func FatalWithMessage(arvLogger *logger.Logger, message string) {
	if arvLogger != nil {
		arvLogger.FinalUpdate(func(p map[string]interface{}, e map[string]interface{}) {
			p["FATAL"] = message
			runInfo := logger.GetOrCreateMap(p, "run_info")
			runInfo["finished_at"] = time.Now()
		})
	}

	log.Fatalf(message)
}

func GetServerStatus(arvLogger *logger.Logger,
	keepServer ServerAddress,
	client http.Client) {
	url := fmt.Sprintf("http://%s:%d/status.json",
		keepServer.Host,
		keepServer.Port)

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := make(map[string]interface{})
			serverInfo["status_request_sent_at"] = now
			serverInfo["host"] = keepServer.Host
			serverInfo["port"] = keepServer.Port

			keepInfo[keepServer.Uuid] = serverInfo
		})
	}

	resp, err := client.Get(url)
	if err != nil {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Error getting keep status from %s: %v", url, err))
	} else if resp.StatusCode != 200 {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Received error code %d in response to request "+
				"for %s status: %s",
				resp.StatusCode, url, resp.Status))
	}

	var keepStatus map[string]interface{}
	decoder := json.NewDecoder(resp.Body)
	decoder.UseNumber()
	err = decoder.Decode(&keepStatus)
	if err != nil {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Error decoding keep status from %s: %v", url, err))
	}

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := keepInfo[keepServer.Uuid].(map[string]interface{})
			serverInfo["status_response_processed_at"] = now
			serverInfo["status"] = keepStatus
		})
	}
}

// Summarize results from keep server
func (readServers *ReadServers) Summarize(arvLogger *logger.Logger) {
	readServers.BlockReplicationCounts = make(map[int]int)
	for _, infos := range readServers.BlockToServers {
		replication := len(infos)
		readServers.BlockReplicationCounts[replication]++
	}

	if arvLogger != nil {
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			keepInfo["distinct_blocks_stored"] = len(readServers.BlockToServers)
		})
	}
}

// Useful to call at the begining of execution to log info about the
// current run.
func LogRunInfo(arvLogger *logger.Logger) {
	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			runInfo := logger.GetOrCreateMap(p, "run_info")
			runInfo["started_at"] = now
			runInfo["args"] = os.Args
			hostname, err := os.Hostname()
			if err != nil {
				runInfo["hostname_error"] = err.Error()
			} else {
				runInfo["hostname"] = hostname
			}
			runInfo["pid"] = os.Getpid()
		})
	}
}

// Summarize the collections read
func (readCollections *ReadCollections) Summarize(arvLogger *logger.Logger) {
	readCollections.OwnerToCollectionSize = make(map[string]int)
	readCollections.BlockToDesiredReplication = make(map[blockdigest.DigestWithSize]int)
	numCollections := len(readCollections.UUIDToCollection)
	readCollections.CollectionUUIDToIndex = make(map[string]int, numCollections)
	readCollections.CollectionIndexToUUID = make([]string, 0, numCollections)
	readCollections.BlockToCollectionIndices = make(map[blockdigest.DigestWithSize][]int)

	for _, coll := range readCollections.UUIDToCollection {
		collectionIndex := len(readCollections.CollectionIndexToUUID)
		readCollections.CollectionIndexToUUID =
			append(readCollections.CollectionIndexToUUID, coll.UUID)
		readCollections.CollectionUUIDToIndex[coll.UUID] = collectionIndex

		readCollections.OwnerToCollectionSize[coll.OwnerUUID] =
			readCollections.OwnerToCollectionSize[coll.OwnerUUID] + coll.TotalSize

		for block, size := range coll.BlockDigestToSize {
			locator := blockdigest.DigestWithSize{Digest: block, Size: uint32(size)}
			readCollections.BlockToCollectionIndices[locator] =
				append(readCollections.BlockToCollectionIndices[locator],
					collectionIndex)
			storedReplication := readCollections.BlockToDesiredReplication[locator]
			if coll.ReplicationLevel > storedReplication {
				readCollections.BlockToDesiredReplication[locator] =
					coll.ReplicationLevel
			}
		}
	}

