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OPC Publisher
This reference implementation demonstrates how to connect to existing OPC UA servers and publishes JSON encoded telemetry data from these servers in OPC UA "Pub/Sub" format (using a JSON payload) to Azure IoT Hub. All transport protocols supported by the Azure IoTHub client SDK can be used, i.e. HTTPS, AMQP and MQTT.
This application, apart from including an OPC UA client for connecting to existing OPC UA servers you have on your network, also includes an OPC UA server on port 62222 that can be used to manage what gets published and offers IoTHub direct methods to do the same.
The application is implemented using .NET Core technology and is able to run on the platforms supported by .NET Core.
OPC Publisher implements a retry logic to establish connections to endpoints which have not responded to a certain number of keep alive requests, for example if the OPC UA server on this endpoint had a power outage.
For each distinct publishing interval to an OPC UA server it creates a separate subscription over which all nodes with this publishing interval are updated.
OPC Publisher supports batching of the data sent to IoTHub, to reduce network load. This batching is sending a packet to IoTHub only if the configured package size is reached.
This application uses the OPC Foundations's OPC UA reference stack as nuget packages and therefore licensing of their nuget packages apply. Visit https://opcfoundation.org/license/redistributables/1.3/ for the licensing terms.
| Branch | Status |
|---|---|
| master |  |
Building the application
The application requires the .NET Core SDK 2.1.
As native Windows application
Open the opcpublisher.sln project with Visual Studio 2017 and build the solution by hitting F7.
As Docker container
Depending if you use Docker Linux or Docker Windows containers, there are different configuration files (Dockerfile or Dockerfile.Windows) to use for building the container. From the root of the repository, in a console, type:
docker build -f <docker-configfile-to-use> -t <your-container-name> .
The -f option for docker build is optional and the default is to use Dockerfile. Docker also support building directly from a git repository, which means you also can build a Linux container by:
docker build -t <your-container-name> https://github.com/Azure/iot-edge-opc-publisher
Note: if you want to have correct version information, please install gitversion and run it with the following command line in the root of the repository: gitversion . /updateassemblyinfo /ensureassemblyinfo updateassemblyinfofilename opcpublisher/AssemblyInfo.cs
Configuration of the OPC UA nodes to publish
Configuration to publish data changes via configuration file
The easiest way to configure the OPC UA nodes to publish is via configuration file. The configuration file format is documented in publishednodes.json in this repository.
Configuration file syntax has changed over time and OPC Publisher still can read old formats, but converts them into the latest format when persisting the configuration.
An example for the format of the configuration file is:
[
{
"EndpointUrl": "opc.tcp://testserver:62541/Quickstarts/ReferenceServer",
"UseSecurity": false,
"OpcNodes": [
{
"Id": "i=2258",
"OpcSamplingInterval": 2000,
"OpcPublishingInterval": 5000,
"DisplayName": "Current time"
}
]
}
]
Configuration to publish events via configuration file
To publish OPC UA events you use the same configuration file as for data changes. An example for publishing events which are generated by the SimpleEvents server, which can be found in the OPC Foundation repository is:
[
{
"EndpointUrl": "opc.tcp://testserver:62563/Quickstarts/SimpleEventsServer",
"OpcEvents": [
{
"Id": "i=2253",
"DisplayName": "SimpleEventServerEvents",
"SelectClauses": [
{
"TypeId": "i=2041",
"BrowsePaths": [
"EventId"
]
},
{
"TypeId": "i=2041",
"BrowsePaths": [
"Message"
]
},
{
"TypeId": "nsu=http://opcfoundation.org/Quickstarts/SimpleEvents;i=235",
"BrowsePaths": [
"/2:CycleId"
]
},
{
"TypeId": "nsu=http://opcfoundation.org/Quickstarts/SimpleEvents;i=235",
"BrowsePaths": [
"/2:CurrentStep"
]
}
],
"WhereClause": [
{
"Operator": "OfType",
"Operands": [
{
"Literal": "ns=2;i=235"
}
]
}
]
}
]
}
]
Configuration via OPC UA method calls
OPC Publisher has an OPC UA Server integrated, which can be accessed on port 62222. If the hostname is publisher, then the URI of the endpoint is: opc.tcp://publisher:62222/UA/Publisher
This endpoint exposes five methods:
- PublishNode
- UnpublishNode
- GetPublishedNodes
- IoTHubDirectMethod (see below)
Configuration via IoTHub direct function calls
OPC Publisher implements the following IoTHub direct method calls, which can be called when OPC Publisher runs standalone or in IoT Edge:
- PublishNodes
- UnpublishNodes
- UnpublishAllNodes
- GetConfiguredEndpoints
- GetConfiguredNodesOnEndpoint
- GetDiagnosticInfo
- GetDiagnosticLog
- GetDiagnosticStartupLog
- ExitApplication
- GetInfo
The format of the JSON payload of the method request and responses are defined in the file opcpublisher/HubMethodModels.cs.
If you call a unknown method on the module, it responds with a string, saying the method is not implemented. This can be used to ping the module.
