firehol/netdata

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

package httpcheck

import (
    _ "embed"
    "errors"
    "net/http"
    "regexp"
    "time"

    "github.com/netdata/netdata/go/plugins/plugin/go.d/agent/module"
    "github.com/netdata/netdata/go/plugins/plugin/go.d/pkg/confopt"
    "github.com/netdata/netdata/go/plugins/plugin/go.d/pkg/web"
)

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

func init() {
    module.Register("httpcheck", module.Creator{
        JobConfigSchema: configSchema,
        Defaults: module.Defaults{
            UpdateEvery: 5,
        },
        Create: func() module.Module { return New() },
        Config: func() any { return &Config{} },
    })
}

func New() *HTTPCheck {
    return &HTTPCheck{
        Config: Config{
            HTTPConfig: web.HTTPConfig{
                ClientConfig: web.ClientConfig{
                    Timeout: confopt.Duration(time.Second),
                },
            },
            AcceptedStatuses: []int{200},
        },

        acceptedStatuses: make(map[int]bool),
    }
}

type (
    Config struct {
        UpdateEvery      int `yaml:"update_every,omitempty" json:"update_every"`
        web.HTTPConfig   `yaml:",inline" json:""`
        AcceptedStatuses []int               `yaml:"status_accepted" json:"status_accepted"`
        ResponseMatch    string              `yaml:"response_match,omitempty" json:"response_match"`
        CookieFile       string              `yaml:"cookie_file,omitempty" json:"cookie_file"`
        HeaderMatch      []headerMatchConfig `yaml:"header_match,omitempty" json:"header_match"`
    }
    headerMatchConfig struct {
        Exclude bool   `yaml:"exclude" json:"exclude"`
        Key     string `yaml:"key" json:"key"`
        Value   string `yaml:"value" json:"value"`
    }
)

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

    charts *module.Charts

    httpClient *http.Client

    acceptedStatuses  map[int]bool
    reResponse        *regexp.Regexp
    headerMatch       []headerMatch
    cookieFileModTime time.Time

    metrics metrics
}

func (hc *HTTPCheck) Configuration() any {
    return hc.Config
}

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

    hc.charts = hc.initCharts()

    httpClient, err := hc.initHTTPClient()
    if err != nil {
        hc.Errorf("init HTTP client: %v", err)
        return err
    }
    hc.httpClient = httpClient

    re, err := hc.initResponseMatchRegexp()
    if err != nil {
        hc.Errorf("init response match regexp: %v", err)
        return err
    }
    hc.reResponse = re

    hm, err := hc.initHeaderMatch()
    if err != nil {
        hc.Errorf("init header match: %v", err)
        return err
    }
    hc.headerMatch = hm

    for _, v := range hc.AcceptedStatuses {
        hc.acceptedStatuses[v] = true
    }

    hc.Debugf("using URL %s", hc.URL)
    hc.Debugf("using HTTP timeout %s", hc.Timeout.Duration())
    hc.Debugf("using accepted HTTPConfig statuses %v", hc.AcceptedStatuses)
    if hc.reResponse != nil {
        hc.Debugf("using response match regexp %s", hc.reResponse)
    }

    return nil
}

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

func (hc *HTTPCheck) Charts() *module.Charts {
    return hc.charts
}

func (hc *HTTPCheck) Collect() map[string]int64 {
    mx, err := hc.collect()
    if err != nil {
        hc.Error(err)
    }

    if len(mx) == 0 {
        return nil
    }
    return mx
}

func (hc *HTTPCheck) Cleanup() {
    if hc.httpClient != nil {
        hc.httpClient.CloseIdleConnections()
    }
}