	if arvLogger != nil {
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			collectionInfo := logger.GetOrCreateMap(p, "collection_info")
			// Since maps are shallow copied, we run a risk of concurrent
			// updates here. By copying results.OwnerToCollectionSize into
			// the log, we're assuming that it won't be updated.
			collectionInfo["owner_to_collection_size"] =
				readCollections.OwnerToCollectionSize
			collectionInfo["distinct_blocks_named"] =
				len(readCollections.BlockToDesiredReplication)
		})
	}

	return
}

// WritePullLists writes each pull list to a file.
// The filename is based on the hostname.
//
// This is just a hack for prototyping, it is not expected to be used
// in production.
func WritePullLists(arvLogger *logger.Logger,
	pullLists map[string]PullList,
	dryRun bool) error {
	r := strings.NewReplacer(":", ".")

	for host, list := range pullLists {
		if arvLogger != nil {
			// We need a local variable because Update doesn't call our mutator func until later,
			// when our list variable might have been reused by the next loop iteration.
			host := host
			listLen := len(list)
			arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
				pullListInfo := logger.GetOrCreateMap(p, "pull_list_len")
				pullListInfo[host] = listLen
			})
		}

		if dryRun {
			log.Print("dry run, not sending pull list to service %s with %d blocks", host, len(list))
			continue
		}

		filename := fmt.Sprintf("pull_list.%s", r.Replace(RemoveProtocolPrefix(host)))
		pullListFile, err := os.Create(filename)
		if err != nil {
			return err
		}
		defer pullListFile.Close()

		enc := json.NewEncoder(pullListFile)
		err = enc.Encode(list)
		if err != nil {
			return err
		}
		log.Printf("Wrote pull list to %s.", filename)
	}

	return nil
}

// CreateIndexRequest to the keep server
func CreateIndexRequest(arvLogger *logger.Logger,
	keepServer ServerAddress,
	arv arvadosclient.ArvadosClient) (req *http.Request, err error) {
	url := fmt.Sprintf("http://%s:%d/index", keepServer.Host, keepServer.Port)
	log.Println("About to fetch keep server contents from " + url)

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := keepInfo[keepServer.UUID].(map[string]interface{})
			serverInfo["index_request_sent_at"] = now
		})
	}

	req, err = http.NewRequest("GET", url, nil)
	if err != nil {
		return req, fmt.Errorf("Error building http request for %s: %v", url, err)
	}

	req.Header.Add("Authorization", "OAuth2 "+arv.ApiToken)
	return req, err
}

func CreateIndexRequest(arvLogger *logger.Logger,
	keepServer ServerAddress) (req *http.Request) {
	url := fmt.Sprintf("http://%s:%d/index", keepServer.Host, keepServer.Port)
	log.Println("About to fetch keep server contents from " + url)

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := keepInfo[keepServer.Uuid].(map[string]interface{})
			serverInfo["index_request_sent_at"] = now
		})
	}

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Error building http request for %s: %v", url, err))
	}

	req.Header.Add("Authorization",
		fmt.Sprintf("OAuth2 %s", GetDataManagerToken(arvLogger)))
	return
}

func ReadServerResponse(arvLogger *logger.Logger,
	keepServer ServerAddress,
	resp *http.Response) (response ServerResponse) {

	if resp.StatusCode != 200 {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Received error code %d in response to request "+
				"for %s index: %s",
				resp.StatusCode, keepServer.String(), resp.Status))
	}

