Add support for Emit and Loggers and more...

.github/workflows/checks.yaml

@@ -0,0 +1,17 @@
+name: checks
+on:
+  pull_request:
+    paths-ignore:
+      - ".github/**"
+
+jobs:
+  check-changelog:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Check Changelog modified
+        uses: dangoslen/changelog-enforcer@v3
+        with:
+          changeLogPath: "./CHANGELOG.md"
+          missingUpdateErrorMessage: |
+            Please include an entry into `CHANGELOG.md` to describe what happened in the PR

.github/workflows/components-test.yaml

@@ -0,0 +1,24 @@
+name: distro component test
+
+on:
+  pull_request:
+    branches: [ main ]
+
+env:
+  GO_VERSION: 1.22.x
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Go ${{ env.GO_VERSION }}
+        uses: actions/setup-go@v4
+        with:
+          go-version: ${{ env.GO_VERSION }}
+
+      - name: test components
+        run: find . -name go.mod -execdir go test -v ./... \;
+

CHANGELOG.md

@@ -0,0 +1,11 @@
+## Otelity
+
+### v0.1.0 / 2024-12-15 (Breaking)
+- [Feat] add `emit` funciton to starlark processor
+- [Feat] added `log` module to starlark processor
+- [Feat] added `entrypoint` option to starlark config, allowing to specify the entry point of the starlark script/code
+- [Fix] `json.decode` no longer required to load telemetry events in starlark processor
+
+### v0.0.1 / 2024-12-07
+- [Feat] initial release
+    - starlark processor

processors/starlarkprocessor/README.md

@@ -1,17 +1,13 @@
-# starlarktransform
+# starlark
 
 <!-- status autogenerated section -->
-| Status        |           |
-| ------------- |-----------|
-| Stability     | [alpha]: traces, metrics, logs   |
 
-
-[beta]: https://github.com/open-telemetry/opentelemetry-collector#beta
-[sumo]: https://github.com/SumoLogic/sumologic-otel-collector
+| Status    |                                |
+|-----------|--------------------------------|
+| Stability | [alpha]: traces, metrics, logs |
 <!-- end autogenerated section -->
 
-
-The starlarktransform processor modifies telemetry based on configuration using Starlark code.
+The starlark processor modifies telemetry based on configuration using Starlark code.
 
 Starlark is a scripting language used for configuration that is designed to be similar to Python. It is designed to be fast, deterministic, and easily embedded into other software projects.
 
@@ -21,71 +17,70 @@ The processor leverages Starlark to modify telemetry data while using familiar,
 
 While there are a number of transform processors, most notably, the main OTTL [transform processor](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/transformprocessor), this processor aims to grant users more flexibility by allowing them to manipulate telemetry data using a familiar syntax.
 
-Python is a popular, well known language, even among non-developers. By allowing Starlark code to be used as an option to transform telemetry data, users can leverage their existing knowledge of Python.
-
+Python is a popular, well known language, even among non-developers. By allowing Starlark code to be used as an option to transform telemetry data, users can leverage their existing knowledge of Python to transform or manipulate their telemetry data.
 
 ## Config
 
-| Parameter | Desc |
-| ------- | ---- |
-| code | Add in-line starlark code directly to your config |
-| script | Allows you to set the script source. Supports __File path__ or __HTTP URL__ |
-
-To configure starlarktransform, you can add your code using the `code` option in the config.
+| Parameter  | Desc                                                                        |
+|------------|-----------------------------------------------------------------------------|
+| entrypoint | The name of the function to call when executing the starlark script         |
+| code       | Add in-line starlark code directly to your config                           |
+| script     | Allows you to set the script source. Supports **File path** or **HTTP URL** |
 
+To configure starlark, you can add your code using the `code` option in the config and specify the name of the function to call using the `entrypoint` option.
 
 ```yaml
 processors:
-  starlarktransform:
+  starlark:
+	entrypoint: transform
     code: |
       def transform(event):
         event = json.decode(event)
         <your starlark code>
         return event
 ```
 
-
 Alternatively, in cases where you prefer to not have starlark code present or visible in your Open Telemetry configuration, you can use the `script` parameter to pass your script from a file or http url.
 
 ```yaml
 processors:
-  starlarktransform:
+  starlark:
+	entrypoint: transform
 	script: /path/to/script.star
 
 # or
 processors:
-  starlarktransform:
+  starlark:
+	entrypoint: transform
 	script: https://some.url.com/script.star
 
 ```
 
-
-
-You must define a function called `transform` that accepts a single argument, `event`. This function is called by the processor and is passed the telemetry event. The function **must return** the modified, json decoded event.
-
+Your `entrypoint` must define a function that accepts a single argument, the name of the argument **does not** have to be `event` like the examples above. This function is called by the processor and is passed the telemetry event. The function **must return** the modified telemetry event.
 
