Tag Archives: Oracle

GraalVM – why a different VM?

09 Thursday Aug 2018

Posted by in development, General, Oracle, Technology

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If you read press around Java you’ll have come across references to GraalVM. So what is it and why would I use it?

There is an excellent podcast from Software Engineering Daily that digs into the subject and can be found here and here. But let draw out some of the reasons as to why GraalVM is interesting.

Whilst multiple languages on top of the JVM is nothing new, such as Scala , Kotlin, and Groovy to name a few, GraalVM through the use of its Truffle framework takes it a new level. Truffle provides an Abstract Syntax Tree (AST) which describes the language syntax (more here about AST). The net result is any language can be described and therefore executed using the GraalVM. To this end the GraalVM team have got Node and JavaScript ported in addition to defining existing languages using this approach. Not all of this is proven robustly in production, but some of the languages VM certainly is, for example Twitter have been using the Scala port.

Because the languages are described through the same framework this means the work to optimise the VM performance becomes a lot easier.

It would be easy to assume that using the framework would mean the execution of languages using this mechanism would slow be slower. But, Truffle works by translating the code to standard byte code before execution, so ‘ported’ languages are now no less efficient than Java come runtime.

There is an interesting bi-product of this model, that at runtime with the right object exposures it is possible for multiple languages to interact with the same object easily, no JNI or dropping to the lowest common denominator such as a JSON+REST. This does raise interesting possibilities for thick client solutions or polyglot monoliths!

Probably one of the biggest pay offs for using GraalVM and its ability to run multiple languages is that the base Container images can be simplified as you don’t need different container images. This makes the work of patching and testing configurations of these container a lot simpler as the permutations will drop, particularly for organisations that have wholehearted embraced polyglot micro-service ideas.

One common reason for changing implementations of the JVM particularly at the more performance sensitive use cases (checkout Azul as an example) is how the JVM is optimised and the JIT algorithms and processes particularly the Garbage Collector work (checkout this list of JVMs. For example GraalVM will provide better performance for processes that less heap hungry than Oracle’s JVM.

It is interesting that Oracle are investing in a new VM when it wasn’t that long ago that JRockit was wound down. Given the legal dispute between Oracle and Google (see here) the new VM would give Google a means to escape from the copyright breaches and retain support for Java.

Oracle Podcasts – Beer & Pizza

18 Monday Jun 2018

Posted by in Dev Meetup, General, Oracle, Technology

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We have been fortunate enough to participate an ArchDev podcast about meetups – https://oracledevs.podbean.com/e/pizza-beer-and-dev-expertise-at-your-local-meet-up/

The podcast talks about the differences between the meet-ups and events such as conferences, what we try to get out of a meetup and the effort put into arranging them.

For more info about the meetup I help organise checkout out https://www.meetup.com/Oracle-Developer-Meetup-London/events/249256400/

We’d also like to thankyou Jurgen Kress and his team for all the behind the scenes work that means the London Dev Meetup events can happen and ensure all are suitable feed and watered.

Oracle Code London – Presentation & Periscope Interview

31 Thursday May 2018

Posted by in General, Oracle, Technology

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Whilst in London Wednesday to present Microservices in a Monolith World at the Oracle Code London,  I also participated in an interview streamed via Periscope.  The interview can be seen at https://www.pscp.tv/w/1jMKgqBrwYyJL 

Not only was this interview captured, my entire presentation is available on YouTube …

Lessons in Oracle Cloud Password Management

07 Monday May 2018

Posted by in General, Oracle, Technology

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Oracle Cloud is growing and maturing at a tremendous rate if the breadth of PaaS capabilities is any indication.  However, there are a few gotchas out there, that can cause some headaches if they get you. These typically relate to processes that impact across different functional areas. A common middleware stack (API CS, SOA CS, OIC etc) will look something like the following:

cloudPassword

As the diagram shows when you build the cloud services, the layers get configured with credentials to the lower layers needed (although Oracle have in the pipeline the Oracle managed version of many services where this is probably going to be hidden from us). Continue reading →

Oracle Dev Meetup

24 Tuesday Apr 2018

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Another month and another Meetup.  Last night was the quietest session we’ve had. But then we covered Identity Management and whilst the subject is so important it isn’t too popular.

Tanks to Atul Kumar for taking on the task of presenting on this subject.  You can find out more about Atul at:

The content covering use of Messaging Cloud and our drone project can be seen here:

Successful PaaS Team

17 Saturday Mar 2018

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39919340285_bde0aacde1_zLast week we attended the Oracle EMEA PaaS Forum in Budapest. I have to say we’re proud to be part of a team that has picked up two conference awards.  Firstly our CTO Luis Weir for Contributions to API Solutions and then the wider team have collected an award for overall Outstanding PaaS Contributions.

