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|
package session
import (
"encoding/base64"
"encoding/json"
"fmt"
"strings"
"github.com/mimecast/dtail/internal/config"
"github.com/mimecast/dtail/internal/omode"
"github.com/mimecast/dtail/internal/regex"
)
// Spec captures the mutable, per-connection workload a DTail client wants to run.
type Spec struct {
Mode omode.Mode `json:"mode"`
Files []string `json:"files"`
Options string `json:"options,omitempty"`
Query string `json:"query,omitempty"`
Regex string `json:"regex,omitempty"`
RegexInvert bool `json:"regex_invert,omitempty"`
Timeout int `json:"timeout,omitempty"`
}
// NewSpec returns a session specification from client args.
func NewSpec(args config.Args) Spec {
files := splitFiles(args.What)
if args.Serverless && len(files) == 0 && supportsServerlessPipe(args.Mode) {
files = []string{"-"}
}
return Spec{
Mode: args.Mode,
Files: files,
Options: args.SerializeOptions(),
Query: strings.TrimSpace(args.QueryStr),
Regex: args.RegexStr,
RegexInvert: args.RegexInvert,
Timeout: args.Timeout,
}
}
// Commands returns the legacy command stream for this session specification.
func (s Spec) Commands() ([]string, error) {
switch {
case s.Mode == omode.HealthClient:
return []string{"health"}, nil
case s.Query != "":
return s.queryCommands()
default:
return s.readCommands(s.Mode.String())
}
}
// StartCommand returns the SESSION START command for this specification.
func (s Spec) StartCommand() (string, error) {
payload, err := s.encodedPayload()
if err != nil {
return "", err
}
return fmt.Sprintf("SESSION START %s", payload), nil
}
// UpdateCommand returns the SESSION UPDATE command for this specification.
func (s Spec) UpdateCommand(generation uint64) (string, error) {
payload, err := s.encodedPayload()
if err != nil {
return "", err
}
if generation == 0 {
return fmt.Sprintf("SESSION UPDATE %s", payload), nil
}
return fmt.Sprintf("SESSION UPDATE %d %s", generation, payload), nil
}
func (s Spec) queryCommands() ([]string, error) {
if s.Mode != omode.MapClient && s.Mode != omode.TailClient {
return nil, fmt.Errorf("session spec query mode requires map or tail mode, got %s", s.Mode)
}
regexValue, err := s.serializedRegex()
if err != nil {
return nil, err
}
commands := []string{fmt.Sprintf("map:%s %s", s.Options, s.Query)}
readMode := "cat"
if s.Mode == omode.TailClient {
readMode = "tail"
}
for _, file := range s.Files {
if s.Timeout > 0 {
commands = append(commands, fmt.Sprintf("timeout %d %s %s %s", s.Timeout, readMode, file, regexValue))
continue
}
commands = append(commands, fmt.Sprintf("%s:%s %s %s", readMode, s.Options, file, regexValue))
}
return commands, nil
}
func (s Spec) readCommands(mode string) ([]string, error) {
switch s.Mode {
case omode.TailClient, omode.CatClient, omode.GrepClient:
default:
return nil, fmt.Errorf("unsupported session mode %s", s.Mode)
}
regexValue, err := s.serializedRegex()
if err != nil {
return nil, err
}
var commands []string
for _, file := range s.Files {
commands = append(commands, fmt.Sprintf("%s:%s %s %s", mode, s.Options, file, regexValue))
}
return commands, nil
}
func (s Spec) serializedRegex() (string, error) {
flag := regex.Default
if s.RegexInvert {
flag = regex.Invert
}
re, err := regex.New(s.Regex, flag)
if err != nil {
return "", err
}
return re.Serialize()
}
func splitFiles(what string) []string {
if strings.TrimSpace(what) == "" {
return nil
}
rawFiles := strings.Split(what, ",")
files := make([]string, 0, len(rawFiles))
for _, file := range rawFiles {
file = strings.TrimSpace(file)
if file == "" {
continue
}
files = append(files, file)
}
return files
}
func supportsServerlessPipe(mode omode.Mode) bool {
switch mode {
case omode.TailClient, omode.CatClient, omode.GrepClient, omode.MapClient:
return true
default:
return false
}
}
func (s Spec) encodedPayload() (string, error) {
payload, err := json.Marshal(s)
if err != nil {
return "", fmt.Errorf("marshal session spec: %w", err)
}
return base64.StdEncoding.EncodeToString(payload), nil
}
|