 ## How it works
 
 The processor uses the [Starlark-Go](https://github.com/google/starlark-go) interpreter, this allows you to run this processor without having to install a Starlark language interpreter on the host.
 
 ## Features
 
-The starlarktransform processor gives you access to the full telemetry event payload. You are able to modify this payload using the Starklark code in any way you want. This allows you do various things such as:
+The starlark processor gives you access to the full telemetry event payload. You are able to modify this payload using the Starklark code in any way you want. This allows you do various things such as:
 
 - Filtering
 - Adding/Removing attributes
 - Modifying attributes
 - Modifying telemetry data directly
 - Telemetry injection based on existing values
-- And more
+- Live, detailed, telemetry data debugging and evaluation
+- And much more
 
-## Libs, Functions and Functionality
+## Modules, Functions and Functionality
 
 While similar in syntax to Python, Starlack does not have all the functionality associated with Python. This processor does not have access to Python standard libraries and the implementation found in this processor is limited further to only the following libraries and functions:
 
 - **json**
 
-> The JSON library allows you to encode and decode JSON strings. The use of this library is mandatory as the telemetry data is passed to the processor as a JSON string. You must decode the JSON string to a Dict before you can modify it. **You must also return a JSON decoded Dict to the processor.**
+The JSON library allows you to encode and decode JSON strings. The use of this library is mandatory as the telemetry data is passed to the processor as a JSON string. You must decode the JSON string to a Dict before you can modify it. **You must also return a JSON decoded Dict to the processor.**
 
 ```python
 # encode dict string to json string
@@ -101,31 +96,43 @@ x = json.decode('{"foo": ["bar", "baz"]}')
 
 You can read more on the JSON library [here](https://qri.io/docs/reference/starlark-packages/encoding/json)
 
-- **print**
-> You are able to use the print function to check outputs of your code. The output of the print function is sent to the Open Telemetry runtime log. Values printed by the Print function only show when running Open Telemetry in Debug mode.
+- **log** modules and **print** function
+
+You are able to use the print function or log module to print output to the Open Telemetry runtime log. This is useful for debugging your Starlark code as well as general logging based on evaluation of the telemetry data. For example, you may want to print a log message if certain values or behaviors are identified in the telemetry data.
 
 ```python
 def transform(event):
 	print("hello world")
 	return json.decode(event)
 ```
 
-The print statement above would result in the following output in the Open Telemetry runtime log. Again, this output is only visible when running Open Telemetry in Debug mode.
+The print statement above would result in the following output in the Open Telemetry runtime log when opentelemetry is run in debug mode:
+
 ```log
-2023-09-23T16:50:17.328+0200	debug	traces/processor.go:25	hello world	{"kind": "processor", "name": "starlarktransform/traces", "pipeline": "traces", "thread": "trace.processor", "source": "starlark/code"}
+2023-09-23T16:50:17.328+0200	debug	traces/processor.go:25	hello world	{"kind": "processor", "name": "starlark/traces", "pipeline": "traces", "thread": "trace.processor", "source": "starlark/code"}
 ```
 
+If you want to log messages outside of the debug mode, you can use the log module:
 
-- **re** (regex)
-> Support for Regular Expressions coming soon
+```python
+def transform(event):
+	log.info("hello world")
+	return json.decode(event)
+```
+
+There are 3 log levels available: - `log.info` - `log.warn` - `log.error`
 
+Again, note that the debug level is handled by the `print` function and is only available in debug mode.
 
-Note that you can define your own functions within your Starlark code, however, there must be at least one function named `transform` that accepts a single argument `event` and returns a JSON decoded Dict, this function can call all your other functions as needed.
+- **re** (regex)
 
+> Support for Regular Expressions coming soon
+
+Note that you can define your own functions within your Starlark code, and call them as required, however, there must be at least one entrypoint function that accepts a single argument telemetry event argument and returns the modified event.
 
 ## Examples
 
-This section contains examples of the event payloads that are sent to the starlarktransform processor from each telemetry type. These examples can help you understand the structure of the telemetry events and how to modify them.
+This section contains examples of the event payloads that are sent to the starlark processor from each telemetry type. These examples can help you understand the structure of the telemetry events and how to modify them.
 
 ##### Log Event Payload Example:
 
@@ -211,6 +218,7 @@ View the the log.proto type definition [here](https://github.com/open-telemetry/
 	}]
 } 
 ```
+
 View the metric.proto type definition [here](https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/metrics/v1/metrics.proto)
 
 ##### Trace Event Payload Example:
@@ -346,10 +354,9 @@ View the metric.proto type definition [here](https://github.com/open-telemetry/o
 
 View the trace.proto type definition [here](https://github.com/open-telemetry/opentelemetry-proto/blob/main/opentelemetry/proto/trace/v1/trace.proto).
 
