2025-02-05 16:35:02 +01:00

102 lines
2.8 KiB
Nim

import std/os
import pkg/chronicles
import pkg/chronos
import pkg/questionable
import pkg/questionable/results
import pkg/datastore
import pkg/datastore/typedds
import pkg/metrics
import ./config
import ./logging
import ./metrics
import ./list
declareGauge(todoNodesGauge, "DHT nodes to be visited")
declareGauge(okNodesGauge, "DHT nodes successfully contacted")
declareGauge(nokNodesGauge, "DHT nodes failed to contact")
type
ApplicationStatus* {.pure.} = enum
Stopped
Stopping
Running
Application* = ref object
status: ApplicationStatus
config*: CrawlerConfig
todoList*: List
okNodes*: List
nokNodes*: List
proc createDatastore(app: Application): ?!TypedDatastore =
without store =? LevelDbDatastore.new(app.config.dataDir), err:
error "Failed to create datastore"
return failure(err)
return success(TypedDatastore.init(store))
proc initializeLists(app: Application): Future[?!void] {.async.} =
without store =? app.createDatastore(), err:
return failure(err)
# We can't extract this into a function because gauges cannot be passed as argument.
# The use of global state in nim-metrics is not pleasant.
proc onTodoMetric(value: int64) =
todoNodesGauge.set(value)
proc onOkMetric(value: int64) =
okNodesGauge.set(value)
proc onNokMetric(value: int64) =
nokNodesGauge.set(value)
app.todoList = List.new("todo", store, onTodoMetric)
app.okNodes = List.new("ok", store, onOkMetric)
app.nokNodes = List.new("nok", store, onNokMetric)
if err =? (await app.todoList.load()).errorOption:
return failure(err)
if err =? (await app.okNodes.load()).errorOption:
return failure(err)
if err =? (await app.nokNodes.load()).errorOption:
return failure(err)
return success()
proc initializeApp(app: Application): Future[?!void] {.async.} =
if err =? (await app.initializeLists()).errorOption:
error "Failed to initialize lists", err = err.msg
return failure(err)
return success()
proc stop*(app: Application) =
app.status = ApplicationStatus.Stopping
proc run*(app: Application) =
app.config = parseConfig()
info "Loaded configuration", config = app.config
# Configure loglevel
updateLogLevel(app.config.logLevel)
# Ensure datadir path exists:
if not existsDir(app.config.dataDir):
createDir(app.config.dataDir)
setupMetrics(app.config.metricsAddress, app.config.metricsPort)
info "Metrics endpoint initialized"
info "Starting application"
app.status = ApplicationStatus.Running
if err =? (waitFor app.initializeApp()).errorOption:
app.status = ApplicationStatus.Stopping
error "Failed to start application", err = err.msg
return
while app.status == ApplicationStatus.Running:
try:
chronos.poll()
except Exception as exc:
error "Unhandled exception", msg = exc.msg
quit QuitFailure
notice "Application closed"