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Prerequisites
It is assumed the VSCode Plugin and uip-cli version 2following are installed and configured properly:
- Opentelemetry Collector
- Jaeger
- Prometheus
- Grafana
- Universal Agent 7.5.0.0
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The development environment will be WSL (Windows Subsystem for Linux), however, it could be any of the supported platforms. The tutorial assumes a folder called demo_template has been opened in VSCode.
Introduction
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- or higher
- Universal Controller 7.5.0.0 or higher
- UIP-CLI
It is highly recommended to first go through The Basics, if this is the first time you are creating an Extension.
Introduction
To showcase the Opentelemetry functionality, we will be working with a basic File Monitor Extension that can monitor for creation and deletion of files.
Step 1 - Create the
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Extension
To create a custom starter template, we will first make use of the built-in ue-task template. Open up the terminal to the demo_template folder and run
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uip init -t ue-task -e "extension_name=my_custom_ext" -e "universal_template_name=my_custom_template" |
The directory structure should be as follows (not showing the Python *.pyc/__pycache__ files):
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demo_template/
├── .uip
│ └── config
│ └── uip.yml
├── __init__.py
├── requirements.txt
├── setup.cfg
├── setup.py
└── src
├── __init__.py
├── extension.py
├── extension.yml
└── templates
└── template.json |
The basic structure of the custom template is almost finished! Go ahead and create a file called template_config.yml at the same level as the src/ folder. The resulting directory tree is as follows:
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demo_template/
├── .uip
│ └── config
│ └── uip.yml
├── __init__.py
├── requirements.txt
├── setup.cfg
├── setup.py
├── src
│ ├── __init__.py
│ ├── extension.py
│ ├── extension.yml
│ └── templates
│ └── template.json
└── template_config.yml |
Step 2 - Configuring the Initial Template
To make the template configurable, add the following content below to template_config.yml:
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name: example-template
version: 1.0.0
description: this is the description for example template
files_to_template:
- src/extension.py
- src/templates/template.json
variables:
msg:
default: test_message
description: message to print to STDOUT and STDERR
log_level:
default: Info
description: Universal Template Log Level |
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Each
Although not required, it can also contain:
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Now, open src/extension.py and replace extension_start() with the code below:
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def extension_start(self, fields):
"""Required method that serves as the starting point for work performed
for a task instance.
Parameters
----------
fields : dict
populated with field values from the associated task instance
launched in the Controller
Returns
-------
ExtensionResult
once the work is done, an instance of ExtensionResult must be
returned. See the documentation for a full list of parameters that
can be passed to the ExtensionResult class constructor
"""
my_msg = "{{ msg }}"
# Get the value of the 'action' field
action_field = fields.get('action', [])
if len(action_field) != 1:
# 'action' field was not specified or is invalid
action = ''
else:
action = action_field[0]
if action.lower() == 'print':
# Print to standard output...
print(my_msg)
else:
# Log to standard error...
logger.info(my_msg)
# Return the result with a payload containing a Hello message...
return ExtensionResult(
unv_output='Hello Extension!'
) |
On line 19, a variable called my_msg is defined with the value of "{{ msg }}". This is Jinja2 syntax that will eventually be replaced with the specified value for msg (or the default, if they don’t specify anything) during initialization time.
On lines 31 and 34, the message was changed to print the value of my_msg.
Now, open src/templates/template.json and replace the value of logLevel key (should be around line 86) with the change shown below:
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"sysId": "535c354ed083489cb10413019d71a57c",
"textType": "Plain"
}
],
"logLevel": "{{ log_level | title }}",
"minReleaseLevel": "7.0.0.0",
"name": "my_custom_template", |
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Step 3 - Packaging the Initial Template
Although the example is a bit contrived, we have managed to create a fully-functional customized template.
To package the template, simply zip up everything into a file called example_template.zip (or whatever you want to call it). Its structure should be as follows (if *.pyc and __pycache__ files are there, it’s fine):
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