kraken

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// Copyright (c) 2016-2019 Uber Technologies, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package metrics
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import (
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	"errors"
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	"fmt"
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	"io"
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	"os"
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	"time"
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	"github.com/uber/kraken/utils/log"
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	"github.com/uber-go/tally"
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)
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func init() {
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	register("statsd", newStatsdScope)
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	register("disabled", newDisabledScope)
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	register("m3", newM3Scope)
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}
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var _scopeFactories = make(map[string]scopeFactory)
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type scopeFactory func(config Config, cluster string) (tally.Scope, io.Closer, error)
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func register(name string, f scopeFactory) {
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	if _, ok := _scopeFactories[name]; ok {
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		log.Fatalf("Metrics reporter factory %q is already registered", name)
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	}
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	_scopeFactories[name] = f
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}
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// New creates a new metrics Scope from config. If no backend is configured, metrics
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// are disabled.
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func New(config Config, cluster string) (tally.Scope, io.Closer, error) {
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	if config.Backend == "" {
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		config.Backend = "disabled"
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	}
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	f, ok := _scopeFactories[config.Backend]
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	if !ok || f == nil {
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		return nil, nil, fmt.Errorf("metrics backend %q not registered", config.Backend)
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	}
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	return f(config, cluster)
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}
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// EmitVersion periodically emits the current GIT_DESCRIBE as a metric.
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func EmitVersion(stats tally.Scope) {
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	counter, err := getVersionCounter(stats)
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	if err != nil {
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		log.Warnf("Skipping version emitting: %s", err)
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		return
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	}
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	for {
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		time.Sleep(time.Minute)
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		counter.Inc(1)
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	}
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}
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func getVersionCounter(stats tally.Scope) (tally.Counter, error) {
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	version := os.Getenv("GIT_DESCRIBE")
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	if version == "" {
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		return nil, errors.New("no GIT_DESCRIBE env variable found")
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	}
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	hostname, err := os.Hostname()
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	if err != nil {
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		return nil, fmt.Errorf("hostname: %s", err)
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	}
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	return stats.Tagged(map[string]string{
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		"host":    hostname,
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		"version": version,
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	}).Counter("version"), nil
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}
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