Configuring the telemetry published to IoTHub
When OPC Publisher gets notified about a value change in one of the configured published nodes, it generates a JSON formatted message, which is sent to IoTHub.
The content of this JSON formatted message can be configured via a configuration file. If no configuration file is specified via the --tc option a default configuration is used,
which is compatible with the Connected factory Preconfigured Solution.
If OPC Publisher is configured to batch messages, then they are sent as a valid JSON array.
The data which is ingested is taken from three sources:
- the OPC Publisher node configuration for the node
- the MonitoredItem object of the OPC UA stack for which OPC Publisher got a notification
- the argument passed to this notification, which provides details on the data value change
The telemetry which is put into the JSON formatted message is a selection of important properties of these objects. If you need more properties, you need to change the OPC Publisher code base.
The syntax of the configuration file is as follows:
// The configuration settings file consists of two objects:
// 1) The 'Defaults' object, which defines defaults for the telemetry configuration
// 2) An array 'EndpointSpecific' of endpoint specific configuration
// Both objects are optional and if they are not specified, then publisher uses
// its internal default configuration, which generates telemetry messages compatible
// with the Microsoft Connected factory Preconfigured Solution (https://github.com/Azure/azure-iot-connected-factory).
// A JSON telemetry message for Connected factory looks like:
// {
// "NodeId": "i=2058",
// "ApplicationUri": "urn:myopcserver",
// "DisplayName": "CurrentTime",
// "Value": {
// "Value": "10.11.2017 14:03:17",
// "SourceTimestamp": "2017-11-10T14:03:17Z"
// }
// }
// The 'Defaults' object in the sample below, are similar to what publisher is
// using as its internal default telemetry configuration.
{
"Defaults": {
// The first two properties ('EndpointUrl' and 'NodeId' are configuring data
// taken from the OpcPublisher node configuration.
"EndpointUrl": {
// The following three properties can be used to configure the 'EndpointUrl'
// property in the JSON message send by publisher to IoTHub.
// Publish controls if the property should be part of the JSON message at all.
"Publish": false,
// Pattern is a regular expression, which is applied to the actual value of the
// property (here 'EndpointUrl').
// If this key is ommited (which is the default), then no regex matching is done
// at all, which improves performance.
// If the key is used you need to define groups in the regular expression.
// Publisher applies the regular expression and then concatenates all groups
// found and use the resulting string as the value in the JSON message to
//sent to IoTHub.
// This example mimics the default behaviour and defines a group,
// which matches the conplete value:
"Pattern": "(.*)",
// Here some more exaples for 'Pattern' values and the generated result:
// "Pattern": "i=(.*)"
// defined for Defaults.NodeId.Pattern, will generate for the above sample
// a 'NodeId' value of '2058'to be sent by publisher
// "Pattern": "(i)=(.*)"
// defined for Defaults.NodeId.Pattern, will generate for the above sample
// a 'NodeId' value of 'i2058' to be sent by publisher
// Name allows you to use a shorter string as property name in the JSON message
// sent by publisher. By default the property name is unchanged and will be
// here 'EndpointUrl'.
// The 'Name' property can only be set in the 'Defaults' object to ensure
// all messages from publisher sent to IoTHub have a similar layout.
"Name": "EndpointUrl"
},
"NodeId": {
"Publish": true,
// If you set Defaults.NodeId.Name to "ni", then the "NodeId" key/value pair
// (from the above example) will change to:
// "ni": "i=2058",
"Name": "NodeId"
},
// The MonitoredItem object is configuring the data taken from the MonitoredItem
// OPC UA object for published nodes.
"MonitoredItem": {
// If you set the Defaults.MonitoredItem.Flat to 'false', then a
// 'MonitoredItem' object will appear, which contains 'ApplicationUri'
// and 'DisplayNode' proerties:
// "NodeId": "i=2058",
// "MonitoredItem": {
// "ApplicationUri": "urn:myopcserver",
// "DisplayName": "CurrentTime",
// }
// The 'Flat' property can only be used in the 'MonitoredItem' and
// 'Value' objects of the 'Defaults' object and will be used
// for all JSON messages sent by publisher.
"Flat": true,
"ApplicationUri": {
"Publish": true,
"Name": "ApplicationUri"
},
"DisplayName": {
"Publish": true,
"Name": "DisplayName"
}
},
// The Value object is configuring the properties taken from the event object
// the OPC UA stack provided in the value change notification event.
"Value": {
// If you set the Defaults.Value.Flat to 'true', then the 'Value'
// object will disappear completely and the 'Value' and 'SourceTimestamp'
// members won't be nested:
// "DisplayName": "CurrentTime",
// "Value": "10.11.2017 14:03:17",
// "SourceTimestamp": "2017-11-10T14:03:17Z"
// The 'Flat' property can only be used for the 'MonitoredItem' and 'Value'
// objects of the 'Defaults' object and will be used for all
// messages sent by publisher.
