first version of transactor (todo-app working)
This commit is contained in:
Andreas Rumpf
parent
7dc3475e35
commit
df92d3a55d
4 changed files with 161 additions and 83 deletions
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@ -21,9 +21,7 @@ type
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# RequestMessage {.importc.} = ref object
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let conn = newWebSocket("ws://localhost:8080", "karaxdb")
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var gid: MessageId
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var pendingIds = newJDict[MessageId, Message]()
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var pending: int
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var version: int
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#proc loadDb*(url: cstring): Db =
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# result = nil
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@ -34,11 +32,9 @@ proc newTransaction*(): Db =
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proc insert*(head, newdb: Db) =
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newdb.next = head
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#result = newdb
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let expectedVersion = if not head.isNil: head.version + 1 else: 1
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inc gid.int
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let m = Message(kind: NewData, data: newdb.data, version: expectedVersion, id: gid)
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pendingIds[gid] = m
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inc pending
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let expectedVersion = version
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inc version
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let m = Message(kind: NewData, data: newdb.data, version: expectedVersion, id: MessageId(0))
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conn.send(toJson(m))
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proc merge*(newer, older: Db) =
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@ -49,28 +45,15 @@ proc registerOnUpdate*(update: proc(db: Db)) =
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proc (e: MessageEvent) =
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let msg = fromJson[Message](e.data)
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case msg.kind
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of Conflict:
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of Rejected:
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# conflict, so throw away the sent data, don't apply the changes:
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if pending > 0:
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pendingIds.del msg.id
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dec pending
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# server sent data that caused the conflict:
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if msg.data.len > 0:
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let db = Db(data: msg.data, version: msg.version)
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update(db)
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of Accepted:
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kout cstring"accepted", pending
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if pending > 0:
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let d = pendingIds[msg.id]
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# data was not submitted again, so we use the in-memory version
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# of the data:
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let db = Db(data: d.data, version: d.version)
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pendingIds.del msg.id
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dec pending
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update(db)
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kout cstring"rejected"
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of Newdata:
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let db = Db(data: msg.data, version: msg.version)
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update(db)
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of Disconnect:
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kout cstring"disconnected"
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else: kout cstring"something else"
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iterator list*(db: Db, q: Query): Triple =
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# XXX here the datamodel comes in! We must not
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@ -14,4 +14,4 @@ type
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MessageId* = distinct int
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MessageKind* = enum
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Newdata, Conflict, Accepted
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Newdata, Rejected, Disconnect
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@ -1,56 +0,0 @@
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import asynchttpserver, asyncdispatch, asyncnet, "../../../websocket/websocket", common, json
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type
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Message = object
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kind: MessageKind
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id: MessageId
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data: seq[Triple]
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version: int
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proc `%`(id: MessageId): JsonNode = %BiggestInt(id)
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proc `%`(k: MessageKind): JsonNode = %BiggestInt(k)
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proc triplesFromJson(j: JsonNode): seq[Triple] =
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result = newSeq[Triple](j.len)
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var i = 0
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for t in j:
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doAssert t.kind == JArray
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result[i] = [t[0].str, t[1].str, t[2].str]
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inc i
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proc messageFromJson(j: JsonNode): Message =
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Message(kind: MessageKind(j["kind"].num), id: MessageId(j["id"].num),
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data: triplesFromJson(j["data"]), version: j["version"].num.int)
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var server = newAsyncHttpServer()
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proc cb(req: Request) {.async.} =
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let (success, error) = await(verifyWebsocketRequest(req, "karaxdb"))
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if not success:
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echo "WS negotiation failed: " & error
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await req.respond(Http400, "Websocket negotiation failed: " & error)
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req.client.close
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else:
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echo "New websocket customer arrived!"
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while true:
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try:
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var f = await req.client.readData(false)
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echo "(opcode: " & $f.opcode & ", data: " & $f.data.len & ")"
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let m = messageFromJson(f.data.parseJson)
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let om = Message(kind: Accepted, id: m.id, data: @[], version: m.version)
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let oms = $(%*om)
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echo "OUTPUT ", oms
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if f.opcode == Opcode.Text:
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waitFor req.client.sendText(oms, false)
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else:
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echo "protocol error"
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#waitFor req.client.sendBinary(f.data, false)
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except:
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echo getCurrentExceptionMsg()
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break
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req.client.close()
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echo ".. socket went away."
