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Merged
SuperQ merged 8 commits into from
Oct 14, 2017
Merged

Add collect[] parameter #699

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f1f6783
Add `collect[]` parameter
siavashs Oct 13, 2017
f012f09
Add TODo comment about staticcheck ignored
siavashs Oct 13, 2017
f192203
Restore promhttp.HandlerOpts
siavashs Oct 13, 2017
d79a168
Log a warning and return HTTP error instead of failing
siavashs Oct 13, 2017
215e9a5
Check collector existence and status, cleanups
siavashs Oct 13, 2017
5194c1b
Fix warnings and error messages
siavashs Oct 13, 2017
c32ec7f
Don't panic, return error if collector registration failed
siavashs Oct 14, 2017
43b0224
Update README
siavashs Oct 14, 2017
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6 changes: 5 additions & 1 deletion Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,10 @@ DOCKER_IMAGE_TAG ?= $(subst /,-,$(shell git rev-parse --abbrev-ref HEAD))
MACH ?= $(shell uname -m)
DOCKERFILE ?= Dockerfile

# TODO: Remove deprecated and problematic InstrumentHandlerFunc usage.
STATICCHECK_IGNORE = \
github.com/prometheus/node_exporter/node_exporter.go:SA1019

ifeq ($(GOHOSTARCH),amd64)
# Only supported on amd64
test-flags := -race
Expand Down Expand Up @@ -99,7 +103,7 @@ vet:

staticcheck: $(STATICCHECK)
@echo ">> running staticcheck"
@$(STATICCHECK) $(pkgs)
@$(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" $(pkgs)
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@grobie grobie Oct 13, 2017

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Please don't introduce staticcheck violations.

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@siavashs siavashs Oct 13, 2017

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This was discussed on IRC with @beorn7 and @SuperQ
Without this we will get:

node_exporter.go:86:32: prometheus.InstrumentHandlerFunc is deprecated: InstrumentHandlerFunc is deprecated for the same reasons as InstrumentHandler is. Use the tooling provided in package promhttp instead.  (SA1019)

Another solution is to use prometheus@v0.8.0 instead of v0.9.0-pre1

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@grobie grobie Oct 13, 2017

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Ok. Please add a comment mentioning InstrumentHandlerFunc and when that ignoring can be removed again.

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@SuperQ SuperQ Oct 13, 2017

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Apparently this will also warn in client_golang v0.8.0 as well. :(


build: $(PROMU)
@echo ">> building binaries"
Expand Down
33 changes: 33 additions & 0 deletions README.md
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Expand Up @@ -107,6 +107,39 @@ echo 'role{role="application_server"} 1' > /path/to/directory/role.prom.$$
mv /path/to/directory/role.prom.$$ /path/to/directory/role.prom
```

### Filtering enabled collectors

The node_exporter will expose all metrics from enabled collectors by default, but it can be passed an optional list of collectors to filter metrics. The `collect[]` parameter accepts values matching enabled collector names.

This can be useful for specifying different scrape intervals for different collectors in Prometheus:

```yaml
scrape_configs:
- job_name: 'node resources'
scrape_interval: 15s
static_configs:
- targets:
- '192.168.1.2:9100'
params:
collect[]:
- cpu
- meminfo
- diskstats
- netdev
- netstat

- job_name: 'node storage'
scrape_interval: 1m
static_configs:
- targets:
- '192.168.1.2:9100'
params:
collect[]:
- filefd
- filesystem
- xfs
```

## Building and running

Prerequisites:
Expand Down
17 changes: 15 additions & 2 deletions collector/collector.go
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Expand Up @@ -80,15 +80,28 @@ type nodeCollector struct {
}

// NewNodeCollector creates a new NodeCollector
func NewNodeCollector() (*nodeCollector, error) {
func NewNodeCollector(filters ...string) (*nodeCollector, error) {
f := make(map[string]bool)
for _, filter := range filters {
enabled, exist := collectorState[filter]
if !exist {
return nil, fmt.Errorf("missing collector: %s", filter)
}
if !*enabled {
return nil, fmt.Errorf("disabled collector: %s", filter)
}
f[filter] = true
}
collectors := make(map[string]Collector)
for key, enabled := range collectorState {
if *enabled {
collector, err := factories[key]()
if err != nil {
return nil, err
}
collectors[key] = collector
if len(f) == 0 || f[key] {
collectors[key] = collector
}
}
}
return &nodeCollector{Collectors: collectors}, nil
Expand Down
49 changes: 38 additions & 11 deletions node_exporter.go
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Expand Up @@ -14,6 +14,7 @@
package main

import (
"fmt"
"net/http"
_ "net/http/pprof"

Expand All @@ -29,6 +30,40 @@ func init() {
prometheus.MustRegister(version.NewCollector("node_exporter"))
}

func handler(w http.ResponseWriter, r *http.Request) {
filters := r.URL.Query()["collect[]"]
log.Debugln("collect query:", filters)

nc, err := collector.NewNodeCollector(filters...)
if err != nil {
log.Warnln("Couldn't create", err)
w.WriteHeader(http.StatusBadRequest)
w.Write([]byte(fmt.Sprintf("Couldn't create %s", err)))
return
}

registry := prometheus.NewRegistry()
err = registry.Register(nc)
if err != nil {
log.Errorln("Couldn't register collector:", err)
w.WriteHeader(http.StatusInternalServerError)
w.Write([]byte(fmt.Sprintf("Couldn't register collector: %s", err)))
return
}

gatherers := prometheus.Gatherers{
prometheus.DefaultGatherer,
registry,
}
// Delegate http serving to Prometheus client library, which will call collector.Collect.
h := promhttp.HandlerFor(gatherers,
promhttp.HandlerOpts{
ErrorLog: log.NewErrorLogger(),
ErrorHandling: promhttp.ContinueOnError,
})
h.ServeHTTP(w, r)
}

func main() {
var (
listenAddress = kingpin.Flag("web.listen-address", "Address on which to expose metrics and web interface.").Default(":9100").String()
Expand All @@ -43,6 +78,7 @@ func main() {
log.Infoln("Starting node_exporter", version.Info())
log.Infoln("Build context", version.BuildContext())

// This instance is only used to check collector creation and logging.
nc, err := collector.NewNodeCollector()
if err != nil {
log.Fatalf("Couldn't create collector: %s", err)
Expand All @@ -52,17 +88,8 @@ func main() {
log.Infof(" - %s", n)
}

if err := prometheus.Register(nc); err != nil {
log.Fatalf("Couldn't register collector: %s", err)
}
handler := promhttp.HandlerFor(prometheus.DefaultGatherer,
promhttp.HandlerOpts{
ErrorLog: log.NewErrorLogger(),
ErrorHandling: promhttp.ContinueOnError,
})

// TODO(ts): Remove deprecated and problematic InstrumentHandler usage.
http.Handle(*metricsPath, prometheus.InstrumentHandler("prometheus", handler))
// TODO(ts): Remove deprecated and problematic InstrumentHandlerFunc usage.
http.HandleFunc(*metricsPath, prometheus.InstrumentHandlerFunc("prometheus", handler))
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(`<html>
<head><title>Node Exporter</title></head>
Expand Down