I have vertex class host with property hostname and edge class link with property ports which is a list.
So hosts are connected to each other with link having ports.
I need to find out who is connected to one specific 'myhost' like:
host1.hostname -- link1.ports
host2.hostname -- link2.ports
etc
However, I'm only able to achieve:
host1#rid -- ports1
host2#rid -- ports2
with query like:
select expand(inE(link).include('ports','out*')) from host where hostname = 'myhost'
or I can get hostnames and ports as list, yet not very useful:
[host1.hostname, host2.hostname] -- [link1.ports, link2.ports]
select in('link').hostname,inE('link').ports from host where hostname = 'myhost'
Unwind in that query doesn't do the thing, too.
Is there any proper way to do it?
Did you try the Match statement?
https://orientdb.com/docs/2.2/SQL-Match.html
Try this
match { class: host, as : host1, where: (hostname = "myhost") }
.inE('link'){as: link}
.outV(){as: host2}
return host1.hostname,link.ports, host2.hostname
Related
I have this graph:
Regione -Ha-> Deceduto -alGiornoDeceduti -> Data
and the alGiornoDeceduti edge has the property name. I am trying this query, but it is not working:
match {class:Regione, as:r} -Ha-> {class:Deceduto, as:d} .outE("alGiornoDeceduti"){where:(name=r.name)}.inV() {class:Data, as:dd, where:(data="2020-05-03 00:00:00")} return r.name,d.deceduti,dd.data
I think the error is this:
{where:(name=r.name)}
because if I replace the r.name with for example 'Sardinia' it works.
You can refer to other nodes in the pattern using the $matched keyword, eg.
name = $matched.r.name
I'm learning about creating a k8s cluster on DO using terraform, I've been trying to take the ID of the single K8s node I've created, and reference it from the loadbalancer.
The main reasoning for this is so that I can declare the FQDN in the .tf file.
First, here is the cluster declaration:
variable "digitalocean_token" {}
provider "digitalocean" {
token = "${var.digitalocean_token}"
}
resource "digitalocean_kubernetes_cluster" "foo" {
name = "foo"
region = "nyc1"
version = "1.12.1-do.2"
node_pool {
name = "woker-pool"
size = "s-1vcpu-2gb"
node_count = 1
}
}
And here is the load balancer declaration:
resource "digitalocean_loadbalancer" "foo" {
name = "k8s-lb.nyc1"
region = "nyc1"
forwarding_rule {
entry_port = 80
entry_protocol = "http"
target_port = 80
target_protocol = "http"
}
droplet_ids = ["${digitalocean_kubernetes_cluster.foo.node_pool.0.id}"]
}
output "loadbalancer_ip" {
value = "${digitalocean_loadbalancer.foo.ip}"
}
resource "digitalocean_record" "terraform" {
domain = "example.com" # "${digitalocean_domain.example.name}"
type = "A"
name = "terraform"
value = "${digitalocean_loadbalancer.foo.ip}"
}
# Output the FQDN for the record
output "fqdn" {
value = "${digitalocean_record.terraform.fqdn}"
}
I'm guessing that maybe the digitalocean_loadbalancer resources is only setup to work with individual droplets?
Here are the output errors: when I run terraform apply:
* output.loadbalancer_ip: Resource 'digitalocean_loadbalancer.foo' not found for variable 'digitalocean_loadbalancer.foo.ip'
* digitalocean_record.terraform: Resource 'digitalocean_loadbalancer.foo' not found for variable 'digitalocean_loadbalancer.foo.ip'
* digitalocean_loadbalancer.foo: droplet_ids.0: cannot parse '' as int: strconv.ParseInt: parsing "d4292e64-9c0a-4afb-83fc-83f239bcb4af": invalid syntax
Pt. 2
I added a digitalocean_droplet resource, to see what kind of id was passed to the load balancer.
resource "digitalocean_droplet" "web" {
name = "web-1"
size = "s-1vcpu-1gb"
image = "ubuntu-18-04-x64"
region = "nyc1"
}
digitalocean_kubernetes_cluster.foo.node_pool.0.id = '6ae6a787-d837-4e78-a915-cb52155f66fe'
digitalocean_droplet.web.id = 132533158
So, the digitalocean_loadbalancer resource has an optional droplet_tag argument, which can be used to supply a common tag given to the created nodes/droplets.
