NATS Endpoint
Use the NATS endpoint when the workflow moves through NATS subjects. This page explains how to publish, consume, authenticate, and keep tracking consistent.
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What this page helps you do
What this page helps you do
Use the NATS endpoint when the workflow moves through NATS subjects. This page explains how to publish, consume, authenticate, and keep tracking consistent.
Who this is for
Teams defining the transport-specific source or destination side of a correlated transaction.
Prerequisites
- A stable tracking field shared between the producer side and the consumer or completion side
By the end
A transport definition that matches the transaction you need to measure.
Use this page when
Use this page when NATS Endpoint is the source or destination side of the transaction and you need the documented endpoint fields before wiring the scenario.
Visual guide
Guide
Core Fields
Configure ServerUrl, Subject, and Mode first. QueueGroup is optional when consumers should share work, and ConnectionName helps trace NATS connections in broker diagnostics.
Authentication
Use UserName plus Password for basic auth or Token for token-based auth. Validation blocks invalid combinations so credentials stay explicit and transport-safe.
Tracking Extraction
TrackingField and GatherByField use the same `header:` or `json:` selector contract as other endpoints. The selector prefix is case-insensitive, but header names and JSON path segments are exact-case. Headers are preserved on produce, and message body parsing supports MessagePayloadType, JsonSettings, and JsonConvertSettings.
Connection Behavior
MaxReconnectAttempts lets you cap reconnect behavior for long-running produce or consume flows while keeping the endpoint contract aligned with the rest of the cross-platform runtime.
Endpoint definition samples
Use these samples to see how NATS Endpoint is represented as a source or destination endpoint before you attach it to a correlated scenario.
If you run these examples locally, add a valid runner key before execution starts. Set it with WithRunnerKey("...") or the config key LoadStrike:RunnerKey.
NATS Endpoint
using LoadStrike;
var tracking = new CrossPlatformTrackingConfiguration
{
Source = new HttpEndpointDefinition
{
Name = "orders-api",
Mode = TrafficEndpointMode.Produce,
TrackingField = TrackingFieldSelector.Parse("header:X-Correlation-Id"),
Url = "https://api.example.com/orders",
Method = "POST",
MessageHeaders = { ["X-Correlation-Id"] = "ord-1001" },
MessagePayload = new { orderId = "ord-1001", amount = 49.95m }
},
Destination = new NatsEndpointDefinition
{
Name = "nats-out",
Mode = TrafficEndpointMode.Consume,
TrackingField = TrackingFieldSelector.Parse("header:X-Correlation-Id"),
ServerUrl = "nats://localhost:4222",
Subject = "orders.completed",
QueueGroup = "loadstrike-orders",
ConnectionName = "orders-consumer"
}
};
var scenario = CrossPlatformScenarioConfigurator
.Configure(LoadStrikeScenario.Empty("orders-http-to-nats"), tracking)
.WithLoadSimulations(LoadStrikeSimulation.Inject(10, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(20)));
LoadStrikeRunner.RegisterScenarios(scenario)
.WithRunnerKey("rkl_your_local_runner_key")
.Run();package main
import loadstrike "loadstrike.com/sdk/go"
var natsEndpoint = &loadstrike.EndpointSpec{
Kind: "Nats",
Name: "orders-subject",
Mode: "Consume",
TrackingField: "header:X-Correlation-Id",
NATS: &loadstrike.NATSEndpointOptions{
ServerURL: "nats://127.0.0.1:4222",
Subject: "orders.completed",
QueueGroup: "orders-tests",
ConnectionName: "loadstrike-orders",
},
}import com.loadstrike.runtime.CrossPlatformScenarioConfigurator;
import com.loadstrike.runtime.CrossPlatformTrackingConfiguration;
import com.loadstrike.runtime.HttpEndpointDefinition;
import com.loadstrike.runtime.LoadStrikeCorrelation.TrackingFieldSelector;
import com.loadstrike.runtime.LoadStrikeRuntime.LoadStrikeRunner;
