System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) · 강의

수동 계측 모범 사례

관측 가능성 데이터를 세밀하게 제어하기 위해 수동 계측을 언제 어떻게 적용할지 이해합니다. 사용자 지정 속성으로 추적 정보를 보강하는 방법을 배웁니다.

수동 계측 모범 사례은(는) CoddyKit의 무료 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의입니다. 이것은 4개 중 2번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

Manual Instrumentation Intro

Welcome! In this lesson, we'll dive into manual instrumentation with OpenTelemetry. While auto-instrumentation is great for quick wins, manual control gives you precision.

Manual instrumentation allows you to record highly specific details about your application's internal operations. This is crucial for debugging complex business logic or custom components.

Why Manual Over Auto?

Auto-instrumentation automatically collects data from common libraries and frameworks. However, it can't know your unique application logic.

Custom Logic: Instrument specific functions or blocks of code.
Business Context: Add attributes relevant to your business domain.
Fine-Grained Control: Define exact span boundaries and relationships.
Missing Coverage: Cover areas where auto-instrumentation doesn't reach.

Creating Your First Span

A span represents a single operation within a trace. To create one manually, you need a Tracer, which is obtained from the OpenTelemetry SDK.

Here's how to start a new span. Remember to always end your spans!

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.SpanBuilder;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class ManualSpanDemo {
  public static void main(String[] args) {
    // Setup OpenTelemetry SDK (simplified for demo)
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    // Start a new span
    Span span = tracer.spanBuilder("MyCustomOperation").startSpan();

    try {
      System.out.println("Executing custom operation...");
      // Simulate work
      Thread.sleep(100);
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
    } finally {
      // Always end the span!
      span.end();
      System.out.println("Span ended.");
    }
  }
}

Activating Spans with Scope

For a span to be part of the current trace context (and for child spans to automatically link to it), it needs to be active. The best way to manage this is using a Scope with a try-with-resources statement.

This ensures the span is automatically set as active and ended when the block exits.

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.Scope;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class ActiveSpanDemo {
  public static void main(String[] args) {
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    Span parentSpan = tracer.spanBuilder("ParentOperation").startSpan();
    try (Scope parentScope = parentSpan.makeCurrent()) { // Parent span is active
      System.out.println("Parent operation started.");

      Span childSpan = tracer.spanBuilder("ChildOperation").startSpan(); // Automatically links to parent
      try (Scope childScope = childSpan.makeCurrent()) {
        System.out.println("Child operation executing...");
        Thread.sleep(50);
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
      } finally {
        childSpan.end();
        System.out.println("Child operation ended.");
      }

      Thread.sleep(50);
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
    } finally {
      parentSpan.end();
      System.out.println("Parent operation ended.");
    }
  }
}

Adding Custom Attributes

Attributes are key-value pairs that provide contextual information about a span. They are vital for making your traces searchable and understandable.

You can add attributes to a span using span.setAttribute(). Use descriptive keys and relevant values.

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.Scope;
import io.opentelemetry.api.common.AttributeKey;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class SpanAttributesDemo {
  public static void main(String[] args) {
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    Span span = tracer.spanBuilder("ProcessOrder").startSpan();
    try (Scope scope = span.makeCurrent()) {
      System.out.println("Processing order...");
      // Add attributes for order details
      span.setAttribute("order.id", "XYZ789");
      span.setAttribute("customer.email", "user@example.com");
      span.setAttribute(AttributeKey.longKey("item.count"), 3L);

      Thread.sleep(150);
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
    } finally {
      span.end();
      System.out.println("Order processed. Span ended with attributes.");
    }
  }
}

Recording Span Events

Events are timestamped messages associated with a span. They are useful for marking significant moments or logging specific actions that occur during the span's lifetime, without creating new child spans.

Think of them as mini-logs within your trace, adding more detail to a specific operation.

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.Scope;
import io.opentelemetry.api.common.Attributes;
import io.opentelemetry.api.common.AttributeKey;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class SpanEventsDemo {
  public static void main(String[] args) {
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    Span span = tracer.spanBuilder("UserLogin").startSpan();
    try (Scope scope = span.makeCurrent()) {
      System.out.println("User login initiated...");
      span.addEvent("AuthenticationStarted");

      Thread.sleep(80);
      // Add an event with attributes
      span.addEvent("DatabaseCheck", Attributes.of(
          AttributeKey.stringKey("db.query"), "SELECT * FROM users WHERE id=?"
      ));

      Thread.sleep(70);
      span.addEvent("AuthenticationSuccessful");

    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
    } finally {
      span.end();
      System.out.println("User login span ended with events.");
    }
  }
}

Handling Errors in Spans

It's crucial to mark spans as failed when an error occurs. This helps quickly identify problematic operations in your system.

