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package clients
import (
"context"
"errors"
"fmt"
"runtime"
"strings"
"time"
"github.com/mimecast/dtail/internal/clients/handlers"
"github.com/mimecast/dtail/internal/color"
"github.com/mimecast/dtail/internal/config"
"github.com/mimecast/dtail/internal/io/dlog"
"github.com/mimecast/dtail/internal/mapr"
"github.com/mimecast/dtail/internal/omode"
)
// MaprClientMode determines whether to use cumulative mode or not.
type MaprClientMode int
const (
// DefaultMode behaviour
DefaultMode MaprClientMode = iota
// CumulativeMode means results are added to prev interval
CumulativeMode MaprClientMode = iota
// NonCumulativeMode means results are from 0 for each interval
NonCumulativeMode MaprClientMode = iota
)
// MaprClient is used for running mapreduce aggregations on remote files.
type MaprClient struct {
baseClient
// Global group set for merged mapr aggregation results
globalGroup *mapr.GlobalGroupSet
// The query object (constructed from queryStr)
query *mapr.Query
// Additative result or new result every interval run?
cumulative bool
// The last result string received
lastResult string
}
// NewMaprClient returns a new mapreduce client.
func NewMaprClient(args config.Args, maprClientMode MaprClientMode) (*MaprClient, error) {
if args.QueryStr == "" {
return nil, errors.New("No mapreduce query specified, use '-query' flag")
}
query, err := mapr.NewQuery(args.QueryStr)
if err != nil {
dlog.Client.FatalPanic(args.QueryStr, "Can't parse mapr query", err)
}
// Don't retry connection if in tail mode and no outfile specified.
retry := args.Mode == omode.TailClient && !query.HasOutfile()
var cumulative bool
switch maprClientMode {
case CumulativeMode:
cumulative = true
case NonCumulativeMode:
cumulative = false
default:
// Result is comulative if we are in MapClient mode or with outfile
cumulative = args.Mode == omode.MapClient || query.HasOutfile()
}
dlog.Client.Debug("Cumulative mapreduce mode?", cumulative)
c := MaprClient{
baseClient: baseClient{
Args: args,
throttleCh: make(chan struct{}, args.ConnectionsPerCPU*runtime.NumCPU()),
retry: retry,
},
query: query,
cumulative: cumulative,
}
switch c.query.Table {
case "", ".":
c.RegexStr = "."
case "*":
c.RegexStr = "\\|MAPREDUCE:\\|"
default:
c.RegexStr = fmt.Sprintf("\\|MAPREDUCE:%s\\|", c.query.Table)
}
c.globalGroup = mapr.NewGlobalGroupSet()
c.baseClient.init()
c.baseClient.makeConnections(c)
return &c, nil
}
// Start starts the mapreduce client.
func (c *MaprClient) Start(ctx context.Context, statsCh <-chan string) (status int) {
go c.periodicReportResults(ctx)
status = c.baseClient.Start(ctx, statsCh)
if c.cumulative {
dlog.Client.Debug("Received final mapreduce result")
c.reportResults(true)
}
return
}
// NEXT: Make this a callback function rather trying to use polymorphism to call
// this. This applies to all clients. It will make the code easier to read.
func (c MaprClient) makeHandler(server string) handlers.Handler {
return handlers.NewMaprHandler(server, c.query, c.globalGroup)
}
func (c MaprClient) makeCommands() (commands []string) {
commands = append(commands, fmt.Sprintf("map %s", c.query.RawQuery))
modeStr := "cat"
if c.Mode == omode.TailClient {
modeStr = "tail"
}
for _, file := range strings.Split(c.What, ",") {
regex, err := c.Regex.Serialize()
if err != nil {
dlog.Client.FatalPanic(err)
}
if c.Timeout > 0 {
commands = append(commands, fmt.Sprintf("timeout %d %s %s %s", c.Timeout,
modeStr, file, regex))
continue
}
commands = append(commands, fmt.Sprintf("%s:%s %s %s",
modeStr, c.Args.SerializeOptions(), file, regex))
}
return
}
func (c *MaprClient) periodicReportResults(ctx context.Context) {
rampUpSleep := c.query.Interval / 2
dlog.Client.Debug("Ramp up sleeping before processing mapreduce results", rampUpSleep)
time.Sleep(rampUpSleep)
for {
select {
case <-time.After(c.query.Interval):
dlog.Client.Debug("Gathering interim mapreduce result")
c.reportResults(false)
case <-ctx.Done():
return
}
}
}
func (c *MaprClient) reportResults(finalResult bool) {
if c.query.HasOutfile() {
c.writeResultsToOutfile(finalResult)
return
}
c.printResults()
}
func (c *MaprClient) printResults() {
var result string
var err error
var numRows int
rowsLimit := -1
if c.query.Limit == -1 {
// Limit output to 10 rows when the result is printed to stdout.
// This can be overriden with the limit clause though.
rowsLimit = 10
}
if c.cumulative {
result, numRows, err = c.globalGroup.Result(c.query, rowsLimit)
} else {
result, numRows, err = c.globalGroup.SwapOut().Result(c.query, rowsLimit)
}
if err != nil {
dlog.Client.FatalPanic(err)
}
if result == c.lastResult {
dlog.Client.Debug("Result hasn't changed compared to last time...")
return
}
c.lastResult = result
if numRows == 0 {
dlog.Client.Debug("Empty result set this time...")
return
}
rawQuery := c.query.RawQuery
if config.Client.TermColorsEnable {
rawQuery = color.PaintStrWithAttr(rawQuery,
config.Client.TermColors.MaprTable.RawQueryFg,
config.Client.TermColors.MaprTable.RawQueryBg,
config.Client.TermColors.MaprTable.RawQueryAttr)
}
dlog.Client.Raw(fmt.Sprintf("%s\n", rawQuery))
if rowsLimit > 0 && numRows > rowsLimit {
dlog.Client.Warn(fmt.Sprintf("Got %d results but limited terminal output "+
"to %d rows! Use 'limit' clause to override!", numRows, rowsLimit))
}
dlog.Client.Raw(fmt.Sprintf("%s\n", result))
}
func (c *MaprClient) writeResultsToOutfile(finalResult bool) {
if c.cumulative {
if err := c.globalGroup.WriteResult(c.query, finalResult); err != nil {
dlog.Client.FatalPanic(err)
}
return
}
if err := c.globalGroup.SwapOut().WriteResult(c.query, true); err != nil {
dlog.Client.FatalPanic(err)
}
}
|
