Enabling distributed tracing in microservices with Jaeger

 1// tag::copyright[]
 2/*******************************************************************************
 3 * Copyright (c) 2017, 2023 IBM Corporation and others.
 4 * All rights reserved. This program and the accompanying materials
 5 * are made available under the terms of the Eclipse Public License 2.0
 6 * which accompanies this distribution, and is available at
 7 * http://www.eclipse.org/legal/epl-2.0/
 8 *
 9 * SPDX-License-Identifier: EPL-2.0
10 *******************************************************************************/
11// end::copyright[]
12package io.openliberty.guides.inventory;
13
14import java.util.Properties;
15
16import org.eclipse.microprofile.opentracing.Traced;
17
18import io.openliberty.guides.inventory.model.InventoryList;
19import jakarta.enterprise.context.RequestScoped;
20import jakarta.inject.Inject;
21import jakarta.ws.rs.DELETE;
22import jakarta.ws.rs.GET;
23import jakarta.ws.rs.Path;
24import jakarta.ws.rs.PathParam;
25import jakarta.ws.rs.Produces;
26import jakarta.ws.rs.core.MediaType;
27import jakarta.ws.rs.core.Response;
28
29@RequestScoped
30@Path("/systems")
31// tag::InventoryResource[]
32public class InventoryResource {
33
34    @Inject InventoryManager manager;
35
36    @GET
37    @Path("/{hostname}")
38    @Produces(MediaType.APPLICATION_JSON)
39    // tag::getPropertiesForHost[]
40    public Response getPropertiesForHost(@PathParam("hostname") String hostname) {
41        Properties props = manager.get(hostname);
42        if (props == null) {
43            return Response.status(Response.Status.NOT_FOUND)
44                           .entity("{ \"error\" : \"Unknown hostname or the system "
45                           + "service may not be running on " + hostname + "\" }")
46                           .build();
47        }
48        manager.add(hostname, props);
49        return Response.ok(props).build();
50    }
51    // end::getPropertiesForHost[]
52
53    @GET
54    // tag::Traced-false[]
55    @Traced(false)
56    // end::Traced-false[]
57    @Produces(MediaType.APPLICATION_JSON)
58    // tag::listContents[]
59    public InventoryList listContents() {
60        return manager.list();
61    }
62    // end::listContents[]
63
64    @DELETE
65    @Produces(MediaType.APPLICATION_JSON)
66    public Response clearContents() {
67        int cleared = manager.clear();
68
69        if (cleared == 0) {
70            return Response.status(Response.Status.NOT_MODIFIED)
71                    .build();
72        }
73        return Response.status(Response.Status.OK)
74                .build();
75    }
76}
77// end::InventoryResource[]

 1// tag::copyright[]
 2/*******************************************************************************
 3 * Copyright (c) 2017, 2023 IBM Corporation and others.
 4 * All rights reserved. This program and the accompanying materials
 5 * are made available under the terms of the Eclipse Public License 2.0
 6 * which accompanies this distribution, and is available at
 7 * http://www.eclipse.org/legal/epl-2.0/
 8 *
 9 * SPDX-License-Identifier: EPL-2.0
10 *******************************************************************************/
11// end::copyright[]
12package io.openliberty.guides.inventory;
13
14import java.util.ArrayList;
15import java.util.Properties;
16import io.openliberty.guides.inventory.client.SystemClient;
17import io.openliberty.guides.inventory.model.InventoryList;
18import io.openliberty.guides.inventory.model.SystemData;
19import jakarta.enterprise.context.ApplicationScoped;
20import jakarta.inject.Inject;
21import java.util.List;
22import java.util.Collections;
23
24import org.eclipse.microprofile.config.inject.ConfigProperty;
25import org.eclipse.microprofile.opentracing.Traced;
26import io.opentracing.Scope;
27import io.opentracing.Tracer;
28import io.opentracing.Span;
29
30@ApplicationScoped
31// tag::InventoryManager[]
32public class InventoryManager {
33
34    @Inject
35    @ConfigProperty(name = "system.http.port")
36    int SYSTEM_PORT;
37
38    private List<SystemData> systems = Collections.synchronizedList(new ArrayList<>());
39    private SystemClient systemClient = new SystemClient();
40    // tag::customTracer[]
41    @Inject Tracer tracer;
42    // end::customTracer[]
43
44    public Properties get(String hostname) {
45        systemClient.init(hostname, SYSTEM_PORT);
46        Properties properties = systemClient.getProperties();
47        return properties;
48    }
49
50    public void add(String hostname, Properties systemProps) {
51        Properties props = new Properties();
52        props.setProperty("os.name", systemProps.getProperty("os.name"));
53        props.setProperty("user.name", systemProps.getProperty("user.name"));
54
55        SystemData system = new SystemData(hostname, props);
56        // tag::Add[]
57        if (!systems.contains(system)) {
58            // tag::addSpan[]
59            Span span = tracer.buildSpan("add() Span").start();
60            // end::addSpan[]
61            // tag::Try[]
62            try (Scope childScope = tracer.activateSpan(span)) {
63                // tag::addToInvList[]
64                systems.add(system);
65                // end::addToInvList[]
66            } finally {
67                span.finish();
68            }
69            // end::Try[]
70        }
71        // end::Add[]
72    }
73
74    // tag::Traced[]
75    @Traced(operationName = "InventoryManager.list")
76    // end::Traced[]
77    // tag::list[]
78    public InventoryList list() {
79        return new InventoryList(systems);
80    }
81    // end::list[]
82
83    int clear() {
84        int propertiesClearedCount = systems.size();
85        systems.clear();
86        return propertiesClearedCount;
87    }
88}
89// end::InventoryManager[]

