I have some static configurations that will not be changed for each environment, for example, the mapping between client names and their id. In this case, should I store them in a Spring yml property file or in a database, eg. mongoDB, so that they can be easily accessed via Java code?
From the one side, consider that when you are adding a database component, you are adding additional potential point of failure to your app. What will happen if DB will not be accessible, for any reason ? ( crashed, under maintenance, network issues ) ?
From the second side, it depends how exactly your implementation will be using files. For example, if you will be adding items in your mapping between clients/ids, will you need to restart/rebuild/redeploy your app? How many running instances of your app will you have?
So, there are no one exact answer for all cases
It better keep in spring yaml instead of storing in any Database. Because calling the IO operations little expensive . Keeping static code in yaml or properties file will faster to access.
First of all, I am new to Spring Boot so I am not sure if something like this is possible within the framework.
Let me describe my problem.
I have 10 code repositories. Each repository listens to a data stream, parses the data and updates a database. Due to maintainability issues I plan on bringing it under a single code repository. This new application will be generalized, and certain app specific configurations (for example, which stream should I connect to, the database host) will be retrieved at run-time.
Theoretically, this would allow me to maintain a single code base, but deploy it as 10 separate services based on configurations which is what I need. However, there's a set of java classes that are application specific used to parse the retrieved data. To better understand this refer the diagram below.
Ideally, I need to still maintain these classes in the same repository, but as separate modules. Once the configurations are loaded, the app should be able to load the corresponding module into the application context and initialize the Java classes. The other modules will not be used.
Can I do something like this with Spring Boot? Alternately, even a build time solution is fine if I can create separate builds which can then be deployed separately.
Not sure did I understood it well but why don't try spring profile (https://www.baeldung.com/spring-profiles). You can set for every service different config and with spring.profiles.active in runtime say what configuration will use.
Also something like this could be useful https://www.baeldung.com/spring-reloading-properties
We have a Spring web app which is behind nginx balancer. A need occurred to change some properties at runtime, preferrably without redeployment/restart.
However, a simple in-memory way like a controller which changes the value doesn't solve the problem because the balancer will send it to one specific server and others will have old property value.
This property change feature is a tool for support team and is not expected to be used often.
We came up with next ideas:
Controller + field in the database which holds actual value. However, in this case we will need to always query the DB for actual value.
Controller + curl script + list of actual servers, not the balancer. Will do the job, but very error-prone in future.
Forget the idea and just redeploy the app changing the properties file manually.
Maybe there's something else?
No code is available yet, it's more like a design question.
We build 3-tier enterprise solutions that typically consists of several webapp and ejbjar modules that all talk to a db and have several external integration points.
Each module typically needs its own configurations that can change over the solution's life time.
Deploying it becomes a nightmare because now we have 18 property files that must be remembered to copied over and configured also setting up data-sources, queues, memory requirements etc.
I'm hopeful but not optimistic that there can be a better way.
Some options we've considered/used, each with it's pros and cons:
Use multiple maven projects and continuous integration (eg. hudson or jenkins) to build a configuration jar that includes all the property files for each environment (dev, qa, prod) and then bundle everything up as an EAR. But then things can't be easily changed in production when needed.
Put most of the settings in the DB and have a simple screen to modify it. Internally we can have a generic configuration service EJB that can read and modify the values. Each module can have a custom extended version that have specific getters and setter.
Version control all the property files then check it out on production and check it into a production branch after making changes.
With all of these you still need to configure data-sources and queues etc. in a container specific way :(
Сonsider binding a custom configuration object to JNDI. Then lookup this object in your apps to configure them. Benefits - you can use custom configuration object instead of rather generic Map or Properties.
Another way is to use JMX to configure applications you need. Benefits - you can bind objects you have to configure directly to MBean Server and then use such a well-known tools as jconsole or visualvm to configure components of your application.
Both ways support dynamic reconfiguration of your applications at runtime. I would prefer using JMX.
I've gone through several cycles of finding ways to do this. I still don't have a definite answer.
The last cycle ended up with a process based on properties files. The idea was that each server instance was configured with a single properties file that configured everything. That file was read by the startup scripts, to set memory parameters, by the app server, and by the application itself.
