Debugging inside CDN-in-a-Box

Tip

For the purposes of development, it may be easier to use The Development Environment.

Some CDN-in-a-Box components can be used with a debugger to step through lines of code, set breakpoints, see the state of all variables in each scope, etc. at runtime. Components that support debugging:

Enroller
t3c on Caches
Traffic Monitor
Traffic Ops
Traffic Router
Traffic Stats

Enroller

In infrastructure/cdn-in-a-box, open variables.env and set ENROLLER_DEBUG_ENABLE to true.
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build/rebuild the enroller-debug image each time you have changed infrastructure/cdn-in-a-box/enroller/enroller.go. Then, start CDN-in-a-Box.
#95 docker compose command for debugging the CDN in a Box Enroller
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build enroller mydc up

Install an IDE that supports delve and create a debugging configuration over port 2343. If you are using VS Code, the configuration should look like this:

#96 VS Code launch.json for debugging the CDN in a Box Enroller

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Enroller",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2343,
            "cwd": "${workspaceRoot}/",
            "remotePath": "/go/src/github.com/apache/trafficcontrol/",
        }
    ]
}

Use the debugging configuration you created to start debugging the Enroller. It should connect without first breaking at any line.

For an example of usage, set a breakpoint at the toSession.CreateDeliveryServiceV30() call in enrollDeliveryService(), then wait for the Enroller to process a file from /shared/enroller/deliveryservices/ (only exists within the Docker container).

t3c on Caches

t3c on Edge Cache

Navigate to the infrastructure/cdn-in-a-box directory. Remove infrastructure/cdn-in-a-box/cache/trafficcontrol-cache-config.rpm because it contains release Go binaries that do not include useful debugging information. Rebuild the RPM with no optimization, for debugging:
#97 Remove release RPMs, then build debug RPMs
make very-clean make debug cache/trafficcontrol-cache-config.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native cache/trafficcontrol-cache-config.rpm instead of make debug cache/trafficcontrol-cache-config.rpm to build the RPM quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set T3C_DEBUG_COMPONENT_EDGE to t3c-apply (used for this example). A list of valid values for T3C_DEBUG_COMPONENT_EDGE:
- t3c-apply
- t3c-check
- t3c-check-refs
- t3c-check-reload
- t3c-diff
- t3c-generate
- t3c-request
- t3c-update
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the edge-debug image to make sure it uses our fresh trafficcontrol-cache-config.rpm. Then, start CDN-in-a-Box:
#98 docker compose command for debugging t3c running on the Edge Cache
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build edge mydc up -d mydc logs -f trafficmonitor

Install an IDE that supports delve and create a debugging configuration over port 2347. If you are using VS Code, the configuration should look like this:

#99 VS Code launch.json for debugging t3c on the Edge Cache

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "t3c on Edge",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2347,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Wait for Traffic Monitor to start, which will indicate that the SSL keys have been generated. Because T3C_DEBUG_COMPONENT_EDGE is set to the name of one of the t3c binaries, t3c will not run automatically every minute. Start it it manually:

#100 Run t3c-apply with debugging enabled

[user@computer cdn-in-a-box]$ mydc exec edge t3c apply --run-mode=badass --traffic-ops-url=https://trafficops.infra.ciab.test --traffic-ops-user=admin --traffic-ops-password=twelve12 --git=yes --dispersion=0 --log-location-error=stdout --log-location-warning=stdout --log-location-info=stdout all
API server listening at: [::]:2347

The API server listening message is from dlv, indicating it is ready to accept a connection from your IDE. Note that, unlike the other components, execution of t3c does not begin until your IDE connects to dlv.

For this example, set a breakpoint at the assignment of “##OVERRIDDEN## “ + str to newstr in torequest.processRemapOverrides().