However, when declaring a load-balancer inside kubernetes, a new one will still be created. So for now at least, it would appear that defining the domain/CNAME record with terraform isn't possible on digitalocean
You're using the wrong attribute reference for your load balancer droplet ids.
droplet_ids = ["${digitalocean_kubernetes_cluster.foo.node_pool.0.id}"]
This will use the node_pool id linked here
What you actually need to do is use the node_pool nodes id, which is referenced here
droplet_ids = "${digitalocean_kubernetes_cluster.foo.node_pool.0.nodes}"
The next problem you're going to have is that this returns a list of maps, and you'll need to build a list of ids from that. I'm not currently sure how to solve that, I'm afraid, but this should move you along hopefully.
It seems from your answer however, that what you want to do is update DNS for your loadbalancer.
You can do this external-dns using the digitalocean provider
Simply deploy this as a pod, specifying the required configuration, and ensure that the arg --source=service is set.
If you want to go a step further, and allow updating DNS with specific hostname, deploy an ingress controller like nginx-ingress and specify ingresses for your applications. The external-dns deployment (if you set --source=ingress) will the hostname from your ingress and update DNS for you.
I'm trying to recreate the information displayed for the current Wi-Fi network when option-clicking on the Wi-Fi status bar item. One of the parameters shown is the MCS Index, but I can't find any way to query this value using the CWInterface class, which is where I am getting most of the other data:
if let interface = CWWiFiClient.shared().interface() {
rssi = interface.rssiValue()
noise = interface.noiseMeasurement()
// etc.
}
Since both the Wi-Fi status bar item and the airport command line tool display the MCS Index, it seems like there should be some way to query it:
MacBook:~ mark$ /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport -I
agrCtlRSSI: -46
agrExtRSSI: 0
agrCtlNoise: -90
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 878
maxRate: 1300
lastAssocStatus: 0
802.11 auth: open
link auth: wpa2-psk
BSSID: xx:xx:xx:xx:xx:xx
SSID: MyWiFi
MCS: 7
channel: 149,80
I've also seem some Python sample code that seems to indicate that the MCS Index should be available, but I don't see it in the docs or code completion.
Is there some way to get this value through Core WLAN or some other framework, or is this something I need to calculate based on other values?
I found another Python script wifi_status.py
which reports the WiFi status. From the lines
def wifi_status(properties=('bssid', 'channel', 'txRate', 'mcsIndex', 'rssi', 'noise')):
xface = CWWiFiClient.sharedWiFiClient().interface()
while True:
yield({name: getattr(xface, name)() for name in properties})
one can conclude that these attributes can be retrieved with
Key-Value Coding.
And that really works:
if let iface = CWWiFiClient.shared().interface() {
if let mcsIndex = iface.value(forKey: "mcsIndex") as? Int {
print(mcsIndex)
}
}
But I have now idea if that approach is officially supported,
or will work in the future, so use at your own risk.
It's the first time I'm using OMNET++.
I want to start from the very basic stuff to understand how it works.
I successuffly created my first simulation with two hosts continuosly exhanging mesagges (from tictoc example).
What I would like to do now is to simulate a simple client-server wireless communication between one AP and one wireless node. I'm trying to do that using elements from the inet class but I'm stuck and it is not working.
import inet.networklayer.configurator.base.NetworkConfiguratorBase;
import inet.networklayer.configurator.ipv4.IPv4NetworkConfigurator;
import inet.networklayer.configurator.ipv4.IPv4NodeConfigurator;
import inet.node.inet.WirelessHost;
import inet.node.wireless.AccessPoint;
import inet.physicallayer.common.packetlevel.RadioMedium;
import inet.physicallayer.contract.packetlevel.IRadioMedium;
import inet.physicallayer.ieee80211.packetlevel.Ieee80211RadioMedium;
//
// TODO documentation
//
network net
{
string mediumType = default("IdealRadioMedium");
#display("bgb=620,426");
submodules:
wirelessHost1: WirelessHost {
#display("p=423,164");
}
accessPoint1: AccessPoint {
#display("p=147,197");
}
iRadioMedium: <mediumType> like IRadioMedium {
#display("p=523,302");
}
iPv4NetworkConfigurator: IPv4NetworkConfigurator {
#display("p=270,324");
assignDisjunctSubnetAddresses = false;
}
}
and then I created a wirelessHost.cc source file using the tictoc beahviour to make the two nodes communicate.
But it is not working, I get this error:
<!> Error in module (inet::IPv4NodeConfigurator) infrastructure.wirelessHost1.networkLayer.configurator (id=13) during network initialization: Configurator module 'configurator' not found (check the 'networkConfiguratorModule' parameter).
But before doing something, it was another error about the Access Point (could not find wlan[0] module).
Can someone help me to understand how to configure this model?
