Programming Posts

How to Fix Error “Variable content was trimmed as it was too long” on RHPAM

Just yesterday i got a very unique error,

Variable content was trimmed as it was too long (more than 255 characters)

I can see that this error happens due to RHPAM saves the content of each object on database, but have a 255 character as limitation. And for this case, my object content length is more than 255 characters.

Workaround for this is we need to alter database generated by RHPAM and for example below, im changing it from 255 into 5000 characters.

alter table VariableInstanceLog modify column value varchar(5000);

alter table VariableInstanceLog modify column oldValue varchar(5000);

And need to put below parameter runtime,

-Dorg.jbpm.var.log.length=5000

For a RHPAM deployment on Openshift, we can embed below parameters on RHPAM DeploymentConfig,

	- name: JAVA_OPTS_APPEND
	  value: '-Dorg.jbpm.var.log.length=5000'

Restart RHPAM, and we can see now RHPAM can handle object with length up to 5000 characters.

How to Remove Docker’s Dangling Image on Windows 10

There are times where i need to clean all unused, dangling docker images on my laptop. Previously im running below command,

docker image prune -a

But it seems like altho almost all images are gone, i can see still some images are still occupying my laptop’s disk. So i have to do something to delete them.

The workaround is quite easy, run PowerShell as Administrator and run below command,

docker rmi $(docker images --quiet --filter "dangling=true") -f

Executing that command will generates this log,

And i can see that my harddisk is now have more free spaces πŸ™‚

Integrating Spring Boot Login with Keycloak or Red Hat Single Sign On

When we are managing many applications, one of the most painful part is managing its user and access right. Because usually different applications have their own user management, and sometimes each user have different credentials between multiple applications.

We can solve this problem by having a one point user management where other application can use this tools for managing their user authentication and authorization. This is where Red Hat Single Sign On (or its opensource product, Keycloak) can comes in handy. It provides an end to end user management lifecyle, from activating a new user, managing them, assigning their access right until deactivating them. On this example, we’ll start with a simple login page by using Keycloak, and how other application (in this example is a Spring Boot app) is connecting to it.

First we need to create a java project with below pom file, im using keycloak-adapter bom and keycloak-spring-boot-starter library for this.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.edw</groupId>
    <artifactId>spring-boot-and-rhsso-otp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>war</packaging>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.6.RELEASE</version>
        <relativePath/>
    </parent>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.keycloak.bom</groupId>
                <artifactId>keycloak-adapter-bom</artifactId>
                <version>9.0.2</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.keycloak</groupId>
            <artifactId>keycloak-spring-boot-starter</artifactId>
            <version>9.0.2</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

And perhaps the most important part in this project is, the application.properties. In here, we are putting our Keycloak’s url, realm name, client name, and secret. Also we are defining that only user with admin role can access a URL with /admin/ pattern.

### server port
server.port=8080
spring.application.name=Spring Boot with RHSSO Login

### rhsso configuration
keycloak.auth-server-url=https://rhsso/auth/
keycloak.realm=my-realm
keycloak.resource=my-client
keycloak.public-client=false
keycloak.bearer-only=false
keycloak.principal-attribute=preferred_username
keycloak.credentials.secret=11111111-1111-1111-1111-111111111111

### spring boot ui configuration
spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp

### authorization
keycloak.security-constraints[0].authRoles[0]=admin
keycloak.security-constraints[0].securityCollections[0].patterns[0]=/admin/*

Next is we need to create a user and role on Red Hat SSO,

After that, we need to create a client and its password,

And put those corresponding values inside application.properties.

We can test whether configuration works well or not by directly accessing to admin page (/admin/index). A successful configuration would prevent an unauthorized user from accessing admin page by showing a Keycloak login page. Admin page only accessible once a user has successfully login thru Keycloak or Red Hat Single Sign On.

Full code can be downloaded on my github page,

https://github.com/edwin/spring-boot-and-rhsso

Have fun with RHSSO and Keycloak (H)

Fixing “SSL routines:tls_process_ske_dhe:dh key too small” on Containerized RHEL8

I have a very unique error today, so basically my RHEL 8 (Red Hat Enterpise Linux) cannot connect to another system due to SSL issue. The exception is quite clear, and can be seen below.

error:141A318A:SSL routines:tls_process_ske_dhe:dh key too small

It is quite easy to do it in a standalone infrastructure, but this problem happen on a containerized application which make it much more complicated.