You can set a span's status to ERROR and record the exception that caused the failure. This provides rich context for debugging.

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.StatusCode;
import io.opentelemetry.api.trace.Scope;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class SpanErrorDemo {
  public static void main(String[] args) {
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    Span span = tracer.spanBuilder("CriticalFunction").startSpan();
    try (Scope scope = span.makeCurrent()) {
      System.out.println("Executing critical function...");
      // Simulate an error condition
      if (Math.random() > 0.5) {
        throw new RuntimeException("Simulated critical failure!");
      }
      System.out.println("Critical function completed successfully.");

    } catch (Exception e) {
      System.out.println("Error caught: " + e.getMessage());
      span.setStatus(StatusCode.ERROR, "Function failed");
      span.recordException(e);
    } finally {
      span.end();
      System.out.println("Critical function span ended.");
    }
  }
}

Best Practices for Spans

To get the most out of manual instrumentation, follow these guidelines:

Granularity: Create spans for meaningful units of work, not every single line of code.
Meaningful Names: Use clear, low-cardinality names (e.g., user.login, db.query).
Rich Attributes: Add relevant business and technical context as attributes.
Always End Spans: Use try-with-resources or explicit span.end() in a finally block.
Avoid Over-instrumentation: Too many spans can add overhead. Focus on critical paths.

Linking Spans Explicitly

While makeCurrent() handles most parent-child linking, sometimes you need to explicitly link spans. This is common in asynchronous scenarios or when integrating with non-instrumented systems.

You can use SpanBuilder.setParent() or setNoParent() to control the parent-child relationship.

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.api.trace.SpanContext;
import io.opentelemetry.api.trace.SpanKind;
import io.opentelemetry.api.trace.TraceFlags;
import io.opentelemetry.api.trace.TraceState;
import io.opentelemetry.context.Context;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.OpenTelemetrySdk;
import io.opentelemetry.sdk.trace.SdkTracerProvider;

public class ExplicitLinkDemo {
  public static void main(String[] args) {
    SdkTracerProvider sdkTracerProvider = SdkTracerProvider.builder().build();
    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
        .setTracerProvider(sdkTracerProvider)
        .buildAndRegisterGlobal();

    Tracer tracer = openTelemetry.getTracer("my-app", "1.0.0");

    // Imagine a span from an external system, represented by its context
    SpanContext externalContext = SpanContext.create(
        "1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d", // Trace ID
        "0000000000000001", // Span ID
        TraceFlags.getDefault(), TraceState.getDefault()
    );

    // Create a new span that links to this external context
    Span linkedSpan = tracer.spanBuilder("ProcessingExternalMessage")
        .setParent(Context.current().with(Span.wrap(externalContext))) // Link to external context
        .setSpanKind(SpanKind.CONSUMER) // Indicate it's a message consumer
        .startSpan();

    try {
      System.out.println("Processing message from external system...");
      linkedSpan.setAttribute("message.id", "MSG-123");
      Thread.sleep(100);
    } catch (InterruptedException e) {
      Thread.currentThread().interrupt();
    } finally {
      linkedSpan.end();
      System.out.println("Linked span ended.");
    }
  }
}

Manual Instrumentation Check

You're implementing a new feature that calculates a user's loyalty points. You want to instrument this specific calculation to track its duration and the final points awarded. Which of the following is the most appropriate way to record the final points using manual OpenTelemetry instrumentation?

Recap: Manual Control

In this lesson, we explored manual instrumentation with OpenTelemetry. You learned:

When to choose manual over auto-instrumentation for fine-grained control.
How to create, activate, and end spans.
The power of attributes for adding rich context to your traces.
How to use events to mark specific moments within a span.
Best practices for handling errors and linking spans explicitly.

Mastering manual instrumentation gives you unparalleled visibility into your application's unique logic and performance.

자주 묻는 질문

“수동 계측 모범 사례” 강의는 무료인가요?

네 — “수동 계측 모범 사례” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의 전체를 잠금 해제할 수 있습니다. System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의에는 총 4개의 강의가 포함되어 있습니다.

“수동 계측 모범 사례”에서 뭘 배우나요?

관측 가능성 데이터를 세밀하게 제어하기 위해 수동 계측을 언제 어떻게 적용할지 이해합니다. 사용자 지정 속성으로 추적 정보를 보강하는 방법을 배웁니다. 브라우저에서 직접 실행하는 실습 코드로 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry)을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry)을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry)은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 2번째 강의입니다.

“수동 계측 모범 사례” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 System Observability: Logging, Metrics & Tracing (ELK + OpenTelemetry) 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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