If you’re a blockchain based app developer, you may encounter situations that you need to listen events emitted from the smart contracts. Here, I will demonstrate a simple example on how to listen those events using Python. I’m using a simple smart contract Counter that emits an event carrying a…

This article provides step-by-step detailed guidelines to deploy a private blockchain using ethereum/client-go aka geth (go-ethereum) on docker. — If you’re reading this I assume that you already know blockchain 101 and basics of docker. Because in this article I’m more focussed on GETH commands and solving issues while deploying the ethereum/client-go docker image. …

If you are a user of GoodWe inverters and batteries, you might be interested in accessing the GoodWe Sems Portal API to retrieve data and integrate it into your own applications or systems. However, due to the lack of public documentation, it can be challenging to figure out how to…

In this article, I discuss how to attach an OPA policy to an API in WSO2 API Manager using a sample scenario — Open Policy Agent (OPA) is an open source and general-purpose policy engine that unifies policy enforcement across the stack. OPA is supported in WSO2 API Manager 4.1.0 onwards. Following steps will guide you on how to apply an OPA policy to an API. Run OPA as a server using Docker. …

Get this sample code and modify the CustomGatewayJWTGenerator.populateStandardClaims() method as below. @Override public Map<String, Object> populateStandardClaims(JWTInfoDto jwtInfoDto) { Map<String, Object> claims = super.populateStandardClaims(jwtInfoDto); claims.put("custom-attribute", "123"); return claims; } 2. Run mvn clean install and generate the jar file. 3. Copy CustomGatewayJWTGenerator-1.0-SNAPSHOT.jar to <APIM_HOME>/repository/components/dropins directory.

In this article, I discuss how to use WSO2 API Manager’s Publisher APIs to create and update Lambda APIs — WSO2 API Manager has built-in REST API support for managing all the tasks in the product and you can refer its docs for more information. As you already know, Publisher Portal is used to manage the life cycle of APIs such as create, update, deploy, and delete. Similarly, we can…

In this article, I discuss how to enable AWSLambdaMediator and AWS SDK debug logs to monitor AWS Lambda requests/responses — There are two types of logs that you can enable to monitor logs related AWS Lambda function invocation. AWSLambdaMediator logs AWS SDK logs 1. Enabling logs for AWSLambdaMediator AWSLambdaMediator class handles Lambda function invocation using the AWS SDK. It provides some useful logs such as the payload, access method, and status. …

In this article, I discuss how we can modify responses using the http status code and the payload of AWS Lambda responses in WSO2 API Manager — AWS Lambda as an Endpoint feature is very useful when it comes to utilize the benefits of WSO2 API Gateway for AWS Lambda Functions. Now, WSO2 API Manager has limited support for Lambda Proxy Integration and hence, users can pass headers and parameters to Lambda without modifying the payload. …

In this article, I discuss how we can invoke cross-account Lambda functions using WSO2 API Manager 4.1.0 — Latest WSO2 API Manager supports AWS STS AssumeRole to invoke cross-account Lambda functions. Note that this feature is available from 27th July 2022 according to WSO2 APIM docs. 1. Create REST API without an endpoint URL 2. Add AWS Lambda Endpoint