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main.go
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package main
import (
"context"
"database/sql"
"errors"
"flag"
"net/http"
"os"
"strconv"
"strings"
"time"
"github.com/BurntSushi/toml"
_ "github.com/mattn/go-oci8"
"fmt"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
//Required for debugging
//_ "net/http/pprof"
)
var (
// Version will be set at build time.
Version = "0.0.0.dev"
listenAddress = flag.String("web.listen-address", getEnv("LISTEN_ADDRESS", ":9161"), "Address to listen on for web interface and telemetry. (env: LISTEN_ADDRESS)")
metricPath = flag.String("web.telemetry-path", getEnv("TELEMETRY_PATH", "/metrics"), "Path under which to expose metrics. (env: TELEMETRY_PATH)")
landingPage = []byte("<html><head><title>Oracle DB Exporter " + Version + "</title></head><body><h1>Oracle DB Exporter " + Version + "</h1><p><a href='" + *metricPath + "'>Metrics</a></p></body></html>")
defaultFileMetrics = flag.String("default.metrics", getEnv("DEFAULT_METRICS", "default-metrics.toml"), "File with default metrics in a TOML file. (env: DEFAULT_METRICS)")
customMetrics = flag.String("custom.metrics", getEnv("CUSTOM_METRICS", ""), "File that may contain various custom metrics in a TOML file. (env: CUSTOM_METRICS)")
queryTimeout = flag.String("query.timeout", getEnv("QUERY_TIMEOUT", "5"), "Query timeout (in seconds). (env: QUERY_TIMEOUT)")
maxIdleConns = flag.Int("database.maxIdleConns", atoi(getEnv("DATABASE_MAXIDLECONNS", "0")), "Number of maximum idle connections in the connection pool. (env: DATABASE_MAXIDLECONNS)")
maxOpenConns = flag.Int("database.maxOpenConns", atoi(getEnv("DATABASE_MAXOPENCONNS", "10")), "Number of maximum open connections in the connection pool. (env: DATABASE_MAXOPENCONNS)")
)
// Metric name parts.
const (
namespace = "oracledb"
exporter = "exporter"
)
// Metrics object description
type Metric struct {
Context string
Labels []string
MetricsDesc map[string]string
MetricsType map[string]string
FieldToAppend string
Request string
IgnoreZeroResult bool
}
// Used to load multiple metrics from file
type Metrics struct {
Metric []Metric
}
// Metrics to scrap. Use external file (default-metrics.toml and custom if provided)
var (
metricsToScrap Metrics
additionalMetrics Metrics
)
// Exporter collects Oracle DB metrics. It implements prometheus.Collector.
type Exporter struct {
dsn string
duration, error prometheus.Gauge
totalScrapes prometheus.Counter
scrapeErrors *prometheus.CounterVec
up prometheus.Gauge
db *sql.DB
}
// getEnv returns the value of an environment variable, or returns the provided fallback value
func getEnv(key, fallback string) string {
if value, ok := os.LookupEnv(key); ok {
return value
}
return fallback
}
func atoi(stringValue string) int {
intValue, err := strconv.Atoi(stringValue)
if err != nil {
log.Fatal("error while converting to int:", err)
panic(err)
}
return intValue
}
func connect(dsn string) *sql.DB {
log.Debugln("Launching connection: ", dsn)
db, err := sql.Open("oci8", dsn)
if err != nil {
log.Errorln("Error while connecting to", dsn)
panic(err)
}
log.Debugln("set max idle connections to ", *maxIdleConns)
db.SetMaxIdleConns(*maxIdleConns)
log.Debugln("set max open connections to ", *maxOpenConns)
db.SetMaxOpenConns(*maxOpenConns)
log.Debugln("Successfully connected to: ", dsn)
return db
}
// NewExporter returns a new Oracle DB exporter for the provided DSN.
func NewExporter(dsn string) *Exporter {
db := connect(dsn)
return &Exporter{
dsn: dsn,
duration: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Subsystem: exporter,
Name: "last_scrape_duration_seconds",
Help: "Duration of the last scrape of metrics from Oracle DB.",
}),
totalScrapes: prometheus.NewCounter(prometheus.CounterOpts{
Namespace: namespace,
Subsystem: exporter,
Name: "scrapes_total",
Help: "Total number of times Oracle DB was scraped for metrics.",
}),
scrapeErrors: prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: namespace,
Subsystem: exporter,
Name: "scrape_errors_total",
Help: "Total number of times an error occured scraping a Oracle database.",
}, []string{"collector"}),
error: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Subsystem: exporter,
Name: "last_scrape_error",
Help: "Whether the last scrape of metrics from Oracle DB resulted in an error (1 for error, 0 for success).",
}),
up: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Name: "up",
Help: "Whether the Oracle database server is up.",
}),
db: db,
}
}
// Describe describes all the metrics exported by the Oracle DB exporter.
func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
// We cannot know in advance what metrics the exporter will generate
// So we use the poor man's describe method: Run a collect
// and send the descriptors of all the collected metrics. The problem
// here is that we need to connect to the Oracle DB. If it is currently
// unavailable, the descriptors will be incomplete. Since this is a
// stand-alone exporter and not used as a library within other code
// implementing additional metrics, the worst that can happen is that we
// don't detect inconsistent metrics created by this exporter
// itself. Also, a change in the monitored Oracle instance may change the
// exported metrics during the runtime of the exporter.
metricCh := make(chan prometheus.Metric)
doneCh := make(chan struct{})
go func() {
for m := range metricCh {
ch <- m.Desc()
}
close(doneCh)
}()
e.Collect(metricCh)
close(metricCh)
<-doneCh
}
// Collect implements prometheus.Collector.
func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
e.scrape(ch)
ch <- e.duration
ch <- e.totalScrapes
ch <- e.error
e.scrapeErrors.Collect(ch)
ch <- e.up
}
func (e *Exporter) scrape(ch chan<- prometheus.Metric) {
e.totalScrapes.Inc()
var err error
defer func(begun time.Time) {
e.duration.Set(time.Since(begun).Seconds())
if err == nil {
e.error.Set(0)
} else {
e.error.Set(1)
}
}(time.Now())
if err = e.db.Ping(); err != nil {
if strings.Contains(err.Error(), "sql: database is closed") {
log.Infoln("Reconnecting to DB")
e.db = connect(e.dsn)
}
}
if err = e.db.Ping(); err != nil {
log.Errorln("Error pinging oracle:", err)
//e.db.Close()
e.up.Set(0)
return
} else {
log.Debugln("Successfully pinged Oracle database: ")
e.up.Set(1)
}
for _, metric := range metricsToScrap.Metric {
log.Debugln("About to scrape metric: ")
log.Debugln("- Metric MetricsDesc: ", metric.MetricsDesc)
log.Debugln("- Metric Context: ", metric.Context)
log.Debugln("- Metric MetricsType: ", metric.MetricsType)
log.Debugln("- Metric Labels: ", metric.Labels)
log.Debugln("- Metric FieldToAppend: ", metric.FieldToAppend)
log.Debugln("- Metric IgnoreZeroResult: ", metric.IgnoreZeroResult)
log.Debugln("- Metric Request: ", metric.Request)
if len(metric.Request) == 0 {
log.Errorln("Error scraping for ", metric.MetricsDesc, ". Did you forget to define request in your toml file?")
continue
}
if len(metric.MetricsDesc) == 0 {
log.Errorln("Error scraping for query", metric.Request, ". Did you forget to define metricsdesc in your toml file?")
continue
}
if err = ScrapeMetric(e.db, ch, metric); err != nil {
log.Errorln("Error scraping for", metric.Context, "_", metric.MetricsDesc, ":", err)
e.scrapeErrors.WithLabelValues(metric.Context).Inc()
} else {
log.Debugln("Successfully scrapped metric: ", metric.Context)
}
}
}
func GetMetricType(metricType string, metricsType map[string]string) prometheus.ValueType {
var strToPromType = map[string]prometheus.ValueType{
"gauge": prometheus.GaugeValue,
"counter": prometheus.CounterValue,
}
strType, ok := metricsType[strings.ToLower(metricType)]
if !ok {
return prometheus.GaugeValue
}
valueType, ok := strToPromType[strings.ToLower(strType)]
if !ok {
panic(errors.New("Error while getting prometheus type " + strings.ToLower(strType)))
}
return valueType
}
// interface method to call ScrapeGenericValues using Metric struct values
func ScrapeMetric(db *sql.DB, ch chan<- prometheus.Metric, metricDefinition Metric) error {
log.Debugln("Calling function ScrapeGenericValues()")
return ScrapeGenericValues(db, ch, metricDefinition.Context, metricDefinition.Labels,
metricDefinition.MetricsDesc, metricDefinition.MetricsType,
metricDefinition.FieldToAppend, metricDefinition.IgnoreZeroResult,
metricDefinition.Request)
}
// generic method for retrieving metrics.
