: lookbackInterval,
 	}
 	if err := c.ChangeDataSource(prometheusURL); err != nil {
 		return nil, err
@@ -136,18 +140,16 @@ func (c *httpClient) AllMetricMetadata(ctx context.Context) (map[string][]v1.Met
 	return c.subClient.AllMetricMetadata(ctx)
 }
 
-func (c *httpClient) LabelNames(ctx context.Context, name string,
-	startTime time.Time, endTime time.Time) ([]string, error) {
+func (c *httpClient) LabelNames(ctx context.Context, name string) ([]string, error) {
 	c.mutex.RLock()
 	defer c.mutex.RUnlock()
-	return c.subClient.LabelNames(ctx, name, startTime, endTime)
+	return c.subClient.LabelNames(ctx, name)
 }
 
-func (c *httpClient) LabelValues(ctx context.Context, label string,
-	startTime time.Time, endTime time.Time) ([]model.LabelValue, error) {
+func (c *httpClient) LabelValues(ctx context.Context, label string) ([]model.LabelValue, error) {
 	c.mutex.RLock()
 	defer c.mutex.RUnlock()
-	return c.subClient.LabelValues(ctx, label, startTime, endTime)
+	return c.subClient.LabelValues(ctx, label)
 }
 
 func (c *httpClient) GetURL() string {
@@ -156,6 +158,13 @@ func (c *httpClient) GetURL() string {
 	return c.url
 }
 
+func (c *httpClient) SetLookbackInterval(interval time.Duration) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	c.lookbackInterval = interval
+	c.subClient.SetLookbackInterval(interval)
+}
+
 func (c *httpClient) ChangeDataSource(prometheusURL string) error {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
@@ -192,10 +201,12 @@ func (c *httpClient) ChangeDataSource(prometheusURL string) error {
 	if isCompatible {
 		c.subClient = &compatibleHTTPClient{
 			prometheusClient: v1.NewAPI(prometheusHTTPClient),
+			lookbackInterval: c.lookbackInterval,
 		}
 	} else {
 		c.subClient = &notCompatibleHTTPClient{
 			prometheusClient: v1.NewAPI(prometheusHTTPClient),
+			lookbackInterval: c.lookbackInterval,
 		}
 	}