After searching for a solution, i come up with this Dockerfile

FROM registry.redhat.io/application/application-rhel8:7.8.0

user root
RUN update-crypto-policies --set LEGACY 

user 185

Build it,

docker build -f Dockerfile -t application-rhel8-modified:7.8.0 .

Deploy it, and i can see that the previous error is no longer exist.

Tracing Red Hat Fuse Transaction with Jaeger

Jaeger is open source software for tracing transactions between distributed services. It’s used for monitoring and troubleshooting complex microservices environments. And in this example, im trying trying to use it for tracing http request on Red Hat Fuse, or its opensource version which is Apache Camel. The purpose is to see how much time is needed for each api to take, and what kind of information comes with it.

First lets start by installing Jaeger on your local,

docker pull jaegertracing/all-in-one:1.19

docker run -d --name jaeger -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
		-p 5775:5775/udp -p 6831:6831/udp -p 6832:6832/udp -p 5778:5778 \
		-p 16686:16686 -p 14268:14268 -p 14250:14250 -p 9411:9411 \
		jaegertracing/all-in-one:1.19

And create a java project with this pom file,

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.edw</groupId>
    <artifactId>camel-with-jaeger</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <fuse.version>7.2.0.fuse-720020-redhat-00001</fuse.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.jboss.redhat-fuse</groupId>
                <artifactId>fuse-springboot-bom</artifactId>
                <version>${fuse.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-http-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-servlet-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-sleuth</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zipkin</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

    </dependencies>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.jboss.redhat-fuse</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>${fuse.version}</version>
                </plugin>
            </plugins>
        </pluginManagement>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

Set connection to Jaeger tracing

# The Camel context name
camel.springboot.name=camel-with-jaeger

# enable all management endpoints
endpoints.enabled=true
management.security.enabled=false
camel.component.servlet.mapping.contextPath=/api/*
logging.level.root=info

# name for tracing
spring.application.name=Camel Hello World
spring.zipkin.base-url=http://localhost:9411/
spring.zipkin.enabled=true
spring.zipkin.sender.type=web
spring.sleuth.enabled=true
spring.sleuth.sampler.probability=1.0

Create a simple helo-world api,

<?xml version="1.0" encoding="UTF-8"?>
<rest path="/hello-world" xmlns="http://camel.apache.org/schema/spring">
    <get>
        <route>
            <setHeader headerName="Content-Type">
                <constant>application/json</constant>
            </setHeader>
            <setBody>
                <simple>{ "hello": "world" }</simple>
            </setBody>
        </route>
    </get>
</rest>

We test our newly created api by using curl command,

curl -kv http://localhost:8080/api/hello-world

And the result can be viewed directly on Jaeger dashboard


Now lets say we have other requirement such as adding a specific information on every trace result on Jaeger. We can achieve that by using Tag inside current Trace Span.

package com.edw.routes;

import org.apache.camel.Exchange;
import org.apache.camel.builder.RouteBuilder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.sleuth.Span;
import org.springframework.cloud.sleuth.Tracer;
import org.springframework.stereotype.Component;

@Component
public class HelloWorldRoute extends RouteBuilder {

    @Autowired
    private Tracer tracer;

    @Override
    public void configure() throws Exception {
        rest()
                .get("hello")
                .route()
                .setHeader(Exchange.HTTP_RESPONSE_CODE, simple("200"))
                .setHeader(Exchange.CONTENT_TYPE, simple("application/json"))
                .process(exchange -> {
                    Span span = tracer.getCurrentSpan();
                    span.tag("something", "whatever");
                    span.tag("pretending to do some queries", "select 1 from dual");
                })
                .setBody(constant("{\"world\":\"world\"}"))
                .endRest()
        ;
    }
}

The result would be displayed on every trace like this,

Full code for this tutorial can be accessed in below url,

https://github.com/edwin/fuse-with-jaeger

Have fun with Jaeger and Camel πŸ™‚