[APM] Update agent configuration snippets to include service environment variable

[formgeist]

Summary

We want to include the service environment configuration in the default agent configuration snippets to make it clear that we're setting a default unless otherwise specified in an effort to do away with services with empty environment values. Environments are becoming a critical part of the product - we use it for anomaly detection and agent configuration, and we're seeing more and more issues with the environments added are not aligned or used, so data is mixed up when analyzing it using the APM app.

Solution

Update the getting started tutorial snippets for each agent to exemplify the environment variable and note that the agent is using a default value already, in case the user wishes to change it before data starts coming in.

Here's an example from the Python (Django) snippets revised;

Source:

kibana/src/plugins/apm_oss/server/tutorial/instructions/apm_agent_instructions.ts

Line 18 in 827ee5c

*/

# Add the agent to the installed apps
INSTALLED_APPS = (
  'elasticapm.contrib.django',
  # ...
)

ELASTIC_APM = {
  # Set required service name. Allowed characters:
  # a-z, A-Z, 0-9, -, _, and space
  'SERVICE_NAME': '',

  # Use if APM Server requires a token
  'SECRET_TOKEN': '',

  # Set custom APM Server URL (default: http://localhost:8200)
  'SERVER_URL': '',

  # Set service environment variable (default: production)
  'ENVIRONMENT': '',
}

# To send performance metrics, add our tracing middleware:
MIDDLEWARE = (
  'elasticapm.contrib.django.middleware.TracingMiddleware',
  #...
)

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[bmorelli25]

I can make this change if you'd like!

[formgeist]

@bmorelli25 Did you want to pick this up? That'd be a great help and addition 👍

[bmorelli25]

Yup, planning on getting it in today. Just saw that @smith moved it to 7.12 though?

[smith]

@bmorelli25 please feel free to move it back if you're on it.