com.twitter.scalding.hraven.reducer_estimation.HRavenHistoryService.scala Maven / Gradle / Ivy
package com.twitter.scalding.hraven.reducer_estimation
import java.io.IOException
import cascading.flow.FlowStep
import com.twitter.hraven.{ Flow, JobDetails }
import com.twitter.hraven.rest.client.HRavenRestClient
import com.twitter.scalding.reducer_estimation._
import org.apache.hadoop.mapred.JobConf
import org.slf4j.LoggerFactory
import scala.collection.JavaConverters._
import com.twitter.hraven.JobDescFactory.{ JOBTRACKER_KEY, RESOURCE_MANAGER_KEY }
import scala.util.{ Failure, Success, Try }
object HRavenClient {
import HRavenHistoryService.jobConfToRichConfig
val apiHostnameKey = "hraven.api.hostname"
val clientConnectTimeoutKey = "hraven.client.connect.timeout"
val clientReadTimeoutKey = "hraven.client.read.timeout"
private final val clientConnectTimeoutDefault = 30000
private final val clientReadTimeoutDefault = 30000
def apply(conf: JobConf): Try[HRavenRestClient] =
conf.getFirstKey(apiHostnameKey)
.map(new HRavenRestClient(_,
conf.getInt(clientConnectTimeoutKey, clientConnectTimeoutDefault),
conf.getInt(clientReadTimeoutKey, clientReadTimeoutDefault)))
}
/**
* Mixin for ReducerEstimators to give them the ability to query hRaven for
* info about past runs.
*/
object HRavenHistoryService extends HistoryService {
private val LOG = LoggerFactory.getLogger(this.getClass)
// List of fields that we consume from fetchTaskDetails api.
// This is sent to hraven service to filter the response data
// and avoid hitting http content length limit on hraven side.
private val TaskDetailFields = List(
"taskType",
"status",
"startTime",
"finishTime").asJava
val RequiredJobConfigs = Seq("cascading.flow.step.num")
case class MissingFieldsException(fields: Seq[String]) extends Exception
/**
* Add some helper methods to JobConf
*/
case class RichConfig(conf: JobConf) {
val MaxFetch = "hraven.reducer.estimator.max.flow.history"
val MaxFetchDefault = 8
def maxFetch: Int = conf.getInt(MaxFetch, MaxFetchDefault)
/**
* Try fields in order until one returns a value.
* Logs a warning if nothing was found.
*/
def getFirstKey(fields: String*): Try[String] =
fields.collectFirst {
case f if conf.get(f) != null => Success(conf.get(f))
}.getOrElse {
LOG.warn("Missing required config param: " + fields.mkString(" or "))
Failure(MissingFieldsException(fields))
}
}
implicit def jobConfToRichConfig(conf: JobConf): RichConfig = RichConfig(conf)
/**
* Fetch flows until it finds one that was successful
* (using "HdfsBytesRead > 0" as a marker for successful jobs since it seems
* that this is only set on completion of jobs)
*
* TODO: query hRaven for successful jobs (first need to add ability to filter
* results in hRaven REST API)
*/
private def fetchSuccessfulFlows(client: HRavenRestClient, cluster: String, user: String, batch: String, signature: String, max: Int, nFetch: Int): Try[Seq[Flow]] =
Try(client.fetchFlowsWithConfig(cluster, user, batch, signature, nFetch, RequiredJobConfigs: _*))
.flatMap { flows =>
Try {
// Ugly mutable code to add task info to flows
flows.asScala.foreach { flow =>
flow.getJobs.asScala.foreach { job =>
// client.fetchTaskDetails might throw IOException
val tasks = client.fetchTaskDetails(flow.getCluster, job.getJobId, TaskDetailFields)
job.addTasks(tasks)
}
}
val successfulFlows = flows.asScala.filter(_.getHdfsBytesRead > 0).take(max)
if (successfulFlows.isEmpty) {
LOG.warn("Unable to find any successful flows in the last " + nFetch + " jobs.")
}
successfulFlows
}
}.recoverWith {
case e: IOException =>
LOG.error("Error making API request to hRaven. HRavenHistoryService will be disabled.")
