netdata/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package coredns

import (
    _ "embed"
    "errors"
    "time"

    "github.com/netdata/netdata/go/go.d.plugin/agent/module"
    "github.com/netdata/netdata/go/go.d.plugin/pkg/matcher"
    "github.com/netdata/netdata/go/go.d.plugin/pkg/prometheus"
    "github.com/netdata/netdata/go/go.d.plugin/pkg/web"

    "github.com/blang/semver/v4"
)

//go:embed "config_schema.json"
var configSchema string

func init() {
    module.Register("coredns", module.Creator{
        JobConfigSchema: configSchema,
        Create:          func() module.Module { return New() },
        Config:          func() any { return &Config{} },
    })
}

func New() *CoreDNS {
    return &CoreDNS{
        Config: Config{
            HTTP: web.HTTP{
                Request: web.Request{
                    URL: "http://127.0.0.1:9153/metrics",
                },
                Client: web.Client{
                    Timeout: web.Duration(time.Second),
                },
            },
        },
        charts:           summaryCharts.Copy(),
        collectedServers: make(map[string]bool),
        collectedZones:   make(map[string]bool),
    }
}

type Config struct {
    UpdateEvery    int `yaml:"update_every,omitempty" json:"update_every"`
    web.HTTP       `yaml:",inline" json:""`
    PerServerStats matcher.SimpleExpr `yaml:"per_server_stats,omitempty" json:"per_server_stats"`
    PerZoneStats   matcher.SimpleExpr `yaml:"per_zone_stats,omitempty" json:"per_zone_stats"`
}

type CoreDNS struct {
    module.Base
    Config `yaml:",inline" json:""`

    prom prometheus.Prometheus

    charts *Charts

    perServerMatcher matcher.Matcher
    perZoneMatcher   matcher.Matcher
    collectedServers map[string]bool
    collectedZones   map[string]bool
    skipVersionCheck bool
    version          *semver.Version
    metricNames      requestMetricsNames
}

func (cd *CoreDNS) Configuration() any {
    return cd.Config
}

func (cd *CoreDNS) Init() error {
    if err := cd.validateConfig(); err != nil {
        cd.Errorf("config validation: %v", err)
        return err
    }

    sm, err := cd.initPerServerMatcher()
    if err != nil {
        cd.Error(err)
        return err
    }
    if sm != nil {
        cd.perServerMatcher = sm
    }

    zm, err := cd.initPerZoneMatcher()
    if err != nil {
        cd.Error(err)
        return err
    }
    if zm != nil {
        cd.perZoneMatcher = zm
    }

    prom, err := cd.initPrometheusClient()
    if err != nil {
        cd.Error(err)
        return err
    }
    cd.prom = prom

    return nil
}

func (cd *CoreDNS) Check() error {
    mx, err := cd.collect()
    if err != nil {
        cd.Error(err)
        return err
    }
    if len(mx) == 0 {
        return errors.New("no metrics collected")

    }
    return nil
}

func (cd *CoreDNS) Charts() *Charts {
    return cd.charts
}

func (cd *CoreDNS) Collect() map[string]int64 {
    mx, err := cd.collect()

    if err != nil {
        cd.Error(err)
        return nil
    }

    return mx
}

func (cd *CoreDNS) Cleanup() {
    if cd.prom != nil && cd.prom.HTTPClient() != nil {
        cd.prom.HTTPClient().CloseIdleConnections()
    }
}