"Flat": false,
"Value": {
"Publish": true,
"Name": "Value"
},
"SourceTimestamp": {
"Publish": true,
"Name": "SourceTimestamp"
},
// 'StatusCode' is the 32 bit OPC UA status code
"StatusCode": {
"Publish": false,
"Name": "StatusCode"
// 'Pattern' is ignored for the 'StatusCode' value
},
// 'Status' is the symbolic name of 'StatusCode'
"Status": {
"Publish": false,
"Name": "Status"
}
}
},
// The next object allows to configure 'Publish' and 'Pattern' for specific
// endpoint URLs. Those will overwrite the ones specified in the 'Defaults' object
// or the defaults used by publisher.
// It is not allowed to specify 'Name' and 'Flat' properties in this object.
"EndpointSpecific": [
// The following shows how a endpoint specific configuration can look like:
{
// 'ForEndpointUrl' allows to configure for which OPC UA server this
// object applies and is a required property for all objects in the
// 'EndpointSpecific' array.
// The value of 'ForEndpointUrl' must be an 'EndpointUrl' configured in
// the publishednodes.json confguration file.
"ForEndpointUrl": "opc.tcp://<your_opcua_server>:<your_opcua_server_port>/<your_opcua_server_path>",
"EndpointUrl": {
// We overwrite the default behaviour and publish the
// endpoint URL in this case.
"Publish": true,
// We are only interested in the URL part following the 'opc.tcp://' prefix
// and define a group matching this.
"Pattern": "opc.tcp://(.*)"
},
"NodeId": {
// We are not interested in the configured 'NodeId' value,
// so we do not publish it.
"Publish": false
// No 'Pattern' key is specified here, so the 'NodeId' value will be
// taken as specified in the publishednodes configuration file.
},
"MonitoredItem": {
"ApplicationUri": {
// We already publish the endpoint URL, so we do not want
// the ApplicationUri of the MonitoredItem to be published.
"Publish": false
},
"DisplayName": {
"Publish": true
}
},
"Value": {
"Value": {
// The value of the node is important for us, everything else we
// are not interested in to keep the data ingest as small as possible.
"Publish": true
},
"SourceTimestamp": {
"Publish": false
},
"StatusCode": {
"Publish": false
},
"Status": {
"Publish": false
}
}
}
]
}
Running the application
Command line options
The complete usage of the application can be shown using the --help command line option and is as follows:
Current directory is: /appdata
Log file is: <hostname>-publisher.log
Log level is: info
OPC Publisher V2.3.0
Informational version: V2.3.0+Branch.develop_hans_methodlog.Sha.0985e54f01a0b0d7f143b1248936022ea5d749f9
Usage: opcpublisher.exe <applicationname> [<iothubconnectionstring>] [<options>]
OPC Edge Publisher to subscribe to configured OPC UA servers and send telemetry to Azure IoTHub.
To exit the application, just press CTRL-C while it is running.
applicationname: the OPC UA application name to use, required
The application name is also used to register the publisher under this name in the
IoTHub device registry.
iothubconnectionstring: the IoTHub owner connectionstring, optional
There are a couple of environment variables which can be used to control the application:
_HUB_CS: sets the IoTHub owner connectionstring
_GW_LOGP: sets the filename of the log file to use
_TPC_SP: sets the path to store certificates of trusted stations
_GW_PNFP: sets the filename of the publishing configuration file
Command line arguments overrule environment variable settings.
Options:
--pf, --publishfile=VALUE
the filename to configure the nodes to publish.
Default: '/appdata/publishednodes.json'
--tc, --telemetryconfigfile=VALUE
the filename to configure the ingested telemetry
Default: ''
-s, --site=VALUE the site OPC Publisher is working in. if specified
this domain is appended (delimited by a ':' to
the 'ApplicationURI' property when telemetry is
sent to IoTHub.
The value must follow the syntactical rules of a
DNS hostname.
Default: not set
--ic, --iotcentral publisher will send OPC UA data in IoTCentral
compatible format (DisplayName of a node is used
as key, this key is the Field name in IoTCentral)
. you need to ensure that all DisplayName's are
unique. (Auto enables fetch display name)
Default: False
--sw, --sessionconnectwait=VALUE
specify the wait time in seconds publisher is
trying to connect to disconnected endpoints and
starts monitoring unmonitored items
Min: 10
Default: 10
--mq, --monitoreditemqueuecapacity=VALUE
specify how many notifications of monitored items
can be stored in the internal queue, if the data
can not be sent quick enough to IoTHub
Min: 1024
Default: 8192
--di, --diagnosticsinterval=VALUE
shows publisher diagnostic info at the specified
interval in seconds (need log level info).
-1 disables remote diagnostic log and diagnostic
output
0 disables diagnostic output
Default: 0
--ns, --noshutdown=VALUE
same as runforever.
Default: False
--rf, --runforever publisher can not be stopped by pressing a key on
the console, but will run forever.
Default: False
--lf, --logfile=VALUE the filename of the logfile to use.
Default: './<hostname>-publisher.log'
--lt, --logflushtimespan=VALUE
the timespan in seconds when the logfile should be
flushed.