Use the debugging configuration you created to connect to dlv and start debugging t3c.

t3c on Mid 01 Cache

Navigate to the infrastructure/cdn-in-a-box directory. Remove infrastructure/cdn-in-a-box/cache/trafficcontrol-cache-config.rpm because it contains release Go binaries that do not include useful debugging information. Rebuild the RPM with no optimization, for debugging:
#101 Remove release RPMs, then build debug RPMs
make very-clean make debug cache/trafficcontrol-cache-config.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native cache/trafficcontrol-cache-config.rpm instead of make debug cache/trafficcontrol-cache-config.rpm to build the RPM quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set T3C_DEBUG_COMPONENT_MID_01 to t3c-apply (used for this example). A list of valid values for T3C_DEBUG_COMPONENT_MID_01:
- t3c-apply
- t3c-check
- t3c-check-refs
- t3c-check-reload
- t3c-diff
- t3c-generate
- t3c-request
- t3c-update
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the mid-debug image to make sure it uses our fresh trafficcontrol-cache-config.rpm. Then, start CDN-in-a-Box:
#102 docker compose command for debugging t3c running on the Mid 01 Cache
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build mid-01 mydc up -d mydc logs -f trafficmonitor

Install an IDE that supports delve and create a debugging configuration over port 2348. If you are using VS Code, the configuration should look like this:

#103 VS Code launch.json for debugging t3c on the Mid 01 Cache

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "t3c on Mid 01",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2348,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Wait for Traffic Monitor to start, which will indicate that the SSL keys have been generated. Because T3C_DEBUG_COMPONENT_MID_01 is set to the name of one of the t3c binaries, t3c will not run automatically every minute. Start it it manually:

#104 Run t3c-apply with debugging enabled

[user@computer cdn-in-a-box]$ mydc exec mid-01 t3c apply --run-mode=badass --traffic-ops-url=https://trafficops.infra.ciab.test --traffic-ops-user=admin --traffic-ops-password=twelve12 --git=yes --dispersion=0 --log-location-error=stdout --log-location-warning=stdout --log-location-info=stdout all
API server listening at: [::]:2348

The API server listening message is from dlv, indicating it is ready to accept a connection from your IDE. Note that, unlike the other components, execution of t3c does not begin until your IDE connects to dlv.

For this example, set a breakpoint at the assignment of “##OVERRIDDEN## “ + str to newstr in torequest.processRemapOverrides().

Use the debugging configuration you created to connect to dlv and start debugging t3c.

t3c on Mid 02 Cache

Navigate to the infrastructure/cdn-in-a-box directory. Remove infrastructure/cdn-in-a-box/cache/trafficcontrol-cache-config.rpm because it contains release Go binaries that do not include useful debugging information. Rebuild the RPM with no optimization, for debugging:
#105 Remove release RPMs, then build debug RPMs
make very-clean make debug cache/trafficcontrol-cache-config.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native cache/trafficcontrol-cache-config.rpm instead of make debug cache/trafficcontrol-cache-config.rpm to build the RPM quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set T3C_DEBUG_COMPONENT_MID_02 to t3c-apply (used for this example). A list of valid values for T3C_DEBUG_COMPONENT_MID_02:
- t3c-apply
- t3c-check
- t3c-check-refs
- t3c-check-reload
- t3c-diff
- t3c-generate
- t3c-request
- t3c-update
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the mid-debug image to make sure it uses our fresh trafficcontrol-cache-config.rpm. Then, start CDN-in-a-Box:
#106 docker compose command for debugging t3c running on the Mid 02 Cache
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build mid-02 mydc up -d mydc logs -f trafficmonitor

Install an IDE that supports delve and create a debugging configuration over port 2349. If you are using VS Code, the configuration should look like this:

#107 VS Code launch.json for debugging t3c on the Mid 02 Cache

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "t3c on Mid 02",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2349,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Wait for Traffic Monitor to start, which will indicate that the SSL keys have been generated. Because T3C_DEBUG_COMPONENT_MID_02 is set to the name of one of the t3c binaries, t3c will not run automatically every minute. Start it it manually:

#108 Run t3c-apply with debugging enabled

[user@computer cdn-in-a-box]$ mydc exec mid-02 t3c apply --run-mode=badass --traffic-ops-url=https://trafficops.infra.ciab.test --traffic-ops-user=admin --traffic-ops-password=twelve12 --git=yes --dispersion=0 --log-location-error=stdout --log-location-warning=stdout --log-location-info=stdout all
API server listening at: [::]:2349

The API server listening message is from dlv, indicating it is ready to accept a connection from your IDE. Note that, unlike the other components, execution of t3c does not begin until your IDE connects to dlv.

For this example, set a breakpoint at the assignment of “##OVERRIDDEN## “ + str to newstr in torequest.processRemapOverrides().

Use the debugging configuration you created to connect to dlv and start debugging t3c.