EDIT
Here's the configuration .ini file
[General]
network = infrastructure
#cmdenv-output-file = omnetpp.log
#debug-on-errors = true
tkenv-plugin-path = ../../../etc/plugins
#record-eventlog = true
**.constraintAreaMinX = 0m
**.constraintAreaMinY = 0m
**.constraintAreaMinZ = 0m
**.constraintAreaMaxX = 600m
**.constraintAreaMaxY = 500m
**.constraintAreaMaxZ = 0m
**.mobility.typename = "StationaryMobility"
**.mobilityType = "StationaryMobility"
# access point
*.accessPoint.wlan[0].mac.address = "004444444444"
*.accessPoint.wlan[0].radio.channelNumber = 11
# host1 is associated with AP1 on channel 0
**.wirelessHost1.wlan[0].mgmt.accessPointAddress = "004444444444"
*.wirelessHost1.**.mgmtType = "Ieee80211MgmtSTASimplified"
# global data rates
**.wlan*.bitrate = 11Mbps
# application level: host1 pings host2
**.numPingApps = 1
*.wirelessHost1.pingApp[0].destAddr = "accessPoint"
*.wirelessHost1.pingApp[0].sendInterval = 10ms
but running the simulation I get
<!> Error in module (inet::ICMP) infrastructure.wirelessHost1.networkLayer.icmp (id=17) at event #4, t=0.008442657441: check_and_cast(): cannot cast (inet::GenericNetworkProtocolControlInfo*) to type 'inet::IPv4ControlInfo *'.
An instance of IPv4NetworkConfigurator in network has to be named configurator. After changing its name your second problem should be resolved too.
Moreover, the name of RadioMedium instance module has to be: radioMedium (instead of iRadioMedium).
EDIT
You have made two mistakes.
AccessPoint does not have network layer, because it only relays and sends MAC frames using MAC layer and MAC addresses - like in real network. As a consequence, it does not have an IP address and it is impossible to send ICMP ping to it.
OMNeT++ allows to use module's name instead of an IP address in ini file, for example **.destAddr = "wirelessHost1". In your ini you are trying to use non existing accessPoint instead of accessPoint1 (which is incorrectly because of the first error).
I suggest adding a new WirelesHost (for example wirelessHost2) and sending ping towards it, i.e.
*.wirelessHost1.pingApp[0].destAddr = "wirelessHost2"
Does anyone know how do I force TCP when using Resolv::DNS?
It seems that when I ask for ANY records, the output is truncated and I get partial results. When I perform many queries (one for each record type) I get more results. I also get inconsistent results (vary between machines, two sequential queries return different results,...)
I thought it could have something to do with UDP being bounded to packet size.
Any idea how I can force it to use TCP? Any other DNS pakcage that I can use?
I had this same problem, wanting to use Resolv for TCP-only queries as I was expecting result sets that were quite large. I ended up digging through Resolv's source code and learned that, by default, TCP queries are only ever performed if the UDP query fails. I found that I could subclass Resolv::DNS and override the each_resource method. Here's my source:
require 'resolv'
# A TCP-only resolver built from `Resolv::DNS`. See the docs for what it's about.
# http://ruby-doc.org/stdlib-1.9.3/libdoc/resolv/rdoc/Resolv/DNS.html
class TcpDNS < Resolv::DNS
# Override fetch_resource to use a TCP requester instead of a UDP requester. This
# is mostly borrowed from `lib/resolv.rb` with the UDP->TCP fallback logic removed.
def each_resource(name, typeclass, &proc)
lazy_initialize
senders = {}
requester = nil
begin
#config.resolv(name) { |candidate, tout, nameserver, port|
requester = make_tcp_requester(nameserver, port)
msg = Message.new
msg.rd = 1
msg.add_question(candidate, typeclass)
unless sender = senders[[candidate, nameserver, port]]
sender = senders[[candidate, nameserver, port]] =
requester.sender(msg, candidate, nameserver, port)
end
begin # HACK
reply, reply_name = requester.request(sender, tout)
rescue
return
end
case reply.rcode
when RCode::NoError
extract_resources(reply, reply_name, typeclass, &proc)
return
when RCode::NXDomain
raise Config::NXDomain.new(reply_name.to_s)
else
raise Config::OtherResolvError.new(reply_name.to_s)
end
}
ensure
requester.close
end
end
end
Then using it is as easy as follows:
TcpDNS.open :nameserver => ns_addrs, :search => '', :ndots => 1 do |dns|
resp = dns.getresources target, Resolv::DNS::Resource::IN::ANY
end