firehol/netdata

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

package weblog

import (
    "errors"
    "fmt"
    "strings"

    "github.com/netdata/netdata/go/plugins/pkg/matcher"
    "github.com/netdata/netdata/go/plugins/plugin/go.d/pkg/logs"
)

type pattern struct {
    name string
    matcher.Matcher
}

func newPattern(up userPattern) (*pattern, error) {
    if up.Name == "" || up.Match == "" {
        return nil, errors.New("empty 'name' or 'match'")
    }

    m, err := matcher.Parse(up.Match)
    if err != nil {
        return nil, err
    }
    return &pattern{name: up.Name, Matcher: m}, nil
}

func (w *WebLog) createURLPatterns() error {
    if len(w.URLPatterns) == 0 {
        w.Debug("skipping URL patterns creating, no patterns provided")
        return nil
    }
    w.Debug("starting URL patterns creating")
    for _, up := range w.URLPatterns {
        p, err := newPattern(up)
        if err != nil {
            return fmt.Errorf("create pattern %+v: %v", up, err)
        }
        w.Debugf("created pattern '%s', type '%T', match '%s'", p.name, p.Matcher, up.Match)
        w.urlPatterns = append(w.urlPatterns, p)
    }
    w.Debugf("created %d URL pattern(s)", len(w.URLPatterns))
    return nil
}

func (w *WebLog) createCustomFields() error {
    if len(w.CustomFields) == 0 {
        w.Debug("skipping custom fields creating, no custom fields provided")
        return nil
    }

    w.Debug("starting custom fields creating")
    w.customFields = make(map[string][]*pattern)
    for i, cf := range w.CustomFields {
        if cf.Name == "" {
            return fmt.Errorf("create custom field: name not set (field %d)", i+1)
        }
        for _, up := range cf.Patterns {
            p, err := newPattern(up)
            if err != nil {
                return fmt.Errorf("create field '%s' pattern %+v: %v", cf.Name, up, err)
            }
            w.Debugf("created field '%s', pattern '%s', type '%T', match '%s'", cf.Name, p.name, p.Matcher, up.Match)
            w.customFields[cf.Name] = append(w.customFields[cf.Name], p)
        }
    }
    w.Debugf("created %d custom field(s)", len(w.CustomFields))
    return nil
}

func (w *WebLog) createCustomTimeFields() error {
    if len(w.CustomTimeFields) == 0 {
        w.Debug("skipping custom time fields creating, no custom time fields provided")
        return nil
    }

    w.Debug("starting custom time fields creating")
    w.customTimeFields = make(map[string][]float64)
    for i, ctf := range w.CustomTimeFields {
        if ctf.Name == "" {
            return fmt.Errorf("create custom field: name not set (field %d)", i+1)
        }
        w.customTimeFields[ctf.Name] = ctf.Histogram
        w.Debugf("created time field '%s', histogram '%v'", ctf.Name, ctf.Histogram)
    }
    w.Debugf("created %d custom time field(s)", len(w.CustomTimeFields))
    return nil
}

func (w *WebLog) createCustomNumericFields() error {
    if len(w.CustomNumericFields) == 0 {
        w.Debug("no custom time fields provided")
        return nil
    }

    w.Debugf("creating custom numeric fields for '%+v'", w.CustomNumericFields)

    w.customNumericFields = make(map[string]bool)

    for i := range w.CustomNumericFields {
        v := w.CustomNumericFields[i]
        if v.Name == "" {
            return fmt.Errorf("custom numeric field (%d): 'name' not set", i+1)
        }
        if v.Units == "" {
            return fmt.Errorf("custom numeric field (%s): 'units' not set", v.Name)
        }
        if v.Multiplier <= 0 {
            v.Multiplier = 1
        }
        if v.Divisor <= 0 {
            v.Divisor = 1
        }
        w.CustomNumericFields[i] = v
        w.customNumericFields[v.Name] = true
    }

    return nil
}

func (w *WebLog) createLogLine() {
    w.line = newEmptyLogLine()

    for v := range w.customFields {
        w.line.custom.fields[v] = struct{}{}
    }
    for v := range w.customTimeFields {
        w.line.custom.fields[v] = struct{}{}
    }
    for v := range w.customNumericFields {
        w.line.custom.fields[v] = struct{}{}
    }
}

func (w *WebLog) createLogReader() error {
    w.Cleanup()
    w.Debug("starting log reader creating")

    reader, err := logs.Open(w.Path, w.ExcludePath, w.Logger)
    if err != nil {
        return fmt.Errorf("creating log reader: %v", err)
    }

    w.Debugf("created log reader, current file '%s'", reader.CurrentFilename())
    w.file = reader

    return nil
}

func (w *WebLog) createParser() error {
    w.Debug("starting parser creating")

    const readLinesNum = 100

    lines, err := logs.ReadLastLines(w.file.CurrentFilename(), readLinesNum)
    if err != nil {
        return fmt.Errorf("failed to read last lines: %v", err)
    }

    var found bool
    for _, line := range lines {
        if line = strings.TrimSpace(line); line == "" {
            continue
        }
        w.Debugf("last line: '%s'", line)

        w.parser, err = w.newParser([]byte(line))
        if err != nil {
            w.Debugf("failed to create parser from line: %v", err)
            continue
        }

        w.line.reset()

        if err = w.parser.Parse([]byte(line), w.line); err != nil {
            w.Debugf("failed to parse line: %v", err)
            continue
        }

        if err = w.line.verify(); err != nil {
            w.Debugf("failed to verify line: %v", err)
            continue
        }

        found = true
        break
    }

    if !found {
        return fmt.Errorf("failed to create log parser (file '%s')", w.file.CurrentFilename())
    }

    return nil
}