Acces to config out of Flask context (#55)

* Create Microservice class with singleton to import config in any file

* Updated doc and examples

* Updated dependencies

* Updated tests dependencies

* increment version

Author: avara1986

.gitignore

@@ -22,4 +22,7 @@ pylintReport.txt
 
 # Deploy
 build/
-dist/
+dist/
+
+# other
+site/*

Pipfile

@@ -4,14 +4,15 @@ verify_ssl = true
 name = "pypi"
 
 [packages]
-flask = "*"
+flask = ">=1.1.1"
 python-json-logger = ">=0.1.10"
-pyyaml = ">=4.2b4"
+pyyaml = ">=5.1.2"
 anyconfig = ">=0.9.8"
 swagger-ui-bundle = ">=0.0.2"
 connexion = {extras = ["swagger-ui"],version = ">=2.2.0"}
-lightstep = "*"
+lightstep = "==4.1.0"
 flask-opentracing = "*"
+opentracing = ">=2.0.0"
 
 [dev-packages]
 requests-mock = "*"

Pipfile.lock

@@ -1,7 +1,11 @@
 # Configuration
 
+## Create configuration
 Each microservice needs a config file in yaml or json format to work with it. This configuration contains
-the Flask settings of your project and the [Services](services.md).
+the Flask settings of your project and the [Services](services.md). With this way to create configuration files, we 
+solve two problems of the [12 Factor apps](https://12factor.net/):
+- Store config out of the code
+- Dev/prod parity: the configuration could be injected and not depends of our code, for example, Kubernetes config maps
 
 a simple configuration file could be a config.yaml:
 
@@ -91,3 +95,51 @@ ms1-api:
   DEBUG: true
   TESTING: false
 ```
+
+## Import Configuration
+With pyms, all configuration is stored as flask configuration and it can be acceded from:
+
+```python
+from flask import current_app; 
+
+def my_endpoint():
+	print(current_app.config["DEBUG"])
+```
+
+But, what happend if you need the configuration BEFORE Flask class is instanced? Imagine this case:
+
+```python
+from flask import Blueprint, current_app
+from flask_restplus import Api
+
+my_api_blueprint = Blueprint('api', __name__)
+
+API = Api(
+    my_api_blueprint,
+    title='My Microservice',
+    version=current_app.config["APP_VERSION"],
+    description='Microservice to manage hierarchies',
+    add_specs=True,
+)
+```
+
+This raise a `'working outside of application context` error. Who can solve this problem?
+
+```python
+from flask import Blueprint, current_app
+from flask_restplus import Api
+from pyms.flask.app import config
+
+my_api_blueprint = Blueprint('api', __name__)
+
+API = Api(
+    my_api_blueprint,
+    title='My Microservice',
+    version=config().APP_VERSION,
+    description='Microservice to manage hierarchies',
+    add_specs=True,
+)
+```
+
+**IMPORTANT:** If you use this method to get configuration out of context, you must set the `CONFIGMAP_SERVICE` or set 
+the default key `ms` for your configuration block in your config.yml

docs/configuration.md

@@ -0,0 +1,3 @@
+from pyms.flask.app import Microservice
+
+ms = Microservice(path=__file__)

examples/__init__.py

@@ -0,0 +1,15 @@
+pyms:
+  requests:
+    data: ""
+  swagger:
+    path: ""
+    file: "swagger.yaml"
+my-configure-microservice:
+  DEBUG: true
+  TESTING: false
+  APP_NAME: "Python Microservice"
+  APPLICATION_ROOT: ""
+  request_variable_test: "this is a test"
+  MyVar: "this is MyVar"
+  test1: "ttest1"
+  test2: "ttest2"

examples/microservice_configuration/__init__.py

@@ -0,0 +1,9 @@
+from examples.microservice_configuration import ms
+app = ms.create_app()
+
+if __name__ == '__main__':
+    """
+    run first:
+    export CONFIGMAP_SERVICE=my-configure-microservice
+    """
+    app.run()

examples/microservice_configuration/config.yml

@@ -0,0 +1,55 @@
+---
+swagger: "2.0"
+info:
+  description: "This is a sample server Test server"
+  version: "1.0.0"
+  title: "Swagger Test list"
+  termsOfService: "http://swagger.io/terms/"
+  contact:
+    email: "apiteam@swagger.io"
+  license:
+    name: "Apache 2.0"
+    url: "http://www.apache.org/licenses/LICENSE-2.0.html"
+tags:
+- name: "colors"
+  description: "Everything about your colors"
+  externalDocs:
+    description: "Find out more"
+    url: "http://swagger.io"
+- name: "store"
+  description: "Example endpoint  list of colors"
+- name: "user"
+  description: "Operations about user"
+  externalDocs:
+    description: "Find out more about our store"
+    url: "http://swagger.io"
+schemes:
+- "http"
+paths:
+  /:
+    get:
+      tags:
+      - "test"
+      summary: "Example endpoint"
+      description: ""
+      operationId: "examples.microservice_configuration.views.example"
+      consumes:
+      - "application/json"
+      produces:
+      - "application/json"
+      responses:
+        200:
+          description: "A list of colors (may be filtered by palette)"
+          schema:
+            $ref: '#/definitions/Example'
+        405:
+          description: "Invalid input"
+definitions:
+  Example:
+    type: "object"
+    properties:
+      main:
+        type: "string"
+externalDocs:
+  description: "Find out more about Swagger"
+  url: "http://swagger.io"

examples/microservice_configuration/main.py

@@ -0,0 +1,13 @@
+from pyms.flask.app import config
+
+GLOBAL_VARIABLE = config().request_variable_test
+GLOBAL_VARIABLE2 = config().MyVar
+
+
+def example():
+    return {
+        "GLOBAL_VARIABLE": GLOBAL_VARIABLE,
+        "GLOBAL_VARIABLE2": GLOBAL_VARIABLE2,
+        "test1": config().test1,
+        "test2": config().test2
+    }