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waitFor server.serve(Port(8080), cb)
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151
src/karaxdb/transactor.nim
Normal file
151
src/karaxdb/transactor.nim
Normal file
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@ -0,0 +1,151 @@
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import asynchttpserver, asyncdispatch, asyncnet, "../../../websocket/websocket", common, json,
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strutils, times
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type
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Message = object
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kind: MessageKind
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id: MessageId
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data: seq[Triple]
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version: int
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proc `%`(id: MessageId): JsonNode = %BiggestInt(id)
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proc `%`(k: MessageKind): JsonNode = %BiggestInt(k)
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proc triplesFromJson(j: JsonNode): seq[Triple] =
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result = newSeq[Triple](j.len)
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var i = 0
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for t in j:
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doAssert t.kind == JArray
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let val = if t[2].kind == JNull: string(nil) else: t[2].str
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result[i] = [t[0].str, t[1].str, val]
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inc i
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proc messageFromJson(j: JsonNode): Message =
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Message(kind: MessageKind(j["kind"].num), id: MessageId(j["id"].num),
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data: triplesFromJson(j["data"]), version: j["version"].num.int)
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proc error(msg: string) = echo msg
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proc warn(msg: string) = echo msg
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type
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Tx = object
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data: string
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version: int
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Client = ref object
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socket: AsyncSocket
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connected: bool
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hostname: string
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lastMessage: float
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rapidMessageCount: int
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Server = ref object
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clients: seq[Client]
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needsUpdate: bool
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txs: seq[Tx]
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version: int
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proc newClient(socket: AsyncSocket, hostname: string): Client =
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Client(socket: socket, connected: true, hostname: hostname)
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proc `$`(client: Client): string =
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"Client(ip: $1)" % [client.hostname]
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proc updateClients(server: Server) {.async.} =
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while true:
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var needsUpdate = false
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for client in server.clients:
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if not client.connected:
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needsUpdate = true
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break
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server.needsUpdate = server.needsUpdate or needsUpdate
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if server.needsUpdate and server.txs.len != 0:
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var someDead = false
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# perform a copy to prevent the race condition:
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var txs = server.txs
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setLen(server.txs, 0)
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for tx in txs:
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for c in server.clients:
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if c.connected:
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await c.socket.sendText(tx.data, false)
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else:
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someDead = true
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if someDead:
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var i = 0
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while i < server.clients.len:
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if not server.clients[i].connected: del(server.clients, i)
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else: inc i
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server.needsUpdate = false
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# let other stuff in the main loop run:
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await sleepAsync(10)
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proc processMessage(server: Server, client: Client, data: string) {.async.} =
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# Check if last message was relatively recent. If so, kick the user.
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echo "processMessage ", data
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if epochTime() - client.lastMessage < 0.1: # 100ms
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client.rapidMessageCount.inc
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else:
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client.rapidMessageCount = 0
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client.lastMessage = epochTime()
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if client.rapidMessageCount > 10:
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warn("Client ($1) is firing messages too rapidly. Killing." % $client)
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client.connected = false
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let msgj = parseJson(data)
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let msg = messageFromJson(msgj)
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case msg.kind
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of Newdata:
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if msg.version == server.version:
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server.txs.add Tx(data: data, version: msg.version)
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server.needsUpdate = true
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inc server.version
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else:
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let om = Message(kind: Rejected, id: msg.id, data: @[], version: server.version)
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await client.socket.sendText($(%*om), false)
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else:
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# either Disconnect or an invalid message type:
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client.connected = false
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server.needsUpdate = true
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proc processClient(server: Server, client: Client) {.async.} =
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while client.connected:
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var frameFut = client.socket.readData(false)
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yield frameFut
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if frameFut.failed:
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error("Error occurred handling client messages.\n" &
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frameFut.error.msg)
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client.connected = false
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break
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let frame = frameFut.read()
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if frame.opcode == Opcode.Text:
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let processFut = processMessage(server, client, frame.data)
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if processFut.failed:
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error("Client ($1) attempted to send bad JSON? " % $client & "\n" &
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processFut.error.msg)
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client.connected = false
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client.socket.close()
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proc onRequest(server: Server, req: Request) {.async.} =
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let (success, error) = await verifyWebsocketRequest(req, "karaxdb")
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if success:
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echo("Client connected from ", req.hostname)
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server.clients.add(newClient(req.client, req.hostname))
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asyncCheck processClient(server, server.clients[^1])
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else:
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echo("WS negotiation failed: ", error)
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await req.respond(Http400, "WebSocket negotiation failed: " & error)
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req.client.close()
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proc main =
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let httpServer = newAsyncHttpServer()
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let server = Server(clients: @[], txs: @[])
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proc cb(req: Request): Future[void] {.async.} = await onRequest(server, req)
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asyncCheck updateClients(server)
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waitFor httpServer.serve(Port(8080), cb)
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main()
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