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := keepInfo[keepServer.Uuid].(map[string]interface{})
			serverInfo["index_response_received_at"] = now
		})
	}

	response.Address = keepServer
	response.Contents.BlockDigestToInfo =
		make(map[blockdigest.DigestWithSize]BlockInfo)
	reader := bufio.NewReader(resp.Body)
	numLines, numDuplicates, numSizeDisagreements := 0, 0, 0
	for {
		numLines++
		line, err := reader.ReadString('\n')
		if err == io.EOF {
			loggerutil.FatalWithMessage(arvLogger,
				fmt.Sprintf("Index from %s truncated at line %d",
					keepServer.String(), numLines))
		} else if err != nil {
			loggerutil.FatalWithMessage(arvLogger,
				fmt.Sprintf("Error reading index response from %s at line %d: %v",
					keepServer.String(), numLines, err))
		}
		if line == "\n" {
			if _, err := reader.Peek(1); err == nil {
				extra, _ := reader.ReadString('\n')
				loggerutil.FatalWithMessage(arvLogger,
					fmt.Sprintf("Index from %s had trailing data at line %d after EOF marker: %s",
						keepServer.String(), numLines+1, extra))
			} else if err != io.EOF {
				loggerutil.FatalWithMessage(arvLogger,
					fmt.Sprintf("Index from %s had read error after EOF marker at line %d: %v",
						keepServer.String(), numLines, err))
			}
			numLines--
			break
		}
		blockInfo, err := parseBlockInfoFromIndexLine(line)
		if err != nil {
			loggerutil.FatalWithMessage(arvLogger,
				fmt.Sprintf("Error parsing BlockInfo from index line "+
					"received from %s: %v",
					keepServer.String(),
					err))
		}

		if storedBlock, ok := response.Contents.BlockDigestToInfo[blockInfo.Digest]; ok {
			// This server returned multiple lines containing the same block digest.
			numDuplicates += 1
			// Keep the block that's newer.
			if storedBlock.Mtime < blockInfo.Mtime {
				response.Contents.BlockDigestToInfo[blockInfo.Digest] = blockInfo
			}
		} else {
			response.Contents.BlockDigestToInfo[blockInfo.Digest] = blockInfo
		}
	}

	log.Printf("%s index contained %d lines with %d duplicates with "+
		"%d size disagreements",
		keepServer.String(),
		numLines,
		numDuplicates,
		numSizeDisagreements)

	if arvLogger != nil {
		now := time.Now()
		arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
			keepInfo := logger.GetOrCreateMap(p, "keep_info")
			serverInfo := keepInfo[keepServer.Uuid].(map[string]interface{})

			serverInfo["processing_finished_at"] = now
			serverInfo["lines_received"] = numLines
			serverInfo["duplicates_seen"] = numDuplicates
			serverInfo["size_disagreements_seen"] = numSizeDisagreements
		})
	}
	resp.Body.Close()
	return
}

func singlerun() error {
	arv, err := arvadosclient.MakeArvadosClient()
	if err != nil {
		log.Fatalf("Error setting up arvados client %s", err.Error())
	}

	if is_admin, err := util.UserIsAdmin(arv); err != nil {
		log.Fatalf("Error querying current arvados user %s", err.Error())
	} else if !is_admin {
		log.Fatalf("Current user is not an admin. Datamanager can only be run by admins.")
	}

	var arvLogger *logger.Logger
	if logEventTypePrefix != "" {
		arvLogger = logger.NewLogger(logger.LoggerParams{
			Client:          arv,
			EventTypePrefix: logEventTypePrefix,
			WriteInterval:   time.Second * time.Duration(logFrequencySeconds)})
	}

	loggerutil.LogRunInfo(arvLogger)
	if arvLogger != nil {
		arvLogger.AddWriteHook(loggerutil.LogMemoryAlloc)
	}

	var (
		dataFetcher     summary.DataFetcher
		readCollections collection.ReadCollections
		keepServerInfo  keep.ReadServers
	)

	if summary.ShouldReadData() {
		dataFetcher = summary.ReadData
	} else {
		dataFetcher = BuildDataFetcher(arv)
	}

	dataFetcher(arvLogger, &readCollections, &keepServerInfo)

	summary.MaybeWriteData(arvLogger, readCollections, keepServerInfo)

	buckets := summary.BucketReplication(readCollections, keepServerInfo)
	bucketCounts := buckets.Counts()

	replicationSummary := buckets.SummarizeBuckets(readCollections)
	replicationCounts := replicationSummary.ComputeCounts()