Default: 00:00:30 sec
--ll, --loglevel=VALUE the loglevel to use (allowed: fatal, error, warn,
info, debug, verbose).
Default: info
--ih, --iothubprotocol=VALUE
the protocol to use for communication with IoTHub (
allowed values: Amqp, Http1, Amqp_WebSocket_Only,
Amqp_Tcp_Only, Mqtt, Mqtt_WebSocket_Only, Mqtt_
Tcp_Only) or IoT EdgeHub (allowed values: Mqtt_
Tcp_Only, Amqp_Tcp_Only).
Default for IoTHub: Mqtt_WebSocket_Only
Default for IoT EdgeHub: Amqp_Tcp_Only
--ms, --iothubmessagesize=VALUE
the max size of a message which can be send to
IoTHub. when telemetry of this size is available
it will be sent.
0 will enforce immediate send when telemetry is
available
Min: 0
Max: 262144
Default: 262144
--si, --iothubsendinterval=VALUE
the interval in seconds when telemetry should be
send to IoTHub. If 0, then only the
iothubmessagesize parameter controls when
telemetry is sent.
Default: '10'
--dc, --deviceconnectionstring=VALUE
if publisher is not able to register itself with
IoTHub, you can create a device with name <
applicationname> manually and pass in the
connectionstring of this device.
Default: none
-c, --connectionstring=VALUE
the IoTHub owner connectionstring.
Default: none
--hb, --heartbeatinterval=VALUE
the publisher is using this as default value in
seconds for the heartbeat interval setting of
nodes without
a heartbeat interval setting.
Default: 0
--sf, --skipfirstevent=VALUE
the publisher is using this as default value for
the skip first event setting of nodes without
a skip first event setting.
Default: False
--pn, --portnum=VALUE the server port of the publisher OPC server
endpoint.
Default: 62222
--pa, --path=VALUE the enpoint URL path part of the publisher OPC
server endpoint.
Default: '/UA/Publisher'
--lr, --ldsreginterval=VALUE
the LDS(-ME) registration interval in ms. If 0,
then the registration is disabled.
Default: 0
--ol, --opcmaxstringlen=VALUE
the max length of a string opc can transmit/
receive.
Default: 131072
--ot, --operationtimeout=VALUE
the operation timeout of the publisher OPC UA
client in ms.
Default: 120000
--oi, --opcsamplinginterval=VALUE
the publisher is using this as default value in
milliseconds to request the servers to sample
the nodes with this interval
this value might be revised by the OPC UA
servers to a supported sampling interval.
please check the OPC UA specification for
details how this is handled by the OPC UA stack.
a negative value will set the sampling interval
to the publishing interval of the subscription
this node is on.
0 will configure the OPC UA server to sample in
the highest possible resolution and should be
taken with care.
Default: 1000
--op, --opcpublishinginterval=VALUE
the publisher is using this as default value in
milliseconds for the publishing interval setting
of the subscriptions established to the OPC UA
servers.
please check the OPC UA specification for
details how this is handled by the OPC UA stack.
a value less than or equal zero will let the
server revise the publishing interval.
Default: 0
--ct, --createsessiontimeout=VALUE
specify the timeout in seconds used when creating
a session to an endpoint. On unsuccessful
connection attemps a backoff up to 5 times the
specified timeout value is used.
Min: 1
Default: 10
--ki, --keepaliveinterval=VALUE
specify the interval in seconds the publisher is
sending keep alive messages to the OPC servers
on the endpoints it is connected to.
Min: 2
Default: 2
--kt, --keepalivethreshold=VALUE
specify the number of keep alive packets a server
can miss, before the session is disconneced
Min: 1
Default: 5
--aa, --autoaccept the publisher trusts all servers it is
establishing a connection to.
Default: False
--tm, --trustmyself=VALUE
same as trustowncert.
Default: False
--to, --trustowncert the publisher certificate is put into the trusted
certificate store automatically.
Default: False
--fd, --fetchdisplayname=VALUE
same as fetchname.
Default: False
--fn, --fetchname enable to read the display name of a published
node from the server. this will increase the
runtime.
Default: False
--ss, --suppressedopcstatuscodes=VALUE
specifies the OPC UA status codes for which no
events should be generated.
Default: BadNoCommunication,
BadWaitingForInitialData
--at, --appcertstoretype=VALUE
the own application cert store type.