-
 ## Full Configuration Example
 
-For following configuration example demonstrates the starlarktransform processor telemetry events for logs, metrics and traces.
+For following configuration example demonstrates the starlark processor telemetry events for logs, metrics and traces.
 
 ```yaml
 receivers:
@@ -381,10 +388,9 @@ processors:
   # - add resource attribute cluster: dev
   # - filter out any logs that contain the word password
   # - add an attribute to each log: language: golang
-  starlarktransform/logs:
+  starlark/logs:
     code: |
       def transform(event):
-        event = json.decode(event)
         # edit resource attributes
         for data in event['resourceLogs']:
           for attr in data['resource']['attributes']:
@@ -405,13 +411,12 @@ processors:
 
         return event
   # - print event received to otel runtime log
-  # - if there are no resources, add a resource attribute source starlarktransform
-  # - prefix each metric name with starlarktransform
-  starlarktransform/metrics:
+  # - if there are no resources, add a resource attribute source starlark
+  # - prefix each metric name with starlark
+  starlark/metrics:
     code: |
       def transform(event):
         print("received event", event)
-        event = json.decode(event)
         for md in event['resourceMetrics']:
           # if resources are empty
           if not md['resource']:
@@ -420,31 +425,30 @@ processors:
                 {
                   "key": "source",
                   "value": {
-                    "stringValue": "starlarktransform"
+                    "stringValue": "starlark"
                   }
                 }
               ]
             }
 
-          # prefix each metric name with starlarktransform
+          # prefix each metric name with starlark
           for sm in md['scopeMetrics']:
             for m in sm['metrics']:
-              m['name'] = 'starlarktransform.' + m['name']
+              m['name'] = 'starlark.' + m['name']
 
         return event
 
-  # - add resource attribute source starlarktransform
+  # - add resource attribute source starlark
   # - filter out any spans with http.target /roll attribute
-  starlarktransform/traces:
+  starlark/traces:
     code: |
       def transform(event):
-        event = json.decode(event)
         for td in event['resourceSpans']:
           # add resource attribute
           td['resource']['attributes'].append({
             'key': 'source',
             'value': {
-              'stringValue': 'starlarktransform'
+              'stringValue': 'starlark'
             }
           })
 
@@ -467,29 +471,37 @@ service:
       receivers:
       - filelog
       processors:
-      - starlarktransform/logs
+      - starlark/logs
       exporters:
       - logging
 
     metrics:
       receivers:
       - otlp
       processors:
-      - starlarktransform/metrics
+      - starlark/metrics
       exporters:
       - logging
 
     traces:
       receivers:
       - otlp
       processors:
-      - starlarktransform/traces
+      - starlark/traces
       exporters:
       - logging
 ```
 
+### Performance
 
-### Warnings
+The graph below shows a comparison of the starklark processor vs the transform processor. While the starlark processor is far from slow, the transform processor is twice as fast overall when performing the same type of transformation. If speed is a concern, you may want to consider using the transform processor instead.
 
-The starlarktransform processor allows you to modify all aspects of your telemetry data. This can result in invalid or bad data being propogated if you are not careful. It is your responsibility to inspect the data and ensure it is valid.
+<p align="center">
+  <img src="../../misc/starlark-vs-transform.jpg">
+</p>
+
+The starklark processor is a great component for highly complex or specialised types of transformations that simply can't be performed using the transform processor.
+
+### Warnings
 
+The starlark processor allows you to modify all aspects of your telemetry data. This can result in invalid or bad data being propogated if you are not careful. It is your responsibility to inspect the data and ensure it is valid.

processors/starlarkprocessor/config.go

@@ -17,13 +17,20 @@ type Config struct {
 	// source of startlark script
 	// accepts both file path and url
 	Script string `mapstructure:"script"`
+
+	// entrypoint -  the name of the funciton to be called
+	EntryPoint string `mapstructure:"entrypoint"`
 }
 
 func (c *Config) validate() error {
 	if c.Code == "" && c.Script == "" {
 		return errors.New("a value must be given for altest one, [code] or [script]")
 	}
 
+	if c.EntryPoint == "" {
+		return errors.New("[entrypoint] must be provided")
+	}
+
 	return nil
 }