Failure(e)
}
/**
* Fetch info from hRaven for the last time the given JobStep ran.
* Finds the last successful complete flow and selects the corresponding
* step from it.
*
* @param step FlowStep to get info for
* @return Details about the previous successful run.
*/
def fetchPastJobDetails(step: FlowStep[JobConf], max: Int): Try[Seq[JobDetails]] = {
val conf = step.getConfig
val stepNum = step.getID
def findMatchingJobStep(pastFlow: Flow) =
pastFlow.getJobs.asScala.find { step =>
try {
step.getConfiguration.get("cascading.flow.step.num").toInt == stepNum
} catch {
case _: NumberFormatException => false
}
} orElse {
LOG.warn("No matching job step in the retrieved hRaven flow.")
None
}
def lookupClusterName(client: HRavenRestClient): Try[String] = {
// regex for case matching URL to get hostname out
val hostRegex = """(.*):\d+""".r
// first try resource manager (for Hadoop v2), then fallback to job tracker
conf.getFirstKey(RESOURCE_MANAGER_KEY, JOBTRACKER_KEY).flatMap {
// extract hostname from hostname:port
case hostRegex(host) =>
// convert hostname -> cluster name (e.g. dw2@smf1)
Try(client.getCluster(host))
}
}
val flowsTry = for {
// connect to hRaven REST API
client <- HRavenClient(conf)
// lookup cluster name used by hRaven
cluster <- lookupClusterName(client)
// get identifying info for this job
user <- conf.getFirstKey("hraven.history.user.name", "user.name")
batch <- conf.getFirstKey("batch.desc")
signature <- conf.getFirstKey("scalding.flow.class.signature")
// query hRaven for matching flows
flows <- fetchSuccessfulFlows(client, cluster, user, batch, signature, max, conf.maxFetch)
} yield flows
// Find the FlowStep in the hRaven flow that corresponds to the current step
// *Note*: when hRaven says "Job" it means "FlowStep"
flowsTry.map(flows => flows.flatMap(findMatchingJobStep))
}
override def fetchHistory(info: FlowStrategyInfo, maxHistory: Int): Try[Seq[FlowStepHistory]] =
fetchPastJobDetails(info.step, maxHistory).map { history =>
for {
step <- history
keys = FlowStepKeys(step.getJobName, step.getUser, step.getPriority, step.getStatus, step.getVersion, "")
// update HRavenHistoryService.TaskDetailFields when consuming additional task fields from hraven below
tasks = step.getTasks.asScala.map { t => Task(t.getType, t.getStatus, t.getStartTime, t.getFinishTime) }
} yield toFlowStepHistory(keys, step, tasks)
}
private def toFlowStepHistory(keys: FlowStepKeys, step: JobDetails, tasks: Seq[Task]) =
FlowStepHistory(
keys = keys,
submitTime = step.getSubmitTime,
launchTime = step.getLaunchTime,
finishTime = step.getFinishTime,
totalMaps = step.getTotalMaps,
totalReduces = step.getTotalReduces,
finishedMaps = step.getFinishedMaps,
finishedReduces = step.getFinishedReduces,
failedMaps = step.getFailedMaps,
failedReduces = step.getFailedReduces,
mapFileBytesRead = step.getMapFileBytesRead,
mapFileBytesWritten = step.getMapFileBytesWritten,
reduceFileBytesRead = step.getReduceFileBytesRead,
hdfsBytesRead = step.getHdfsBytesRead,
hdfsBytesWritten = step.getHdfsBytesWritten,
mapperTimeMillis = step.getMapSlotMillis,
reducerTimeMillis = step.getReduceSlotMillis,
reduceShuffleBytes = step.getReduceShuffleBytes,
cost = 0,
tasks = tasks)
}
class HRavenRatioBasedEstimator extends RatioBasedEstimator {
override val historyService = HRavenHistoryService
}
class HRavenRuntimeBasedEstimator extends RuntimeReducerEstimator {
override val historyService = HRavenHistoryService
}
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