Debug CF

06 How do I debug my app?

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Feature

As a CF hero
I want to know what my CF app is doing
So that I can debug it

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Push a buggy app

# From the training home directory:
$ cd 06-debugging/debug-app
$ cf push

...

urls: debug-app-unerring-muddlehead.cfapps.io

...

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How do I debug my app?

1. App logs
2. App events
3. App instrumentation
4. SSH access

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1. App logs

$ cf logs debug-app --recent

...

... [App/0] ERR ...  - RuntimeError - I am a bug, fix me:
... [App/0] ERR /home/vcap/app/config.ru:20:in `block in <class:Web>

$ cf logs debug-app # Tails app logs, CTRL + C to exit

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Let's fix the app

$ cf set-env debug-app FIXED true
$ cf restart debug-app

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2. App events

$ cf events debug-app

... description
... index: 0, reason: CRASHED, exit_description: 2 error(s) ...
...

Note: Notice that the most recent event is at the top

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3. App instrumentation

• New Relic
• AppDynamics

Included in Java buildpack

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New Relic instrumentation

$ cf create-service newrelic standard newrelic
$ cf bind-service debug-app newrelic
$ cf env debug-app
# Find your New Relic license key

# From the training home directory:
$ cd 06-debugging/debug-app
# Replace YOUR-LICENSE-KEY
$ vim newrelic.yml

$ cf push

$ cf service newrelic

Note: Create a New Relic service instance

Provide app with New Relic license key

Find New Relic Dashboard URL

Generate some load

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4. SSH access

$ cf ssh debug-app

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DELIVERED

As a CF hero
I want to know what my CF app is doing
So that I can debug it

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Any questions?

Questions cannot be stupid. Answers can.

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CF SUPERHERO

• Setup Skylight for app
• Setup Opbeat for app
• Learn about CF Logging and Metrics
• Send app logs to Papertrail

$ cf cups logdrain -l syslog://YOUR-PAPERTRAIL-LOG-DESTINATION
$ cf bind-service debug-app logdrain
# Check your Papertrail Events, no need to restart the app