import com.loadstrike.runtime.LoadStrikeRuntime.LoadStrikeScenario;
import com.loadstrike.runtime.LoadStrikeRuntime.LoadStrikeSimulation;
import com.loadstrike.runtime.LoadStrikeTransports;
import com.loadstrike.runtime.NatsEndpointDefinition;
var source = new HttpEndpointDefinition();
source.name = "orders-api";
source.mode = LoadStrikeTransports.TrafficEndpointMode.Produce;
source.trackingField = TrackingFieldSelector.parse("header:X-Correlation-Id");
source.url = "https://api.example.com/orders";
source.method = "POST";
source.messageHeaders.put("X-Correlation-Id", "ord-1001");
source.messagePayload = java.util.Map.of("orderId", "ord-1001", "amount", 49.95);
var destination = new NatsEndpointDefinition();
destination.name = "nats-out";
destination.mode = LoadStrikeTransports.TrafficEndpointMode.Consume;
destination.trackingField = TrackingFieldSelector.parse("header:X-Correlation-Id");
destination.serverUrl = "nats://localhost:4222";
destination.subject = "orders.completed";
destination.queueGroup = "loadstrike-orders";
destination.connectionName = "orders-consumer";
var tracking = new CrossPlatformTrackingConfiguration();
tracking.source = source;
tracking.destination = destination;
var scenario = CrossPlatformScenarioConfigurator.Configure(
LoadStrikeScenario.empty("orders-http-to-nats"),
tracking
).withLoadSimulations(LoadStrikeSimulation.inject(10, 1d, 20d));
LoadStrikeRunner
.registerScenarios(scenario)
.withRunnerKey("rkl_your_local_runner_key")
.run();from loadstrike_sdk import CrossPlatformScenarioConfigurator, LoadStrikeRunner, LoadStrikeScenario, LoadStrikeSimulation
tracking = {
"Source": {
"Kind": "Http",
"Name": "orders-api",
"Mode": "Produce",
"TrackingField": "header:X-Correlation-Id",
"Url": "https://api.example.com/orders",
"Method": "POST",
"MessageHeaders": {"X-Correlation-Id": "ord-1001"},
"MessagePayload": {"orderId": "ord-1001", "amount": 49.95},
},
"Destination": {
"Kind": "Nats",
"Name": "nats-out",
"Mode": "Consume",
"TrackingField": "header:X-Correlation-Id",
"ServerUrl": "nats://localhost:4222",
"Subject": "orders.completed",
"QueueGroup": "loadstrike-orders",
"ConnectionName": "orders-consumer",
},
}
scenario = (
CrossPlatformScenarioConfigurator.Configure(
LoadStrikeScenario.empty("orders-http-to-nats"),
tracking,
)
.with_load_simulations(LoadStrikeSimulation.inject(10, 1, 20))
)
LoadStrikeRunner.register_scenarios(scenario) \
.with_runner_key("rkl_your_local_runner_key") \
.run()import {
CrossPlatformScenarioConfigurator,
LoadStrikeRunner,
LoadStrikeScenario,
LoadStrikeSimulation,
TrackingFieldSelector
} from "@loadstrike/loadstrike-sdk";
const tracking = {
Source: {
Kind: "Http",
Name: "orders-api",
Mode: "Produce",
TrackingField: new TrackingFieldSelector("Header", "X-Correlation-Id"),
Url: "https://api.example.com/orders",
Method: "POST",
MessageHeaders: { "X-Correlation-Id": "ord-1001" },
MessagePayload: { orderId: "ord-1001", amount: 49.95 }
},
Destination: {
Kind: "Nats",
Name: "nats-out",
Mode: "Consume",
TrackingField: new TrackingFieldSelector("Header", "X-Correlation-Id"),
ServerUrl: "nats://localhost:4222",
Subject: "orders.completed",
QueueGroup: "loadstrike-orders",
ConnectionName: "orders-consumer"
}
};
const scenario = CrossPlatformScenarioConfigurator
.Configure(LoadStrikeScenario.empty("orders-http-to-nats"), tracking)
.withLoadSimulations(LoadStrikeSimulation.inject(10, 1, 20));
await LoadStrikeRunner
.registerScenarios(scenario)
.withRunnerKey("rkl_your_local_runner_key")
.run();const {
CrossPlatformScenarioConfigurator,
LoadStrikeRunner,
LoadStrikeScenario,
LoadStrikeSimulation,
TrackingFieldSelector
} = require("@loadstrike/loadstrike-sdk");
(async () => {
const tracking = {
Source: {
Kind: "Http",
Name: "orders-api",
Mode: "Produce",
TrackingField: new TrackingFieldSelector("Header", "X-Correlation-Id"),
Url: "https://api.example.com/orders",
Method: "POST",