 1// tag::copyright[]
 2/*******************************************************************************
 3 * Copyright (c) 2017, 2023 IBM Corporation and others.
 4 * All rights reserved. This program and the accompanying materials
 5 * are made available under the terms of the Eclipse Public License 2.0
 6 * which accompanies this distribution, and is available at
 7 * http://www.eclipse.org/legal/epl-2.0/
 8 *
 9 * SPDX-License-Identifier: EPL-2.0
10 *******************************************************************************/
11// end::copyright[]
12package io.openliberty.guides.system;
13
14import java.util.Properties;
15
16// CDI
17import jakarta.enterprise.context.RequestScoped;
18import jakarta.ws.rs.GET;
19// JAX-RS
20import jakarta.ws.rs.Path;
21import jakarta.ws.rs.Produces;
22import jakarta.ws.rs.core.MediaType;
23
24@RequestScoped
25@Path("properties")
26public class SystemResource {
27
28  @GET
29  @Produces(MediaType.APPLICATION_JSON)
30  // tag::Properties[]
31  public Properties getProperties() {
32    return System.getProperties();
33  }
34  // end::Properties[]
35}

 1// tag::copyright[]
 2/*******************************************************************************
 3 * Copyright (c) 2017, 2023 IBM Corporation and others.
 4 * All rights reserved. This program and the accompanying materials
 5 * are made available under the terms of the Eclipse Public License 2.0
 6 * which accompanies this distribution, and is available at
 7 * http://www.eclipse.org/legal/epl-2.0/
 8 *
 9 * SPDX-License-Identifier: EPL-2.0
10 *******************************************************************************/
11// end::copyright[]
12package io.openliberty.guides.inventory;
13
14import java.util.Properties;
15
16import org.eclipse.microprofile.opentracing.Traced;
17
18import io.openliberty.guides.inventory.model.InventoryList;
19import jakarta.enterprise.context.RequestScoped;
20import jakarta.inject.Inject;
21import jakarta.ws.rs.DELETE;
22import jakarta.ws.rs.GET;
23import jakarta.ws.rs.Path;
24import jakarta.ws.rs.PathParam;
25import jakarta.ws.rs.Produces;
26import jakarta.ws.rs.core.MediaType;
27import jakarta.ws.rs.core.Response;
28
29@RequestScoped
30@Path("/systems")
31// tag::InventoryResource[]
32public class InventoryResource {
33
34    @Inject InventoryManager manager;
35
36    @GET
37    @Path("/{hostname}")
38    @Produces(MediaType.APPLICATION_JSON)
39    // tag::getPropertiesForHost[]
40    public Response getPropertiesForHost(@PathParam("hostname") String hostname) {
41        Properties props = manager.get(hostname);
42        if (props == null) {
43            return Response.status(Response.Status.NOT_FOUND)
44                           .entity("{ \"error\" : \"Unknown hostname or the system "
45                           + "service may not be running on " + hostname + "\" }")
46                           .build();
47        }
48        manager.add(hostname, props);
49        return Response.ok(props).build();
50    }
51    // end::getPropertiesForHost[]
52
53    @GET
54    // tag::Traced-false[]
55    @Traced(false)
56    // end::Traced-false[]
57    @Produces(MediaType.APPLICATION_JSON)
58    // tag::listContents[]
59    public InventoryList listContents() {
60        return manager.list();
61    }
62    // end::listContents[]
63
64    @DELETE
65    @Produces(MediaType.APPLICATION_JSON)
66    public Response clearContents() {
67        int cleared = manager.clear();
68
69        if (cleared == 0) {
70            return Response.status(Response.Status.NOT_MODIFIED)
71                    .build();
72        }
73        return Response.status(Response.Status.OK)
74                .build();
75    }
76}
77// end::InventoryResource[]