(allowed values: Directory, X509Store)
Default: 'Directory'
--ap, --appcertstorepath=VALUE
the path where the own application cert should be
stored
Default (depends on store type):
X509Store: 'CurrentUser\UA_MachineDefault'
Directory: 'pki/own'
--tp, --trustedcertstorepath=VALUE
the path of the trusted cert store
Default: 'pki/trusted'
--rp, --rejectedcertstorepath=VALUE
the path of the rejected cert store
Default 'pki/rejected'
--ip, --issuercertstorepath=VALUE
the path of the trusted issuer cert store
Default 'pki/issuer'
--csr show data to create a certificate signing request
Default 'False'
--ab, --applicationcertbase64=VALUE
update/set this applications certificate with the
certificate passed in as bas64 string
--af, --applicationcertfile=VALUE
update/set this applications certificate with the
certificate file specified
--pb, --privatekeybase64=VALUE
initial provisioning of the application
certificate (with a PEM or PFX fomat) requires a
private key passed in as base64 string
--pk, --privatekeyfile=VALUE
initial provisioning of the application
certificate (with a PEM or PFX fomat) requires a
private key passed in as file
--cp, --certpassword=VALUE
the optional password for the PEM or PFX or the
installed application certificate
--tb, --addtrustedcertbase64=VALUE
adds the certificate to the applications trusted
cert store passed in as base64 string (multiple
strings supported)
--tf, --addtrustedcertfile=VALUE
adds the certificate file(s) to the applications
trusted cert store passed in as base64 string (
multiple filenames supported)
--ib, --addissuercertbase64=VALUE
adds the specified issuer certificate to the
applications trusted issuer cert store passed in
as base64 string (multiple strings supported)
--if, --addissuercertfile=VALUE
adds the specified issuer certificate file(s) to
the applications trusted issuer cert store (
multiple filenames supported)
--rb, --updatecrlbase64=VALUE
update the CRL passed in as base64 string to the
corresponding cert store (trusted or trusted
issuer)
--uc, --updatecrlfile=VALUE
update the CRL passed in as file to the
corresponding cert store (trusted or trusted
issuer)
--rc, --removecert=VALUE
remove cert(s) with the given thumbprint(s) (
multiple thumbprints supported)
--dt, --devicecertstoretype=VALUE
the iothub device cert store type.
(allowed values: Directory, X509Store)
Default: X509Store
--dp, --devicecertstorepath=VALUE
the path of the iot device cert store
Default Default (depends on store type):
X509Store: 'My'
Directory: 'CertificateStores/IoTHub'
-i, --install register OPC Publisher with IoTHub and then exits.
Default: False
-h, --help show this message and exit
--st, --opcstacktracemask=VALUE
ignored, only supported for backward comaptibility.
--sd, --shopfloordomain=VALUE
same as site option, only there for backward
compatibility
The value must follow the syntactical rules of a
DNS hostname.
Default: not set
--vc, --verboseconsole=VALUE
ignored, only supported for backward comaptibility.
--as, --autotrustservercerts=VALUE
same as autoaccept, only supported for backward
cmpatibility.
Default: False
--tt, --trustedcertstoretype=VALUE
ignored, only supported for backward compatibility.
the trusted cert store will always reside in a
directory.
--rt, --rejectedcertstoretype=VALUE
ignored, only supported for backward compatibility.
the rejected cert store will always reside in a
directory.
--it, --issuercertstoretype=VALUE
ignored, only supported for backward compatibility.
the trusted issuer cert store will always
reside in a directory.
Typically you specify the IoTHub owner connectionstring only on the first start of the application. The connectionstring will be encrypted and stored in the platforms certificiate store. On subsequent calls it will be read from there and reused. If you specify the connectionstring on each start, the device which is created for the application in the IoTHub device registry will be removed and recreated each time.
Native on Windows
Open the opcpublisher.sln project with Visual Studio 2017, build the solution and publish it. You can start the application in the 'Target directory' you have published to with:
dotnet opcpublisher.dll <applicationname> [<iothubconnectionstring>] [options]
Using a self-built container
Build your own container and then start the container:
docker run <your-container-name> <applicationname> [<iothubconnectionstring>] [options]
Using a container from Microsoft Container Registry
There is a prebuilt container available on docker hub. To start it, just do:
docker run mcr.microsoft.com/iotedge/opc-publisher <applicationname> [<iothubconnectionstring>] [options]
Check docker Hub to see which operating systems and processor architectures are supported. The right container for your OS and CPU architecture (if supported) will be automatically selected and used.
Using it as a module in Azure IoT Edge
OPC Publisher is ready to be used as a module to run in Azure IoT Edge Microsoft's Intelligent Edge framework. We recommend to take a look on the information available on the beforementioned link and use then the information provided here. When using OPC Publisher as IoT Edge module only Amqp_Tcp_Only and Mqtt_Tcp_Only are supported as transport protocols.
To add OPC Publisher as module to your IoT Edge deployment, you go to the Azure portal and navigate to your IoTHub and:
-
Go to IoT Edge and create or select your IoT Edge device.
-
Select
Set Modules. -
Select
AddunderDeployment Modulesand thenIoT Edge Module. -
In the
Namefield, enterpublisher. -
In the
Image URIfield, entermcr.microsoft.com/iotedge/opc-publisher:<tag> -
The tags available can be found on docker Hub
-
Paste the following into the
Container Create Optionsfield:{ "Hostname": "publisher", "Cmd": [ "--aa" ] }This configuration will configure IoT Edge to start a container named
publisherwith OPC Publisher as the image. The hostname of the container's system will be set topublisher. OPC Publisher is called with the following command line:--aa. With this option OPC Publisher trusts those OPC UA server's certificates it is connecting to. You can use any options in theCmdarray OPC Publisher supports. The only limitation is the size of theContainer Create Optionssupported by IoT Edge. -
Leave the other settings unchanged and select
Save. -
If you want to process the output of the OPC Publisher locally with another Edge module, go back to the
Set Modulespage, and go to theSpecify Routestab and add a new route looking like (Notice the usage of the output for the OPC publisher):{ "routes": { "processingModuleToIoTHub": "FROM /messages/modules/processingModule/outputs/* INTO $upstream", "opcPublisherToProcessingModule": "FROM /messages/modules/publisher INTO BrokeredEndpoint(\"/modules/processingModule/inputs/input1\")" } -
Back in the
Set Modulespage, selectNext, till you reach the last page of the configuration. -
Select
Submitto send your configuration down to IoT Edge -
When you have started IoT Edge on your edge device and the docker container
publisheris started, you can check out the log output of OPC Publisher either by usingdocker logs -f publisheror by checking the logfile (in our example aboved:\iiotegde\publisher-publisher.logcontent or by using the diagnostic tool here.
Important when using a container
Access to the OPC Publisher OPC UA server
The OPC Publisher OPC UA server listens by default on port 62222. To expose this inbound port in a container, you need to use docker run option -p:
docker run -p 62222:62222 mcr.microsoft.com/iotedge/opc-publisher <applicationname> [<iothubconnectionstring>] [options]
Enable intercontainer nameresolution
To enable name resolution from within the container to other containers, you need to create a user define docker bridge network and connect the container to this network using the --network option.
Additionally you need to assign the container a name using the --name option as in this example:
docker network create -d bridge iot_edge
docker run --network iot_edge --name publisher mcr.microsoft.com/iotedge/opc-publisher <applicationname> [<iothubconnectionstring>] [options]
The container can now be reached by other containers via the name publisherover the network.
Access other systems from within the container
Other containers, can be reached using the parameters described in the "Enable intercontainer nameresolution" paragraph.
If operating system on which docker is hosted is DNS enabled, then accessing all systems which are known by DNS will work..
A problems occurs in a network which does use NetBIOS name resolution. To enable access to other systems (including the one on which docker is hosted) you need to start your container using the --add-host option,
which effectevly is adding an entry to the containers host file.
docker run --add-host mydevbox:192.168.178.23 mcr.microsoft.com/iotedge/opc-publisher <applicationname> [<iothubconnectionstring>] [options]
Assigning a hostname
OPC Publisher uses the hostname of the machine is running on for certificate and endpoint generation. docker chooses a random hostname if there is none set by the -h option. Here an example to set the internal hostname of the container to publisher:
docker run -h publisher mcr.microsoft.com/iotedge/opc-publisher <applicationname> [<iothubconnectionstring>] [options]
Using bind mounts (shared filesystem)
In certain use cases it may make sense to read configuration information from or write log files to locations on the host and not keep
them in the container file system only. To achieve this you need to use the -v option of docker run in the bind mount mode.
Using IoT Edge
The description in Using it as a module in Azure IoT Edge above is the simplest configuration. Very common is that you want to use the configuration files accessible in the host file system.
Here is a set of Container Create Optionswhich allow you to achieve this (be aware that the following example is of a deployment using Linux Containers for Windows):
{
"Hostname": "publisher",
"Cmd": [
"--pf=./pn.json",
"--aa"
],
"HostConfig": {
"Binds": [
"d:/iiotedge:/appdata"
]
}
}
With those options OPC Publisher will read the nodes it should publish from the file ./pn.json. The container's working directory is set to
/appdataat startup (see ./Dockerfile in the repository) and thus OPC Publisher will read the file /appdata/pn.json inside the container to get the configuration.
Without the --pf option, OPC Publisher will try to read its default configuration file ./publishednodes.json.
The log file publisher-publisher.log (default name) will be written to /appdata and the CertificateStores directory will also be created in this directory.
To make all those files available in the host file system the container configuration requires a bind mount volume.
The d://iiotedge:/appdata bind will map the directory /appdata (which is the current working directory on container startup) to the host directory d://iiotedge.
If this is not given, all file data will be not persisted when the container is started again.
If you are running Windows containers, then the syntax of the Bindsparameter is different. At container startup the working directory is c:\appdata.
That means you need to specify the following mapping in the HostConfig if you want to put the configuration file in the directory d:\iiotedgeon the host:
"HostConfig": {
"Binds": [
"d:/iiotedge:c:/appdata"
]
}
If you are running Linux containers on Linux, then the syntax of the Bindsparameter is again different. At container startup the working directory is /appdata.
That means if you specify the following mapping in the HostConfig, then the configuration file should reside in the directory /iiotedge on the host:
"HostConfig": {
"Binds": [
"/iiotedge:/appdata"
]
}
OPC UA X.509 certificates
As you know, OPC UA is using X.509 certificates to authenticate OPC UA client and server during establishment of a connection and
to encrypt the communication between the two parties.
OPC Publisher does use certificate stores maintained by the OPC UA stack to manage all certificates.
