Open Source Probe: April 2020

What is this WSO2 API Microgatway?

"The WSO2 API Microgateway is a lightweight message processor for APIs. The API Microgateway is used for message security, transport security, routing, and other common API Management related quality of services. It can process incoming and outgoing messages while collecting information required for usage metering and throttling capabilities. The API Microgateway natively supports scaling in highly decentralized environments including microservice architecture. An immutable, ephemeral Microgateway fits well with the microservice architecture. The API Microgateway is also capable of operating in lockdown environments such as IoT devices since connectivity from the API Microgateway to the API Management system is not mandatory."

In summary, WSO2 API Microgateway is a lightweight gateway distribution that can be used to deploy a single API or multiple APIs, i.e. WSO2 API Microgateway is a specialized form of WSO2 API Gateway.

In this use case let's see how a service can be securely proxied via WSO2 API Microgateway 3.1.0. Let's expose the publicly available petstore services (https://petstore.swagger.io/v2/ ) using the microgateway.

This use case is carried on the following environment.

OS: macOS Catalina V10.15.3
JAVA: Java(TM) SE Runtime Environment (build 1.8.0_162-b12)

Consider the following installation prerequisites.

Docker - Mine was docker desktop community: V2.2.0.3 (42716) stable channel

If you already don't have docker installed, please follow [1] and install.
Once you have completed installation run docker for desktop and in terminal, run docker info and check status.

WSO2 API Microgateway toolkit - Mine was V3.1.0 latest release at the time of writing this article.

Go to https://wso2.com/api-management/api-microgateway/ and download TOOLKIT -> MacOS Zip Archive
Extract it do a location of your choice and lets call it <MGWTK_HOME>
e.g. /Users/Shared/wso2/packs/wso2am-micro-gw-toolkit-macos-3.1.0
Append the full path including /bin to PATH environment variable as follows.

With Catalina upgrade now most of you are using ~/.zprofile [2] to maintain your PATH variables. Add following two lines to this file.
export MGWTK_HOME=/Users/Shared/wso2/packs/wso2am-micro-gw-toolkit-macos-3.1.0
export PATH=$MGWTK_HOME/bin:$PATH
Run source ~/.zprofile to refresh the changed zprofile file.

Run micro-gw version
JAVA_HOME: /Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home

3.1.0

Now let's begin.

Navigate to your workspace directory of your choice.
Using famous online petstore API definition lets initialize petstore project as follows.
micro-gw init petstore -a https://petstore.swagger.io/v2/swagger.json
JAVA_HOME: /Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home

Project 'petstore' is initialized successfully.

(Use "micro-gw build petstore" after copying the api definitions)

(Use "micro-gw import petstore [-l]|[-a -v]" to import APIs from WSO2 API Manager)
Using tree command [3] check the newly created directory structure as follows.
user % tree

.

└── petstore

├── api_definitions

│   └── swagger.json

├── conf

│   └── deployment-config.toml

├── extensions

│   ├── extension_filter.bal

│   ├── startup_extension.bal

│   └── token_revocation_extension.bal

├── grpc_definitions

├── interceptors

├── lib

└── policies.yaml
Now build the project and the docker image as follows.
micro-gw build petstore --docker --docker-image petstore:v1 --docker-base-image wso2/wso2micro-gw:3.1.0-alpha
You can see the following output.
JAVA_HOME: /Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home

Generating sources...[DONE]

..................................

There are no new updates available

..................................

Compiling source

wso2/petstore:3.1.0

Creating balos

target/balo/petstore-2019r3-java8-3.1.0.balo

Running tests

wso2/petstore:3.1.0

No tests found

Generating executables

target/bin/petstore.jar

Generating docker artifacts...