MessageHeaders: { "X-Correlation-Id": "ord-1001" },
MessagePayload: { orderId: "ord-1001", amount: 49.95 }
},
Destination: {
Kind: "Nats",
Name: "nats-out",
Mode: "Consume",
TrackingField: new TrackingFieldSelector("Header", "X-Correlation-Id"),
ServerUrl: "nats://localhost:4222",
Subject: "orders.completed",
QueueGroup: "loadstrike-orders",
ConnectionName: "orders-consumer"
}
};
const scenario = CrossPlatformScenarioConfigurator
.Configure(LoadStrikeScenario.empty("orders-http-to-nats"), tracking)
.withLoadSimulations(LoadStrikeSimulation.inject(10, 1, 20));
await LoadStrikeRunner
.registerScenarios(scenario)
.withRunnerKey("rkl_your_local_runner_key")
.run();
})();NATS endpoint fields and parameters
Required endpoint identifier. It appears in correlation tables, sink exports, and troubleshooting messages, so choose a stable descriptive name.
Choose Produce when LoadStrike should create traffic, or Consume when it should listen for downstream traffic. Run mode validation checks that the selected mode matches the source or destination role.
Selector that extracts the correlation id from a header or JSON body. It is normally required, but can be omitted when UseLoadStrikeTraceIdHeader is true so LoadStrike uses header:loadstrike-trace-id for generated source traffic. Selector prefixes such as header: and json: are parsed case-insensitively, but the header name or JSON path segments after the prefix must match exact casing. The extracted value is matched case-sensitively by default unless TrackingFieldValueCaseSensitive is turned off on the tracking configuration.
Optional destination-only selector used for grouped correlation reports. It follows the same selector-casing rules as TrackingField. Group values are grouped case-sensitively by default unless GatherByFieldValueCaseSensitive is turned off on the tracking configuration.
Defaults to true. When the source payload does not already contain the tracked id, LoadStrike can inject one so the generated traffic still produces a correlation key.
Defaults to false. When true and TrackingField is omitted, produced source messages receive a loadstrike-trace-id header with a GUID value. Consume-mode source endpoints and CorrelateExistingTraffic runs do not inject this header; they only observe it if the existing traffic already contains it.
Controls how often a consumer-style endpoint polls for new messages. The value must stay greater than zero whenever you set it explicitly.
Optional headers that are written with produced traffic and also influence tracking extraction when the selector targets headers. Header names are preserved exactly as you set them, and header selectors later match using that same exact casing.
Optional object or body value sent by producer-style endpoints. This is the payload your scenario is actually placing on the wire.
Optional type hint used when JSON selectors need typed parsing. Leave it unset when dynamic JSON parsing is enough.
Optional serializer settings for System.Text.Json or Newtonsoft.Json. Use them only when the payload shape or naming strategy requires custom parsing behavior.
Optional explicit content type for custom payload handling. This is most helpful for delegate-style transports or non-default HTTP body shapes.
Required NATS server or cluster URL.
Required NATS subject used for produce or consume mode.
Optional queue group for shared-consumer behavior. Use it only when multiple NATS consumers should split work from the same subject.
Optional username/password credentials. If UserName is set, Password must also be provided.
Optional token-based authentication field when the server uses token auth instead of user/password.
Optional descriptive name that makes the connection easier to identify on the broker side.
Reconnect budget for the NATS client. Zero means no reconnect attempts, and negative values are rejected.
{ "trackingId": "trk-1", "tenantId": "tenant-a" }