Traffic Monitor

Navigate to the infrastructure/cdn-in-a-box directory. Remove the existing RPMs because they contain release Go binaries do not include useful debugging information. Rebuild the RPMs with no optimization, for debugging:
#109 Remove release RPMs, then build debug RPMs
make very-clean make debug traffic_monitor/traffic_monitor.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native traffic_monitor/traffic_monitor.rpm instead of make debug traffic_monitor/traffic_monitor.rpm to build the RPM quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set TM_DEBUG_ENABLE to true.
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the trafficmonitor-debug image to make sure it uses our fresh traffic_monitor.rpm. Then, start CDN-in-a-Box:
#110 docker compose command for debugging Traffic Monitor
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build trafficmonitor mydc up

Install an IDE that supports delve and create a debugging configuration over port 2344. If you are using VS Code, the configuration should look like this:

#111 VS Code launch.json for debugging Traffic Monitor

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Traffic Monitor",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2344,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Use the debugging configuration you created to start debugging Traffic Monitor. It should connect without first breaking at any line.

For an example of usage, set a breakpoint at the o.m.RLock() call in ThreadsafeEvents.Get(), then visit http://trafficmonitor.infra.ciab.test/publish/EventLog (see Traffic Monitor APIs: /publish/EventLog).

Traffic Ops

Navigate to the infrastructure/cdn-in-a-box directory. Remove the existing RPMs because they contain release Go binaries do not include useful debugging information. Rebuild the RPMs with no optimization, for debugging:
#112 Remove release RPMs, then build debug RPMs
make very-clean make debug traffic_ops/traffic_ops.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native traffic_ops/traffic_ops.rpm instead of make debug traffic_ops/traffic_ops.rpm to build the RPM quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set TO_DEBUG_ENABLE to true.
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the trafficops-debug image to make sure it uses our fresh traffic_ops.rpm. Then, start CDN-in-a-Box:
#113 docker compose command for debugging Traffic Ops
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build trafficops mydc up

Install an IDE that supports delve and create a debugging configuration over port 2345. If you are using VS Code, the configuration should look like this:

#114 VS Code launch.json for debugging Traffic Ops

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Traffic Ops",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2345,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Use the debugging configuration you created to start debugging Traffic Ops. It should connect without first breaking at any line.

For an example of usage, set a breakpoint at the log.Debugln() call in TOProfile.Read(), then visit https://trafficportal.infra.ciab.test/api/4.0/profiles (after logging into Traffic Portal).

Traffic Router

Navigate to the infrastructure/cdn-in-a-box directory.
In variables.env, set TR_DEBUG_ENABLE to true.
Install a debugging-capabe Java IDE or text editor of your choice. If unsure, install IntelliJ IDEA Community Edition.
At the base of the repository (not in the cdn-in-a-box directory), open the traffic_router directory in your IDE.
Add a new “Remote” (Java) debug configuration. Use port 5005.

Start CDN-in-a-Box, including the “expose ports” “debugging” compose files:

#115 docker compose command for debugging Traffic Router

alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml'
mydc down -v
mydc build trafficrouter
mydc up -d
mydc logs --follow trafficrouter

Watch the trafficrouter container’s log. After DNS and certificate operations, the enroller, and Traffic Monitor, Traffic Router will start. Look for Listening for transport dt_socket at address: 5005 in the example log below:

#116 Log of the Docker container for Traffic Router

        Warning:
        The JKS keystore uses a proprietary format. It is recommended to migrate to PKCS12 which is an industry standard format using "keytool -importkeystore -srckeystore /opt/traffic_router/conf/keyStore.jks -destkeystore /opt/traffic_router/conf/keyStore.jks -deststoretype pkcs12".
        Certificate stored in file <trafficrouter.infra.ciab.test.crt>

        Warning:
        The JKS keystore uses a proprietary format. It is recommended to migrate to PKCS12 which is an industry standard format using "keytool -importkeystore -srckeystore /opt/traffic_router/conf/keyStore.jks -destkeystore /opt/traffic_router/conf/keyStore.jks -deststoretype pkcs12".
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for enroller initial data load to complete....
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        Waiting for Traffic Monitor to start...
        tail: cannot open '/var/log/tomcat/catalina.log' for reading: No such file or directory
        tail: cannot open '/var/log/tomcat/catalina.2020-02-21.log' for reading: No such file or directory
        ==> /var/log/traffic_router/traffic_router.log <==

