Add Sphinx documentation and GitHub Pages workflow

.github/workflows/documentation.yml

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+name: Publish documentation to GitHub Pages
+
+on:
+  release:
+    types: [ created ]
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
+      - name: Checkout code
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Set up Python 3.10
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: "3.10"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install uv
+          uv pip install --system -r docs/requirements_docs.txt
+
+      - name: Build documentation
+        run: cd docs && make html
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
+        with:
+          path: './docs/build/html'
+
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5

.gitignore

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+.idea/
+
+docs/build/

docs/Makefile

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+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = source
+BUILDDIR      = build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

docs/make.bat

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+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=source
+set BUILDDIR=build
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.https://www.sphinx-doc.org/
+	exit /b 1
+)
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd

docs/requirements_docs.txt

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+sphinx
+sphinx_rtd_theme
+sphinxcontrib-openapi

docs/source/_static/schema.yaml

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+swagger: "2.0"
+info:
+  title: OpenGRIS Adapter Webhook OpenAPI Schema
+  version: "1.0.0"
+paths:
+  /:
+    post:
+      summary: Webhook endpoint for OpenGRIS Adapter
+      parameters:
+        - in: body
+          name: body
+          required: true
+          schema:
+            type: object
+            properties:
+              action:
+                description: Action to perform. Valid values are 'start_worker_group' and 'shutdown_worker_group'.
+                type: string
+                enum:
+                  - start_worker_group
+                  - shutdown_worker_group
+              worker_group_id:
+                description: |
+                  Unique identifier for the worker group. **Note**: This ID might be ignored when performing 
+                  the 'start_worker_group` action, as the server may generate its own ID instead.
+                type: string
+              metadata:
+                description: |
+                  Optional metadata provided by the scheduler's scaling policy. May include details like instance type,
+                  region, image tags, etc.
+                type: object
+              auth_token:
+                description: |
+                  Optional authentication token for securing the webhook from unauthorized requests. Must match the 
+                  server's expected token if provided.
+                type: string
+            required:
+              - action
+      responses:
+        200:
+          description: Successful response
+          schema:
+            type: object
+            properties:
+              status:
+                description: Status of the requested action.
+                type: string
+              worker_group_id:
+                description: |
+                  Unique identifier for the worker group. **Note**: This ID may not match the one provided in
+                  the request if the server generates its own ID when starting a new worker.
+                type: string
+              worker_ids:
+                description: |
+                  List of unique identifiers for the worker instances within the group.
+                type: array
+                items:
+                  type: string
+              metadata:
+                description: |
+                  Optional metadata about the worker instance. May include details like instance type,
+                  region, image tags, etc.
+                type: object
+                properties: { }
+            required:
+              - status
+        400:
+          description: Bad Request, e.g., missing required fields or invalid action
+          schema:
+            $ref: '#/definitions/Error'
+        401:
+          description: Unauthorized, e.g., invalid or missing auth_token
+          schema:
+            $ref: '#/definitions/Error'
+        429:
+          description: Too Many Requests, e.g. rate limiting, no available resources
+          schema:
+            $ref: '#/definitions/Error'
+        500:
+          description: Internal Server Error, e.g., server-side or infrastructure related issues
+          schema:
+            $ref: '#/definitions/Error'
+definitions:
+  Error:
+    type: object
+    properties:
+      error:
+        type: string
+    required:
+      - error

docs/source/adapter/scaling.rst

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+Scaling Controller
+==================
+
+The scaling controller determines when to start and stop workers based on task and other state updates emitted by 
+the scheduler. The scaling controller implements a scaling policy that can suit specific needs such as:
+
+- Cost optimized: Start and stop workers based on task queue length and worker idle time.
+- Performance optimized: Start workers as soon as tasks are available.
+- Time constrained: Start workers based on a schedule.
+- Resource constrained: Start and stop workers based on available budget or resource quotas.
+
+To perform a scaling action, the scaling controller sends a webhook request to the adapter. The adapter then starts or
+stops workers as requested.
+
+Scaling Controller Interface
+----------------------------
+
+.. code-block:: python
+
+    import abc
+
+    from scaler.protocol.python.message import InformationSnapshot
+    from scaler.utility.mixins import Reporter
+
+    class ScalingController(Reporter, abc.ABC):
+        def get_status(self):
+            pass
+
+        async def on_snapshot(self, information_snapshot: InformationSnapshot):
+            pass
+
+Implementing a Scaling Controller
+---------------------------------
+
+Some pointers to implement a robust Scaling Controller:
+
+- Decide when to scale up:
+    - if backlog > threshold OR average task wait time > latency_target, issue a start_worker_group webhook
+    - include suggested instance type, region, and any labels in metadata
+- Decide when to scale down:
+    - if backlog is small or task wait time is low, issue a shutdown_worker_group webhook for specific worker_group_id
+- Validate webhook responses: only treat action as completed when adapter returns 200
+- Use exponential backoff for retries when receiving 429 or 5xx responses from the adapter
+- Idempotency: you may include a request identifier in metadata if your adapter supports it, or detect repeated requests
+  and avoid duplicate actions.
+- Observability: emit metrics for actions issued, successful starts/stops, failures, and retries

