Move packages to proejct/pkg to follow go project folder structure convention (#1190)

pkg/canaryconfigmgr/prometheusClient.go

@@ -0,0 +1,158 @@
+/*
+Copyright 2016 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package canaryconfigmgr
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/pkg/errors"
+	promClient "github.com/prometheus/client_golang/api/prometheus"
+	"github.com/prometheus/common/model"
+	"go.uber.org/zap"
+	"golang.org/x/net/context"
+)
+
+type PrometheusApiClient struct {
+	logger *zap.Logger
+	client promClient.QueryAPI
+}
+
+func MakePrometheusClient(logger *zap.Logger, prometheusSvc string) (*PrometheusApiClient, error) {
+	promApiConfig := promClient.Config{
+		Address: prometheusSvc,
+	}
+
+	promApiClient, err := promClient.New(promApiConfig)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error creating prometheus api client for svc: %s", prometheusSvc)
+	}
+
+	apiQueryClient := promClient.NewQueryAPI(promApiClient)
+
+	return &PrometheusApiClient{
+		logger: logger.Named("prometheus_api_client"),
+		client: apiQueryClient,
+	}, nil
+}
+
+func (promApiClient *PrometheusApiClient) GetFunctionFailurePercentage(path, method, funcName, funcNs string, window string) (float64, error) {
+	// first get a total count of requests to this url in a time window
+	reqs, err := promApiClient.GetRequestsToFuncInWindow(path, method, funcName, funcNs, window)
+	if err != nil {
+		return 0, err
+	}
+
+	if reqs <= 0 {
+		return -1, fmt.Errorf("no requests to this url %v and method %v in the window: %v", path, method, window)
+	}
+
+	// next, get a total count of errored out requests to this function in the same window
+	failedReqs, err := promApiClient.GetTotalFailedRequestsToFuncInWindow(funcName, funcNs, path, method, window)
+	if err != nil {
+		return 0, err
+	}
+
+	// calculate the failure percentage of the function
+	failurePercentForFunc := (failedReqs / reqs) * 100
+
+	return failurePercentForFunc, nil
+}
+
+func (promApiClient *PrometheusApiClient) GetRequestsToFuncInWindow(path string, method string, funcName string, funcNs string, window string) (float64, error) {
+	queryString := fmt.Sprintf("fission_function_calls_total{path=\"%s\",method=\"%s\",name=\"%s\",namespace=\"%s\"}[%v]", path, method, funcName, funcNs, window)
+
+	reqs, err := promApiClient.executeQuery(queryString)
+	if err != nil {
+		return 0, errors.Wrapf(err, "error executing query: %s", queryString)
+	}
+
+	queryString = fmt.Sprintf("fission_function_calls_total{path=\"%s\",method=\"%s\",name=\"%s\",namespace=\"%s\"} offset %v", path, method, funcName, funcNs, window)
+
+	reqsInPrevWindow, err := promApiClient.executeQuery(queryString)
+	if err != nil {
+		return 0, errors.Wrapf(err, "error executing query: %s", queryString)
+	}
+
+	reqsInCurrentWindow := reqs - reqsInPrevWindow
+	promApiClient.logger.Info("function requests",
+		zap.Float64("requests", reqs),
+		zap.Float64("requests_in_previous_window", reqsInPrevWindow),
+		zap.Float64("requests_in_current_window", reqsInCurrentWindow),
+		zap.String("function", funcName))
+
+	return reqsInCurrentWindow, nil
+}
+
+func (promApiClient *PrometheusApiClient) GetTotalFailedRequestsToFuncInWindow(funcName string, funcNs string, path string, method string, window string) (float64, error) {
+	queryString := fmt.Sprintf("fission_function_errors_total{name=\"%s\",namespace=\"%s\",path=\"%s\", method=\"%s\"}[%v]", funcName, funcNs, path, method, window)
+
+	failedRequests, err := promApiClient.executeQuery(queryString)
+	if err != nil {
+		return 0, errors.Wrapf(err, "error executing query: %s", queryString)
+	}
+
+	queryString = fmt.Sprintf("fission_function_errors_total{name=\"%s\",namespace=\"%s\",path=\"%s\", method=\"%s\"} offset %v", funcName, funcNs, path, method, window)
+
+	failedReqsInPrevWindow, err := promApiClient.executeQuery(queryString)
+	if err != nil {
+		return 0, errors.Wrapf(err, "error executing query: %s", queryString)
+	}
+
+	failedReqsInCurrentWindow := failedRequests - failedReqsInPrevWindow
+	promApiClient.logger.Info("function requests",
+		zap.Float64("failed_requests", failedRequests),
+		zap.Float64("failed_requests_in_previous_window", failedReqsInPrevWindow),
+		zap.Float64("failed_requests_in_current_window", failedReqsInCurrentWindow),
+		zap.String("function", funcName))
+
+	return failedReqsInCurrentWindow, nil
+}
+
+func (promApiClient *PrometheusApiClient) executeQuery(queryString string) (float64, error) {
+	val, err := promApiClient.client.Query(context.Background(), queryString, time.Now())
+	if err != nil {
+		return 0, errors.Wrapf(err, "error querying prometheus")
+	}
+
+	switch {
+	case val.Type() == model.ValScalar:
+		scalarVal := val.(*model.Scalar)
+		return float64(scalarVal.Value), nil
+
+	case val.Type() == model.ValVector:
+		vectorVal := val.(model.Vector)
+		total := float64(0)
+		for _, elem := range vectorVal {
+			total = total + float64(elem.Value)
+		}
+		return total, nil
+
+	case val.Type() == model.ValMatrix:
+		matrixVal := val.(model.Matrix)
+		total := float64(0)
+		for _, elem := range matrixVal {
+			total += float64(elem.Values[len(elem.Values)-1].Value)
+		}
+		return total, nil
+
+	default:
+		promApiClient.logger.Info("return value type of prometheus query was unrecognized",
+			zap.Any("type", val.Type()))
+		return 0, nil
+	}
+}