On startup OPC Publisher checks if there is a certificate for itself (see InitApplicationSecurityAsync
in OpcApplicationConfigurationSecurity.cs) and creates a self-signed certificate if there is none or if there is not one passed in
via command line options.
Self-signed certificates do not provide any security, since they are not signed by a trusted CA.
OPC Publisher does provide several command line options to:
- retrieve CSR information of the current application certificate used by OPC Publisher
- provision OPC Publisher with a CA signed certificate
- provision OPC Publisher with a new key pair and matching CA signed certificate
- add certificates to the trusted peer or trusted issuer cert store with certificates from an OPC UA application or from a CA
- add a CRL
- remove a certificate from the trusted peer or trusted issuers cert store
All these options allow to pass in parameters via files or base64 encoded strings.
The default store type for all cert stores is the file system. You can change that via command line options. Especially when you run OPC Publisher
in a container, then the persistency of the certificates is important, since the container does not provide persistency. You need to use docker's -v option
to persist the certificate stores in the host file system or a docker volume. If you are use a docker volume, you can pass in certificate relevant
data via base64 encoded strings.
If you want to see how a CA signed certificate can be used, please open an issue on this repo and we follow up.
You need to take special care how certificate stores are handled. Especially for the application certificate the runtime environment has impact and you want to make sure that it is persisted and not created new on each start:
- Running on Windows natively, you can not use an application certificate store of type
Directory, since the access to the private key fails. Please use the option--at X509Storein this case. - Running as Linux docker container, you can map the certificate stores to the host file system by using the docker run option
-v <hostdirectory>:/appdata. This will make the certificate persistent over starts. - Running as Linux docker container and want to use an X509Store for the application certificate, you need to use the docker run option
-v x509certstores:/root/.dotnet/corefx/cryptography/x509storesand the application option--at X509Store
Performance and memory considerations
Commandline parameters contolling performance and memory
When running OPC Publisher you need to be aware of your performance requirements and the memory resources you have available on your platform. Since both are interdependent and both depend on the configuration of how many nodes are configured to publish, you should ensure that the parameters you are using for:
- IoTHub send interval (
--si) - IoTHub message size (
--ms) - Monitored Items queue capacity (
--mq) do meet your requirements.
The --mq parameter controls the upper bound of the capacity of the internal queue, which buffers all notifications if a value of an OPC node changes. If OPC Publisher is not able to send messages to IoTHub fast enough,
then this queue buffers those notifications. The parameter sets the number of notifications which can be buffered. If you seen the number of items in this queue increasing in your test runs, you need to:
- decrease the IoTHub send interval (
--si) - increase the IoTHub message size (
--ms) otherwise you will loose the data values of those OPC node changes. The--mqparameter at the same time allows to prevent controlling the upper bound of the memory resources used by OPC Publisher.
The --si parameter enforces OPC Publisher to send messages to IoTHub as the specified interval. If there is an IoTHub message size specified via the --ms parameter (or by the default value for it),
then a message will be sent either when the message size is reached (in this case the interval is restarted) or when the specified interval time has passed. If you disable the message size by --ms 0, OPC Publisher
uses the maximal possible IoTHub message size of 256 kB to batch data.
The --ms parameter allows you to enable batching of messages sent to IoTHub. Depending on the protocol you are using, the overhead to send a message to IoTHub is high compared to the actual time of sending the payload.
If your scenario allows latency for the data ingested, you should configure OPC Publisher to use the maximal message size of 256 kB.
Before you use OPC Publisher in production scenarios, you need to test the performance and memory under production conditions. You can use the --di commandline parameter to specify a interval in seconds,
which will trigger the output of diagnostic information at this interval.
Test measurements
Here are some measurements with different values for --si and --ms parameters publishing 500 nodes with an OPC publishing interval of 1 second.
OPC Publisher was used as debug build on Windows 10 natively for 120 seconds. The IoTHub protocol was the default MQTT protocol.
Default configuration (--si 10 --ms 262144)
==========================================================================
OpcPublisher status @ 26.10.2017 15:33:05 (started @ 26.10.2017 15:31:09)
---------------------------------
OPC sessions: 1
connected OPC sessions: 1
connected OPC subscriptions: 5
OPC monitored items: 500
---------------------------------
monitored items queue bounded capacity: 8192
monitored items queue current items: 0
monitored item notifications enqueued: 54363
monitored item notifications enqueue failure: 0
monitored item notifications dequeued: 54363
---------------------------------
messages sent to IoTHub: 109
last successful msg sent @: 26.10.2017 15:33:04
bytes sent to IoTHub: 12709429
avg msg size: 116600
msg send failures: 0
messages too large to sent to IoTHub: 0
times we missed send interval: 0
---------------------------------
current working set in MB: 90
--si setting: 10
--ms setting: 262144
--ih setting: Mqtt
==========================================================================
The default configuration sends data to IoTHub each 10 seconds or when 256 kB of data to ingest is available. This adds a moderate latency of max 10 seconds, but has lowest probablilty of loosing data because of the large message size.