docs/source/adapter/webhook.rst

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+Adapter Webhook API
+===================
+
+The Adapter Webhook API provides a single unified endpoint for the scheduler to request the start and stop of workers.
+
+Webhook Specification
+---------------------
+
+.. openapi:: ../_static/schema.yaml
+
+Webhook Request Examples
+------------------------
+
+Example: start_worker_group (minimal)
+
+.. code-block:: json
+
+    {
+      "action": "start_worker_group"
+    }
+
+Example: start_worker_group (with suggested worker_group_id and auth)
+
+.. code-block:: json
+
+    {
+      "action": "start_worker_group",
+      "worker_group_id": "worker-group-12345",
+      "metadata": {
+        "instance_type": "m8gd.16xlarge",
+        "region": "us-east-1",
+        "image_tag": "python:3.11-alpine",
+        "tags": ["python"]
+      },
+      "auth_token": "<your-webhook-token>"
+    }
+
+Example: shutdown_worker
+
+.. code-block:: json
+
+    {
+      "action": "shutdown_worker_group",
+      "worker_group_id": "worker-group-12345"
+    }
+
+Webhook Reponse Examples
+------------------------
+
+Success (200)
+
+.. code-block:: json
+
+    {
+      "status": "ok",
+      "worker_group_id": "worker-group-12345",
+      "worker_ids": ["worker-1", "worker-2", "worker-3"],
+      "metadata": {
+        "instance_type": "m8gd.16xlarge",
+        "region": "us-east-1"
+      }
+    }
+
+Client error (400)
+
+.. code-block:: json
+
+    {
+      "error": "missing required field 'action'"
+    }
+
+Unauthorized (401)
+
+.. code-block:: json
+
+    {
+      "error": "invalid auth_token"
+    }
+
+Rate limit / resource unavailable (429)
+
+.. code-block:: json
+
+    {
+      "error": "no available capacity, retry later"
+    }
+
+Server error (500)
+
+.. code-block:: json
+
+    {
+      "error": "internal provisioning error"
+    }
+
+Scaling Controller Interaction
+------------------------------
+
+Interactions with the scaling controller can be complex given the possibility of dependency failures, network issues,
+delays, etc. Here are some guidelines to ensure reliable communication between the scaling controller and the adapter:
+
+- **Return the correct error code**: Return an appropriate HTTP status to indicate how the controller should proceed:
+    - 200: action completed successfully (include resulting worker_id)
+    - 400: client error — fix the request (do not retry)
+    - 401: unauthorized — reject immediately
+    - 429: retryable (rate limiting or temporary lack of capacity) — controller should back off and retry
+    - 5xx: server error — controller should retry with backoff
+- **Blocking vs asynchronous actions**: The adapter SHOULD complete the requested action before returning 200. If the
+  adapter cannot complete the action synchronously, return 202 Accepted and provide a status endpoint or include a
+  request_id in the response so the controller can poll for completion.
+- **Idempotency**: Support idempotent requests. If a controller retries the same start/stop request, the adapter should
+  detect duplicates (eg. via a request id in metadata) and avoid double-provisioning.
+- **Validation**: Validate incoming payloads and return 400 for malformed requests. Include a helpful error message in the
+  body following the Error schema.
+- **Security**: Require an auth_token or use mutual TLS. Reject invalid auth with 401.

docs/source/conf.py

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+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
+
+project = "OpenGRIS"
+copyright = "2025, Citi"
+author = "Citi"
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+extensions = ["sphinxcontrib.openapi"]
+
+templates_path = ["_templates"]
+exclude_patterns = []
+
+
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
+
+html_theme = "sphinx_rtd_theme"
+html_static_path = ["_static"]