func ScrapeGenericValues(db *sql.DB, ch chan<- prometheus.Metric, context string, labels []string,
metricsDesc map[string]string, metricsType map[string]string, fieldToAppend string, ignoreZeroResult bool, request string) error {
metricsCount := 0
genericParser := func(row map[string]string) error {
// Construct labels value
labelsValues := []string{}
for _, label := range labels {
labelsValues = append(labelsValues, row[label])
}
// Construct Prometheus values to sent back
for metric, metricHelp := range metricsDesc {
value, err := strconv.ParseFloat(strings.TrimSpace(row[metric]), 64)
// If not a float, skip current metric
if err != nil {
log.Errorln("Unable to convert current value to float (metric=" + metric +
",metricHelp=" + metricHelp + ",value=<" + row[metric] + ">)")
continue
}
log.Debugln("Query result looks like: ", value)
// If metric do not use a field content in metric's name
if strings.Compare(fieldToAppend, "") == 0 {
desc := prometheus.NewDesc(
prometheus.BuildFQName(namespace, context, metric),
metricHelp,
labels, nil,
)
ch <- prometheus.MustNewConstMetric(desc, GetMetricType(metric, metricsType), value, labelsValues...)
// If no labels, use metric name
} else {
desc := prometheus.NewDesc(
prometheus.BuildFQName(namespace, context, cleanName(row[fieldToAppend])),
metricHelp,
nil, nil,
)
ch <- prometheus.MustNewConstMetric(desc, GetMetricType(metric, metricsType), value)
}
metricsCount++
}
return nil
}
err := GeneratePrometheusMetrics(db, genericParser, request)
log.Debugln("ScrapeGenericValues() - metricsCount: ", metricsCount)
if err != nil {
return err
}
if !ignoreZeroResult && metricsCount == 0 {
return errors.New("No metrics found while parsing")
}
return err
}
// inspired by https://kylewbanks.com/blog/query-result-to-map-in-golang
// Parse SQL result and call parsing function to each row
func GeneratePrometheusMetrics(db *sql.DB, parse func(row map[string]string) error, query string) error {
// Add a timeout
timeout, err := strconv.Atoi(*queryTimeout)
if err != nil {
log.Fatal("error while converting timeout option value: ", err)
panic(err)
}
ctx, cancel := context.WithTimeout(context.Background(), time.Duration(timeout)*time.Second)
defer cancel()
rows, err := db.QueryContext(ctx, query)
if ctx.Err() == context.DeadlineExceeded {
return errors.New("Oracle query timed out")
}
if err != nil {
return err
}
cols, err := rows.Columns()
defer rows.Close()
for rows.Next() {
// Create a slice of interface{}'s to represent each column,
// and a second slice to contain pointers to each item in the columns slice.
columns := make([]interface{}, len(cols))
columnPointers := make([]interface{}, len(cols))
for i, _ := range columns {
columnPointers[i] = &columns[i]
}
// Scan the result into the column pointers...
if err := rows.Scan(columnPointers...); err != nil {
return err
}
// Create our map, and retrieve the value for each column from the pointers slice,
// storing it in the map with the name of the column as the key.
m := make(map[string]string)
for i, colName := range cols {
val := columnPointers[i].(*interface{})
m[strings.ToLower(colName)] = fmt.Sprintf("%v", *val)
}
// Call function to parse row
if err := parse(m); err != nil {
return err
}
}
return nil
}
// Oracle gives us some ugly names back. This function cleans things up for Prometheus.
func cleanName(s string) string {
s = strings.Replace(s, " ", "_", -1) // Remove spaces
s = strings.Replace(s, "(", "", -1) // Remove open parenthesis
s = strings.Replace(s, ")", "", -1) // Remove close parenthesis
s = strings.Replace(s, "/", "", -1) // Remove forward slashes
s = strings.Replace(s, "*", "", -1) // Remove asterisks
s = strings.ToLower(s)
return s
}
func main() {
flag.Parse()
log.Infoln("Starting oracledb_exporter " + Version)
dsn := os.Getenv("DATA_SOURCE_NAME")
// Load default metrics
if _, err := toml.DecodeFile(*defaultFileMetrics, &metricsToScrap); err != nil {
log.Errorln(err)
panic(errors.New("Error while loading " + *defaultFileMetrics))
} else {
log.Infoln("Successfully loaded default metrics from: " + *defaultFileMetrics)
}
// If custom metrics, load it
if strings.Compare(*customMetrics, "") != 0 {
if _, err := toml.DecodeFile(*customMetrics, &additionalMetrics); err != nil {
log.Errorln(err)
panic(errors.New("Error while loading " + *customMetrics))
} else {
log.Infoln("Successfully loaded custom metrics from: " + *customMetrics)
}
metricsToScrap.Metric = append(metricsToScrap.Metric, additionalMetrics.Metric...)
} else {
log.Infoln("No custom metrics defined.")
}
exporter := NewExporter(dsn)
prometheus.MustRegister(exporter)
http.Handle(*metricPath, prometheus.Handler())
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
w.Write(landingPage)
})
log.Infoln("Listening on", *listenAddress)
log.Fatal(http.ListenAndServe(*listenAddress, nil))
}