@docker - complete 2/2

Run the following command to start a Docker container:

docker run -d petstore:v1

BUILD SUCCESSFUL

Target: /Users/Shared/wso2/testbed/microgw-3.1.0/petstore/target/petstore.jar
Now let's expose this petstore API via WSO2 API Microgateway Docker image as follows.
docker run -d -p 9090:9090 -p 9095:9095 petstore:v1

105edc5b762c767a3c8ddf2637754698bd3fa26527d7c7f3c25dafc05ba7f25c

Run following command to check just to the newly created image for yourself.
docker images
REPOSITORY TAG IMAGE ID CREATED SIZE

petstore v1 34a5cb70edda About a minute ago 288MB

wso2/wso2micro-gw 3.1.0-alpha 8a050f202d8d 7 weeks ago 250MB

wso2/micro-integrator 1.1.0 088477c689f6 6 months ago 315MB
Invoking the API resource.

Consider API resource pet/{petId}. As you can see in https://petstore.swagger.io/v2/swagger.json, this resource is secured using an API Key in api_key header as follows.
paths:
'/pet/{petId}':
get:
security:
- api_key: []
securityDefinitions:
api_key:
type: apiKey
name: api_key
in: header

Therefore let's obtain a token which will be used to invoke this API.
TOKEN=$(curl -X get "https://localhost:9095/apikey"
-H "Authorization:Basic YWRtaW46YWRtaW4=" -k)

% Total % Received % Xferd Average Speed Time Time Time Current

Dload Upload Total Spent Left Speed

100 621 0 621 0 0 2171 0 --:--:-- --:--:-- --:--:-- 2171

You can checkout the token as follows.

echo $TOKEN

eyJhbGciOiJSUzI1NiIsICJ0eXAiOiJqd3QiLCAia2lkIjoiYmFsbGVyaW5hIn0.eyJzdWIiOiJhZG1pbiIsICJpc3MiOiJodHRwczovL2xvY2FsaG9zdDo5MDk1L2FwaWtleSIsICJpYXQiOjE1ODY0MTYxNzgsICJqdGkiOiIzMjUxYTQ3OC1kYWFiLTQ2OTQtYTIzYi04NWMyYmZiYThmYjciLCAia2V5dHlwZSI6IlBST0RVQ1RJT04iLCAiYWxsb3dlZEFQSXMiOltdfQ.PJCB_XuY6F_Ph-NoMNlZRcrnXdk9-Dfflc49MRETjnzL6Z7Wyg6w4iyeNwmGkHhqk2SUqoOmZ7ZucT7ZmLMCe_ejoPVXTmvX9QtnF8gab3zE1Ww4yA8sVzCNVJWXQiPzkoiJ4yPX-e6CxEzluYQJLbL9H8icP9xpkTcck7kLo-vNqsT3gylQPBn39ZQnaFwkJeX1gFRi6G3-MwgPQhU2vRT1NAWCZdrYjPX0JB1BG_KOYUgWAbkc66UJBGgj0-b8_8eYoJ2_AmWlYEWEmpb8iK-BY6pTjYcFAEOB6Q28K-QglVSBkdTa-tQCfYkN9enJwFhd4Mr6_3pHcxQrgZ71xA
Now using this newly obtained token stored in TOKEN variable let's invoke the API resource as follows. Note that I have piped json_pp at the end to pretty print json response [3].
curl -X GET "https://localhost:9095/v2/pet/1" -H "accept: application/json" -H "api_key:$TOKEN" -k | json_pp

  % Total % Received % Xferd Average Speed Time Time Time Current

   Dload Upload Total Spent Left Speed

100 201 0 201 0 0 152 0 --:--:-- 0:00:01 --:--:-- 152

{

   "status" : "available",

   "photoUrls" : [

"img/test/dog.jpeg",

"img/test/dog1.jpeg"

   ],

   "id" : 1,

   "category" : {

"name" : "Animal",

"id" : 1001

   },

   "tags" : [

{

   "name" : "Pet",

   "id" : 2001

},

{

   "name" : "Animal",

   "id" : 2002

}

   ],

   "name" : "doggie"

}