token-counter.go

/*
Copyright 2016 The Kubernetes 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 main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/golang/glog"
	"github.com/google/go-github/github"
	"github.com/spf13/cobra"
	"golang.org/x/oauth2"
)

type tokenCounterFlags struct {
	influx InfluxConfig
	tokens []string
}

func (flags *tokenCounterFlags) AddFlags(cmd *cobra.Command) {
	cmd.Flags().StringSliceVar(&flags.tokens, "token", []string{}, "List of tokens")
	cmd.Flags().AddGoFlagSet(flag.CommandLine)
}

// TokenHandler is refreshing token usage
type TokenHandler struct {
	gClient  *github.Client
	influxdb *InfluxDB
	login    string
}

// GetGithubClient creates a client for each token
func GetGithubClient(token string) *github.Client {
	return github.NewClient(
		oauth2.NewClient(
			oauth2.NoContext,
			oauth2.StaticTokenSource(&oauth2.Token{AccessToken: token}),
		),
	)
}

// GetUsername finds the login for each token
func GetUsername(client *github.Client) (string, error) {
	user, _, err := client.Users.Get(context.Background(), "")
	if err != nil {
		return "", err
	}
	if user.Login == nil {
		return "", errors.New("Users.Get(\"\") returned empty login")
	}

	return *user.Login, nil
}

// CreateTokenHandler parses the token and create a handler
func CreateTokenHandler(tokenStream io.Reader, influxdb *InfluxDB) (*TokenHandler, error) {
	token, err := ioutil.ReadAll(tokenStream)
	if err != nil {
		return nil, err
	}
	client := GetGithubClient(strings.TrimSpace(string(token)))
	login, err := GetUsername(client) // Get user name for token
	if err != nil {
		return nil, err
	}

	return &TokenHandler{
		gClient:  client,
		login:    login,
		influxdb: influxdb,
	}, nil
}

// CreateTokenHandlers goes through the list of token files, and create handlers
func CreateTokenHandlers(tokenFiles []string, influxdb *InfluxDB) ([]TokenHandler, error) {
	tokens := []TokenHandler{}
	for _, tokenFile := range tokenFiles {
		f, err := os.Open(tokenFile)
		if err != nil {
			return nil, fmt.Errorf("Can't open token-file (%s): %s", tokenFile, err)
		}
		token, err := CreateTokenHandler(f, influxdb)
		if err != nil {
			return nil, fmt.Errorf("Failed to create token (%s): %s", tokenFile, err)
		}
		tokens = append(tokens, *token)
	}
	return tokens, nil
}

func (t TokenHandler) getCoreRate() (*github.Rate, error) {
	limits, _, err := t.gClient.RateLimits(context.Background())
	if err != nil {
		return nil, err
	}
	return limits.Core, nil
}

// Process does the main job:
// It tries to get the value of "Remaining" rate just before the token
// gets reset. It does that more and more often (as the reset date gets
// closer) to get the most accurate value.
func (t TokenHandler) Process() {
	lastRate, err := t.getCoreRate()
	if err != nil {
		glog.Fatalf("%s: Couldn't get rate limits: %v", t.login, err)
	}

	for {
		halfPeriod := lastRate.Reset.Time.Sub(time.Now()) / 2
		time.Sleep(halfPeriod)
		newRate, err := t.getCoreRate()
		if err != nil {
			glog.Error("Failed to get CoreRate: ", err)
			continue
		}
		// There is a bug in Github. They seem to reset the Remaining value before resetting the Reset value.
		if !newRate.Reset.Time.Equal(lastRate.Reset.Time) || newRate.Remaining > lastRate.Remaining {
			if err := t.influxdb.Push(
				"github_token_count",
				map[string]string{"login": t.login},
				map[string]interface{}{"value": lastRate.Limit - lastRate.Remaining},
				lastRate.Reset.Time,
			); err != nil {
				glog.Error("Failed to push count:", err)
			}
			// Make sure the timer is properly reset, and we have time anyway
			time.Sleep(30 * time.Minute)
			for {
				newRate, err = t.getCoreRate()
				if err == nil {
					break
				}
				glog.Error("Failed to get CoreRate: ", err)
				time.Sleep(time.Minute)
			}

		}
		lastRate = newRate
	}
}

func runProgram(flags *tokenCounterFlags) error {
	influxdb, err := flags.influx.CreateDatabaseClient()
	if err != nil {
		return err
	}

	tokens, err := CreateTokenHandlers(flags.tokens, influxdb)
	if err != nil {
		return err
	}

	if len(tokens) == 0 {
		glog.Warning("No token given, nothing to do. Leaving...")
		return nil
	}

	for _, token := range tokens {
		go token.Process()
	}

	select {}
}

func main() {
	flags := &tokenCounterFlags{}
	cmd := &cobra.Command{
		Use:   filepath.Base(os.Args[0]),
		Short: "Count usage of github token",
		RunE: func(_ *cobra.Command, _ []string) error {
			return runProgram(flags)
		},
	}
	flags.AddFlags(cmd)
	flags.influx.AddFlags(cmd)

	if err := cmd.Execute(); err != nil {
		glog.Error(err)
	}
}