	log.Printf("Blocks In Collections: %d, "+
		"\nBlocks In Keep: %d.",
		len(readCollections.BlockToDesiredReplication),
		len(keepServerInfo.BlockToServers))
	log.Println(replicationCounts.PrettyPrint())

	log.Printf("Blocks Histogram:")
	for _, rlbss := range bucketCounts {
		log.Printf("%+v: %10d",
			rlbss.Levels,
			rlbss.Count)
	}

	kc, err := keepclient.MakeKeepClient(&arv)
	if err != nil {
		loggerutil.FatalWithMessage(arvLogger,
			fmt.Sprintf("Error setting up keep client %s", err.Error()))
	}

	// Log that we're finished. We force the recording, since go will
	// not wait for the write timer before exiting.
	if arvLogger != nil {
		defer arvLogger.FinalUpdate(func(p map[string]interface{}, e map[string]interface{}) {
			summaryInfo := logger.GetOrCreateMap(p, "summary_info")
			summaryInfo["block_replication_counts"] = bucketCounts
			summaryInfo["replication_summary"] = replicationCounts
			p["summary_info"] = summaryInfo

			p["run_info"].(map[string]interface{})["finished_at"] = time.Now()
		})
	}

	pullServers := summary.ComputePullServers(kc,
		&keepServerInfo,
		readCollections.BlockToDesiredReplication,
		replicationSummary.UnderReplicatedBlocks)

	pullLists := summary.BuildPullLists(pullServers)

	trashLists, trashErr := summary.BuildTrashLists(kc,
		&keepServerInfo,
		replicationSummary.KeepBlocksNotInCollections)

	summary.WritePullLists(arvLogger, pullLists)

	if trashErr != nil {
		return err
	} else {
		keep.SendTrashLists(keep.GetDataManagerToken(arvLogger), kc, trashLists)
	}

	return nil
}

// SendTrashLists to trash queue
func SendTrashLists(arvLogger *logger.Logger, kc *keepclient.KeepClient, spl map[string]TrashList, dryRun bool) (errs []error) {
	count := 0
	barrier := make(chan error)

	client := kc.Client

	for url, v := range spl {
		if arvLogger != nil {
			// We need a local variable because Update doesn't call our mutator func until later,
			// when our list variable might have been reused by the next loop iteration.
			url := url
			trashLen := len(v)
			arvLogger.Update(func(p map[string]interface{}, e map[string]interface{}) {
				trashListInfo := logger.GetOrCreateMap(p, "trash_list_len")
				trashListInfo[url] = trashLen
			})
		}

		if dryRun {
			log.Printf("dry run, not sending trash list to service %s with %d blocks", url, len(v))
			continue
		}

		count++
		log.Printf("Sending trash list to %v", url)

		go (func(url string, v TrashList) {
			pipeReader, pipeWriter := io.Pipe()
			go (func() {
				enc := json.NewEncoder(pipeWriter)
				enc.Encode(v)
				pipeWriter.Close()
			})()

			req, err := http.NewRequest("PUT", fmt.Sprintf("%s/trash", url), pipeReader)
			if err != nil {
				log.Printf("Error creating trash list request for %v error: %v", url, err.Error())
				barrier <- err
				return
			}

			req.Header.Add("Authorization", "OAuth2 "+kc.Arvados.ApiToken)

			// Make the request
			var resp *http.Response
			if resp, err = client.Do(req); err != nil {
				log.Printf("Error sending trash list to %v error: %v", url, err.Error())
				barrier <- err
				return
			}

			log.Printf("Sent trash list to %v: response was HTTP %v", url, resp.Status)

			io.Copy(ioutil.Discard, resp.Body)
			resp.Body.Close()

			if resp.StatusCode != 200 {
				barrier <- errors.New(fmt.Sprintf("Got HTTP code %v", resp.StatusCode))
			} else {
				barrier <- nil
			}
		})(url, v)
	}

	for i := 0; i < count; i++ {
		b := <-barrier
		if b != nil {
			errs = append(errs, b)
		}
	}

	return errs
}