As you see in the diagnostics ouptut there are no OPC node udpates lost (monitored item notifications enqueue failure).
Constant send inverval (--si 1 --ms 0)
==========================================================================
OpcPublisher status @ 26.10.2017 15:35:59 (started @ 26.10.2017 15:34:03)
---------------------------------
OPC sessions: 1
connected OPC sessions: 1
connected OPC subscriptions: 5
OPC monitored items: 500
---------------------------------
monitored items queue bounded capacity: 8192
monitored items queue current items: 0
monitored item notifications enqueued: 54243
monitored item notifications enqueue failure: 0
monitored item notifications dequeued: 54243
---------------------------------
messages sent to IoTHub: 109
last successful msg sent @: 26.10.2017 15:35:59
bytes sent to IoTHub: 12683836
avg msg size: 116365
msg send failures: 0
messages too large to sent to IoTHub: 0
times we missed send interval: 0
---------------------------------
current working set in MB: 90
--si setting: 1
--ms setting: 0
--ih setting: Mqtt
==========================================================================
When the message size is set to 0 and there is a send interval configured (or the default of 1 second is used), then OPC Publisher does use internally batch data using the maximal supported IoTHub message size, which is 256 kB. As you see in the diagnostic output, the average message size is 115019 byte. In this configuration we do not loose any OPC node value udpates and compared to the default it adds lower latency.
Send each OPC node value update (--si 0 --ms 0)
==========================================================================
OpcPublisher status @ 26.10.2017 15:39:33 (started @ 26.10.2017 15:37:37)
---------------------------------
OPC sessions: 1
connected OPC sessions: 1
connected OPC subscriptions: 5
OPC monitored items: 500
---------------------------------
monitored items queue bounded capacity: 8192
monitored items queue current items: 8184
monitored item notifications enqueued: 54232
monitored item notifications enqueue failure: 44624
monitored item notifications dequeued: 1424
---------------------------------
messages sent to IoTHub: 1423
last successful msg sent @: 26.10.2017 15:39:33
bytes sent to IoTHub: 333046
avg msg size: 234
msg send failures: 0
messages too large to sent to IoTHub: 0
times we missed send interval: 0
---------------------------------
current working set in MB: 96
--si setting: 0
--ms setting: 0
--ih setting: Mqtt
==========================================================================
This configuration sends for each OPC node value change a message to IoTHub. You see the average message size of 234 byte is pretty small. The advantage of this configuration is that OPC Publisher does not add any latency to the ingest data path. The number of
lost OPC node value updates (monitored item notifications enqueue failure: 44624) is the highest of all compared configurations, which make this configuration not recommendable for use cases, when a lot of telemetry should be published.
Maximum batching (--si 0 --ms 262144)
==========================================================================
OpcPublisher status @ 26.10.2017 15:42:55 (started @ 26.10.2017 15:41:00)
---------------------------------
OPC sessions: 1
connected OPC sessions: 1
connected OPC subscriptions: 5
OPC monitored items: 500
---------------------------------
monitored items queue bounded capacity: 8192
monitored items queue current items: 0
monitored item notifications enqueued: 54137
monitored item notifications enqueue failure: 0
monitored item notifications dequeued: 54137
---------------------------------
messages sent to IoTHub: 48
last successful msg sent @: 26.10.2017 15:42:55
bytes sent to IoTHub: 12565544
avg msg size: 261782
msg send failures: 0
messages too large to sent to IoTHub: 0
times we missed send interval: 0
---------------------------------
current working set in MB: 90
--si setting: 0
--ms setting: 262144
--ih setting: Mqtt
==========================================================================
This configuration batches as much OPC node value udpates as possible. The maximum IoTHub message size is 256 kB, which is configured here. There is no send interval requested, which makes the time when data is ingested completely controlled by the data itself. This configuration has the least probability of loosing any OPC node values and can be used for publishing a high number of nodes. When using this configuration you need to ensure, that your scenario does not have conditions where high latency is introduced (because the message size of 256 kB is not reached).
Debugging the application
Native on Windows
Open the opcpublisher.sln project with Visual Studio 2017 and start debugging the app by hitting F5.
If you need to access the OPC UA server in the OPC Publisher, you should ensure that the firewall setting allow access to the port the server is listening on (default: 62222).
Controlling the application remotely
As already mentioned above the configuration of nodes to be published can be configured via IoTHub direct methods.
Beyond this OPC Publisher implements a few IoTHub direct method calls, which allow to read:
- general Information
- diagnostic information on OPC sessions, subscriptions and monitored items
- diagnostic information on IoTHub messages and events
- the startup log
- the last 100 lines of the log
In addition to this is implements a direct method to exit the application.
In the following github repos there are tools to configure the nodes to publish and read the diagnostic information. Both tools are also available as containers in Docker Hub.
As OPC UA server to start
If you do not have a real OPC UA server, you can use this sample OPC UA PLC to start. This sample PLC is also available on Docker Hub.
It implements a couple of tags, which generate random data and tags with anomalies and can be extended easily if you need to simulate any tag values.