If you define the mail resource directyl in your domain.xml file take care about the ‘resource-ref’ declaration in the seciton ‘<servers>’. If you miss this, than your application will not find the mail resource to be injected!
The Payara project provide a well maintained docker image on Docker Hub. Since version 5.192 you can easily create a docker image which runs Payara in Debug mode. You need just to add the environment variable “PAYARA_ARGS”
ENV PAYARA_ARGS --debug
COPY my-example.war $DEPLOY_DIR
Or you can also set the environment in your docker-compose.yml file:
Running a Apache Cassandra Cluster with Docker-Swarm is quite easy using the official Docker Image. Docker-Swarm allows you to setup several docker worker nodes running on different hardware or virtual servers. Take a look at my example docker-compose.yml file:
I am running each cassandra service on a specific host within my docker-swarm. We can not use the build-in scaling feature of docker-swarm because we need to define a separate data volume for each service. See the section ‘volumes’.
The other important part are the two environment variables ‘CASSANDRA_BROADCAST_ADDRESS’ and ‘CASSANDRA_SEEDS’.
‘CASSANDRA_BROADCAST_ADDRESS’ defines a container name for each cassandra node within the cassandra cluster. This name matches the service name. As both services run in the same network ‘cluster_net’ the both cassandara nodes find each user via the service name.
The second environment ‘CASSANDRA_SEEDS’ defines the seed node which need to be defined for the second service only. This is necessary even if a cassandra cluster is ‘master-less’.
The new Open Source E-Mail Client Mailspring is possible an alternative for your Thunderbird. I am running Linux Debian and there are not so much different mail clients available. Mailspring seems to become more and more interesting.
How to Install Mailspring on Linux Debian
To install mailspring on Linux Deiban first download the latest .deb package from the Download page. To install the client run:
In this Blog I will show you how we use Apache Cassandra in our Open Source Project Imixs-Archive. Imixs-Archive is a service which we use inImixs-Workflow to push business data into a Cassandra Cluster. The service provides a Rest API based on JAX-RS and uses the DataStax Driver to write the data into the Cassandra Cluster.
The problem is that for a connection you need first to setup a Cluster Object and connect to your keyspace to get a Session object. This is time consuming and slows down the rest service call if you do this during the request. But within Java EE you can solve this problem easily
With the new Microprofile-Config API there is a new and easy way to deal with configuration properties in an application. The Microprofile-Config API allows you to access config and property values form different sources like:
all META-INF/microprofile-config.properties files
You can find a good introduction into the Microprofile Config API here. And of course your can also implement your own config source. But most of the examples are based on reading custom config values from am existing file, like in the example here. Now in this Blog I will show how you can implement a Micorprofile ConfigSource based on values read from a Database.
Today I installed the GitLab Community Edition on Docker. It takes me some time to figure out how to get it done in an reasonable way. On the GitLab pages there is an installation guide for Docker. And the Docker images for GitLab are very well maintained on DockerHub. In the following I will expalin how to run GitLab with Docker-Compose and separate Database Containers.
I started to run our Imixs-Workflow engine on Open Liberty Application Server. One important thing in Imixs-Workflow is the authentication against the workflow engine. In Open Libertry, security can be configured in the server.xml file. But it takes me some time to figure out the correct configuration of the role mapping in combination with the @RunAs annotation which we use in our service EJBs.
In this example I use tags to specify variants of the same metric name. With MP Metrics 2.0, tags are used in combination with the metric’s name to create the identity of the metric. So by using different tags for the same metric name will result in an individual metric output for each identity.
But in case you want to create a custom metric with custom tags you can not use annotations. This is typically the case if the tags are computed by application data at runtime. The following example shows how you can create a metric with tags programatically: