mirror of
https://github.com/prometheus-community/postgres_exporter
synced 2025-04-22 23:15:26 +00:00
112 lines
2.7 KiB
Go
112 lines
2.7 KiB
Go
package servers
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import (
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"database/sql"
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"fmt"
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"github.com/blang/semver"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/common/log"
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"sync"
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)
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// Server describes a connection to a Postgresql database, and describes the
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// metric maps and overrides in-place for it.
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// Also it contains metrics map and query overrides.
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type Server struct {
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db *sql.DB
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labels prometheus.Labels
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master bool
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// Last version used to calculate metric map. If mismatch on scrape,
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// then maps are recalculated.
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lastMapVersion semver.Version
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// Currently active metric map
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metricMap map[string]MetricMapNamespace
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// Currently active query overrides
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queryOverrides map[string]string
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mappingMtx sync.RWMutex
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// Currently cached metrics
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metricCache map[string]cachedMetrics
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cacheMtx sync.Mutex
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}
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// NewServer establishes a new connection using DSN.
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func NewServer(dsn string, opts ...ServerOpt) (*Server, error) {
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fingerprint, err := parseFingerprint(dsn)
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if err != nil {
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return nil, err
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}
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db, err := sql.Open("postgres", dsn)
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if err != nil {
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return nil, err
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}
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db.SetMaxOpenConns(1)
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db.SetMaxIdleConns(1)
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log.Infof("Established new database connection to %q.", fingerprint)
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s := &Server{
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db: db,
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master: false,
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labels: prometheus.Labels{
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serverLabelName: fingerprint,
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},
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metricCache: make(map[string]cachedMetrics),
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}
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for _, opt := range opts {
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opt(s)
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}
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return s, nil
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}
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// Close disconnects from Postgres.
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func (s *Server) Close() error {
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return s.db.Close()
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}
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// Ping checks connection availability and possibly invalidates the connection if it fails.
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func (s *Server) Ping() error {
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if err := s.db.Ping(); err != nil {
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if cerr := s.Close(); cerr != nil {
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log.Errorf("Error while closing non-pinging DB connection to %q: %v", s, cerr)
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}
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return err
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}
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return nil
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}
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// String returns server's fingerprint.
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func (s *Server) String() string {
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return s.labels[serverLabelName]
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}
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// Scrape loads metrics.
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func (s *Server) Scrape(ch chan<- prometheus.Metric, disableSettingsMetrics bool) error {
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s.mappingMtx.RLock()
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defer s.mappingMtx.RUnlock()
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var err error
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if !disableSettingsMetrics && s.master {
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if err = querySettings(ch, s); err != nil {
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err = fmt.Errorf("error retrieving settings: %s", err)
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}
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}
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errMap := queryNamespaceMappings(ch, s)
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if len(errMap) > 0 {
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err = fmt.Errorf("queryNamespaceMappings returned %d errors", len(errMap))
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}
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return err
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}
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// AddQueries adds queries to the builtinMetricMaps and queryOverrides maps.
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// Added queries do not respect version requirements, because it is assumed
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// that the user knows what they are doing with their version of postgres.
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func (s *Server) AddQueries() {
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} |