The key thing, though, was that this file was not managed directly. Rather, it was a product of the build process. We had a range of files for different purposes, kept in version control, and a build step which merged the appropriate ones. This lets you factor out commonalities that are shared along various axes.
For example, we had development, continuous integration, QA, UAT, staging, and production environments, each with its own database. Servers in different environments needed different database settings, but each server in a given environment used the same settings. So, there was something like a development-db.properties, qa-db.properties, and so on. In each environment, we had several kinds of servers - web servers, content management servers, batch process servers, etc. Each had JVM settings, for heap size and so on, that were different to other kinds of servers, but consistent between servers across environments. So, we had something like web-jvm.properties, cms-jvm.properties, batch-jvm.properties, and so on. We also had a way to have overrides for specific systems - production-cms-jvm.properties sort of thing. We also had a common.properties that set common properties, and sensible defaults which could be overridden where needed.
Our build process was actually a bit more complicated than just picking the right options from each set; we had a master file for each server in each environment which specified which other files to include. We allowed files to specify other files to include, so we could build a graph of imports to maximise reuse.
It ended up being quite complicated. Too complicated, i think. But it did work, and it did make it very, very easy to make changes affecting many servers in a controlled way. We even merged a set of input files from development, and another from operations, which contained sensitive information. It was a very flexible approach.
I know this has already been answered and my answer is not necessarily generic, but here's my take on things:
Note, here I'm only considering system/resource properties, not application settings. In my view, application settings (such as a payment threshold or other settings should be stored in a database, so that the system can be reconfigured without having to restart a service or cause downtime by re-deploying or re-reading a properties file).
For settings that impact on how different parts of a system connect with each other (such as web service endpoints, etc), I would make use of the JNDI tree.
Database connectivity and JMS connectivity would then be set-up using the Websphere console and can be managed by the Websphere administrators. These can also be created as JACL scripts which can be put into version control if necessary.
In addition to the JNDI resources, for additional properties, such as usernames for web service calls to a backend, etc, I would use Websphere "Name Space Bindings". These bindings can be edited using the Websphere console and accessed via JNDI using the "cell/persistent/mypassword" name.
So I could create the "mypassword" binding (a string), and the management for it falls to the Websphere admin (away from developer eyes or other people who should not have access to production systems), while the same EAR file can be used on dev, test, preproduction and production (which is preferable to have different EAR files for different systems, as the likelihood of other differences creeping in is reduced).
The Java code would then use a simple JNDI lookup (and possibly cache the value in memory).
Advantages over properties files:
Not having a "vulnerable" file that would need to be secured because system properties contain passwords.
Not having to add Java security policies to allow access to that file location
Advantages over database properties:
Not tied to having one database tied to an application server.
Hope that helps
Use multiple maven projects and continuous integration (eg. hudson or
jenkins) to build a configuration jar that includes all the property
files for each environment (dev, qa, prod) and then bundle everything
up as an EAR. But then things can't be easily changed in production
when needed.
I think the config should be in the database of the application instance. Your local machine config may be diffrent to dev and to QA, PROD , DR etc.
What you need is a way of getting the config out the database in a simple way.
I create a separate project with a provided dependency of Apache commons-configuration
It has many ways of storing data, but I like databases and the configurations lives in the database environment.
import javax.sql.DataSource;
import org.apache.commons.configuration.DatabaseConfiguration;
public class MYConfig extends DatabaseConfiguration {
public MYConfig(DataSource datasource) {
super(datasource, "TABLE_CONFIG", "PROP_KEY", "PROP_VALUE");
}
}
Put most of the settings in the DB and have a simple screen to modify
it. Internally we can have a generic configuration service EJB that
can read and modify the values. Each module can have a custom extended
version that have specific getters and setter.
Commons configurations as a simple API, you may then write the GUI as you wish.
You can do the interface in anyway you wish. Or as a quick win have no interface.
Version control all the property files then check it out on production
and check it into a production branch after making changes.
