This topic describes how to use Application Real-Time Monitoring Service (ARMS) SDKs to dynamically obtain a trace ID and the properties of the trace from the service code.
Prerequisites
- Your Java application is connected to ARMS. The ARMS agent for application monitoring is installed and started in the application. For more information, see Manually install an ARMS agent for a Java application.
- arms-sdk-1.7.3.jar is introduced to the application.
<dependency> <groupId>com.alibaba.arms.apm</groupId> <artifactId>arms-sdk</artifactId> <version>1.7.3</version> </dependency>
Note If you cannot obtain the dependency from the pom.xml file, download arms-sdk-1.7.3.jar.
Obtain a trace ID and an RPC ID
You can run the following code to obtain a trace ID and a remote procedure call (RPC) ID:
Span span = Tracer.builder().getSpan();
String traceId = span.getTraceId();
String rpcId = span.getRpcId();
Pass through custom baggage items
To pass through custom baggage items, you must perform the following steps to add the items to and obtain the items from the service code:
Add baggage items to the service code.
Map<String, String> baggage = new HashMap<String, String>(); baggage.put("key-01", "value-01"); baggage.put("key-02", "value-02"); baggage.put("key-03", "value-03"); Span span = Tracer.builder().getSpan(); span.withBaggage(baggage);
Obtain the baggage items from the service code.
Span span = Tracer.builder().getSpan(); Map<String, String> baggage = span.baggageItems();
Add custom tags to a span
You can add a custom tag only to the current span. You cannot pass a custom tag to other spans. To add custom tags to a span, perform the following steps to add the tags to and obtain the tags from the service code:
Add tags to a span in the service code. You can specify multiple tags.
Span span = Tracer.builder().getSpan(); // Add a tag to the Span. span.setTag("tag-key1", "tag-value1"); span.setTag("tag-key2", "tag-value2");
Obtain the tags from the service code.
Span span = Tracer.builder().getSpan(); // Inspect the Span's tags. Map<String, String> tags = span.tags();
Query traces based on baggage items and tags
You can use baggage items and tags that are added to a span to query traces.
- A baggage item can be passed to the downstream and is generally used to color business data. We do not recommend that you specify a large number of baggage items.
- A tag applies only to the current span. You can add multiple tags to a span.
- Log on to the ARMS console. In the left-side navigation pane, choose .
- On the Trace Query page, select a region in the top navigation bar, and then select a value from the Parameter type drop-down list. Enter a value in the Parameter value field, and click Add to query criteria.
- In the returned results, find the trace that you want to query and click the trace ID.
- On the Traces tab, move the pointer over the value in the Service column to view the tags and baggage items of the current span. baggage items are automatically added to the tags of the span.