        ==> /var/log/traffic_routr/access.log <==
        Tomcat started.
        tail: '/var/log/tomcat/catalina.log' has appeared;  following end of new file
        tail: '/var/log/tomcat/catalina.2020-02-21.log' has appeared;  following end of new file

        ==> /var/log/traffic_router/traffic_router.log <==
        INFO  2020-02-21T05:16:07.557 [Thread-3] org.apache.traffic_control.traffic_router.protocol.LanguidPoller - Waiting for state from mbean path traffic-router:name=languidState
        INFO  2020-02-21T05:16:07.557 [Thread-4] org.apache.traffic_control.traffic_router.protocol.LanguidPoller - Waiting for state from mbean path traffic-router:name=languidState
        INFO  2020-02-21T05:16:07.558 [Thread-5] org.apache.traffic_control.traffic_router.protocol.LanguidPoller - Waiting for state from mbean path traffic-router:name=languidState
        INFO  2020-02-21T05:16:07.559 [Thread-6] org.apache.traffic_control.traffic_router.protocol.LanguidPoller - Waiting for state from mbean path traffic-router:name=languidState

        ==> /var/log/tomcat/catalina.log <==
        Listening for transport dt_socket at address: 5005

Watch for the line that mentions port 5005 -----------^^^^

        ==> /var/log/tomcat/catalina.2020-02-21.log <==
        21-Feb-2020 05:16:07.359 WARNING [main] org.apache.traffic_control.traffic_router.protocol.LanguidNioProtocol.<clinit> Adding BouncyCastle provider
        21-Feb-2020 05:16:07.452 WARNING [main] org.apache.traffic_control.traffic_router.protocol.LanguidNioProtocol.<init> Serving wildcard certs for multiple domains
        21-Feb-2020 05:16:07.459 WARNING [main] org.apache.traffic_control.traffic_router.protocol.LanguidNioProtocol.<init> Serving wildcard certs for multiple domains
        21-Feb-2020 05:16:07.459 WARNING [main] org.apache.traffic_control.traffic_router.protocol.LanguidNioProtocol.<init> Serving wildcard certs for multiple domains
        21-Feb-2020 05:16:07.461 INFO [main] org.apache.traffic_control.traffic_router.protocol.LanguidNioProtocol.setSslImplementationName setSslImplementation: org.apache.traffic_control.traffic_router.protocol.RouterSslImplementation

When you see that Tomcat is listening for debugger connections on port 5005, start debugging using the debug configuration that you created.

Traffic Stats

Navigate to the infrastructure/cdn-in-a-box directory. Remove the existing RPMs because they contain release Go binaries do not include useful debugging information. Rebuild the RPMs with no optimization, for debugging:
#117 Remove release RPMs, then build debug RPMs
make very-clean make debug traffic_stats/traffic_stats.rpm
Tip

If you have gone through the steps to Build the RPMs Natively, you can run make debug native traffic_stats/traffic_stats.rpm instead of make debug traffic_stats/traffic_stats.rpm to build the RPMs quickly.
Still in infrastructure/cdn-in-a-box, open variables.env and set TS_DEBUG_ENABLE to true.
Stop CDN-in-a-Box if it is running and remove any existing volumes. Build the trafficstats-debug image to make sure it uses our fresh traffic_stats.rpm. Then, start CDN-in-a-Box:
#118 docker compose command for debugging Traffic Stats
alias mydc='docker compose -f docker-compose.yml -f docker-compose.expose-ports.yml -f optional/docker-compose.debugging.yml' mydc down -v mydc build trafficstats mydc up

Install an IDE that supports delve and create a debugging configuration over port 2346. If you are using VS Code, the configuration should look like this:

#119 VS Code launch.json for debugging Traffic Stats

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Traffic Stats",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "port": 2346,
            "cwd": "${workspaceRoot}",
            "remotePath": "/tmp/go/src/github.com/apache/trafficcontrol",
        }
    ]
}

Use the debugging configuration you created to start debugging Traffic Stats. It should connect without first breaking at any line.

For an example of usage, set a breakpoint at the http.Get() call in main.getURL(), then wait 10 seconds for the breakpoint to be hit.

Troubleshooting

If you are debugging a Golang project and you don’t see the values of all variables, or stepping to the next line puts you several lines ahead, rebuild the Docker image with an RPM built using make debug.