Version control is great. Add another DatabaseConfiguration using composition. The class you extends is the active config and the composed one being the audit. There is another constructor can can have a version. Just overload the right methods to get the desired effect.
import javax.sql.DataSource;
import org.apache.commons.configuration.DatabaseConfiguration;
public class MYConfig extends DatabaseConfiguration {
final DatabaseConfiguration audit;
public MYConfig(DataSource datasource) {
super(datasource, "TABLE_CONFIG", "PROP_KEY", "PROP_VALUE");
audit = new DatabaseConfiguration("TABLE_CONFIG_AUDIT", "PROP_KEY", "PROP_VALUE");
}
#Override
public void addProperty(String key, Object value) {
Object wasValue = super.getProperty(key);
super.addProperty(key, value);
audit.put(key,wasValue);//add version code
}
}
http://commons.apache.org/proper/commons-configuration/
User a simple database table (Section, Key, Value). Add "Version" if you need it, and wrap the entire thing in a simple ConfigurationService class with methods like getInt(String section, String key)
Not a lot of work, and it makes the application code very neat, and tweaking with the configuration very easy.
Interesting alternative config file format: write a scala trait. Your config file can then just be a scala file that you compile and evaluate when the server starts.
http://robey.lag.net//2012/03/26/why-config.html
There is a team develops enterprise application with web interface: java, tomcat, struts, mysql, REST and LDAP calls to external services and so on.
All configuration is stored in context.xml --tomcat specific file that contains variables available via servlet context and object available via JNDI resources.
Developers have no access to production and QA platforms (as it should be) so context.xml is managed by support/sysadmin team.
Each release has config-notes.txt with instructions like:
please add "userLimit" variable to context.xml with value "123", rename "DB" resource to "fooDB" and add new database connection to our new server (you should know url and credentials) named "barDb"
That is not good.
Here is my idea how to solve it.
Each release has special config file with required variable names, descriptions and default values (if any): even web.xml could be used.
Here is pseudo example:
foo=bar
userLimit=123
barDb=SET_MANUAL(connection to our new server)
And there is a special tool that support team runs against deployment artifact.
Look at it (text after ">" is typed by support guy):
Config for version 123 of artifact "mySever".
Enter your config file location> /opt/tomcat/context/myServer.xml
+"foo" value "bar" -- already exists and would not be changed
+"userLimit" value "123" -- adding new
+"barDb"(connection to our new server) please type> jdbc:mysql:host/db
Saving your file as /opt/tomcat/context/myServer.xml
Your environment is not configured to run myServer-123.
That will give us ability to deploy application on any environment and update configuration if needed.
Do you like my idea? What do you use for environment configuration management? Does there is ready-to-use tools for that?
There are plenty of different strategies. All of them are good and depends on what suit you best.
Build a single artifact and deploy configs to a separate location. The artifact could have placeholder variables and, on deployment, the config could be read in. Have a look at Springs property placeholder. It works fantastically for webapps that use Spring and doesn't involve getting ops involved.
Have an externalised property config that lives outside of the webapp. Keep the location constant and always read from the property config. Update the config at any stage and a restart will be up the new values.
If you are modifying the environment (i.e. application server being used or user/group permissions) look at using the above methods with puppet or chef. Also have a look at managing your config files with these tools.
As for the whole should devs be given access to prod, it really depends on a per company basis. For smaller companies where the dev is called every time there is a problem, regardless of whether that problem is server or application related, then obviously devs require access to the box.
DevOps is not about giving devs access to the box, its about giving devs the ability to use infrastructure as a service, the ability to spawn new instances with application X with config Y and to push their applications into environments without ops. In a large company like ours, what it allows is the ability for devs to manage the application they put on a server. Operations shouldn't care what version is on their, thats our job, their job is all about keeping the server up and running.
I strongly disagree with your remark that devs shouldn't have access to prod or staging environments. It's this kind of attitude that leads to teams working against each other instead of with eath other.
But to answer your question: you are thinking about what is typically called continuous integration ( http://en.wikipedia.org/wiki/Continuous_integration ) and moving towards devops. Ideally you should aim for the magic "1 click automated deployment". The guys from Flickr wrote a lot of blogs (and books) about how they achieved that.
Anyhow .. there's a lot of tools around that sector. You may want to have a look a things like Hudson/Jenkins or Puppet/Chef.