40823835111_5b00f7963e_z

L-R, me, Amy Grange, Soham Dasgupta (Capgemini Netherlands), Luis Weir (Oracle Delivery Unit CTO), Jurijs (Yury) Fjodorovs

Some photos from the trip can be found a here.

Managing API Policy Versioning in Oracle API Platform

27 Tuesday Feb 2018

Posted by in API Platform CS, APIs & microservices, Books, General, Oracle, Technology

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Oracle’s API Platform (API-P) product avoids the use of external configuration management. If you want to better understand why, then checkout our forthcoming book as it goes into detail about why this is the case (it can be pre-release version of the book can be obtained here). In a previous blog I wrote about and illustrated the use of the API-P’s own APIs so that it was possible to see what API iterations had been deployed to API Gateways.

In this blog I want to explore the issues of version management a bit further. API-P provides internal version management through the idea of iterations as previously explored (Understanding API Deployment State on API Platform). In addition to this there are API policy attributes called version, status etc. This information whilst having some impact on behavior reflects the version of the ‘contract’ that the API represents between the consumer and provider, and requires a manual change.

The API policies themselves are version tracked through the iteration identifiers. Each time a policy is saved the iteration is is incremented. What the API-P doesn’t support is the concept of branching. In relatively simple API Policy branching is unlikely to ever be an issue.

Why is a reversion capability needed?

Let’s take a more complex scenario.  In our book API Platform we introduced the some APIs that would allow the retrieval of meta data about artists in the record companies’ catalog. It has however come to light that the API has been targeted with malicious calls, firstly through trying to attack using injection attacks and secondly trying to overload the back end by creating data requests that make the back-end work hard in retrieving data.

To defend against this, the API Policy has been enhanced to include some custom groovy policies to inspect the values provided. Strictly speaking following the principles of Semantic Versioning the API version should go from 1.0.0 to 1.0.1. However seeing that the ‘contract’ as presented to the consumer hasn’t really changed – the data models are the same, the URI goes unaltered resulting in the implementation team not changing the version.

During development processes, it is not unusual to be developing existing logic, and decide that approach being used isn’t right or not going to perform as well. So you abandon your changes and revert back to the last approved version. However, this isn’t possible as any save will result in a new iteration. The API-P will be getting some enhanced version management features. But today to be able to undo the changes we need a means to ‘revert forward‘ (hence the tool name) that is to take an older iteration and make it the latest, as illustrated in the next diagram.

Today the API-P doesn’t provide a means to perform this process within the User interface. However when looking at a gateway you can review the API policy deployed. As we established previously that you may have different gateways deployed with different iterations. Given this, as API-P has been built true to the principles of separating the UI from the backend through the use of APIs we can deduce there should be a means to get the details of an API with a specific iteration.

To this end we have built on the pattern previously illustrated to provide the means to ‘Revert Forward’ by creating a Groovy script that will use the APIs provided by API-P to retreive an iteration and push it back at the latest version. When the policy is pushed back it also modifies the description to show which iteration has been pushed.

You may ask, why not use the conventional developer approach of branching as suggested in the following diagram. However API-P’s iteration framework doesn’t extend to support this.

The next with this is pretty predictable – how do I know which iteration to revert to. You have two options here, firstly either revert in order so you can see the prior version in turn – which whilst visually good, is not necessarily the most practical option. So in the tool we have a parameter that will allow you to display on the console the configuration of each iteration. This does mean you are going to see the policies in a JSON presentation. To make life easier we would recommend good practise and recording in the policy description information that helps determine the policy’s characteristics – and this can be used to better determine iteration behaviour.

If we are able to take an earlier iteration and make it the latest one by pushing it back then it is a short step to actually target a different management cloud in effect migrating the policies. Whilst possible it comes with some serious cautions …

  • You risk undermining your version management, which management cloud has the master, and the iteration numbers will NOT migrate so it’s not like this info can be used to distinguish the laster version
  • The logic included doesn’t accommodate handling differences in policy versions – so if trying move between instances of the API Platform they need to be the same version otherwise your configuration could make a mess of thing
  • This issue is further compounded if you are deploying custom Java policies.
  • Environment specific policies simply won’t work for example gateway based routing.

Oracle does not recommend that the policies be stored anywhere outside of the platform, whilst it this utility makes that a possibility, it deliberately avoids writing any of the information to the file, the policies only reside outside of the platform for the duration of the process execution.

The Tools Commands

All the parameters assume the values will not contain any space characters. Each command is preceded by a dash eg. revertForward.groovy -inpassword mypass -inSvr https://a.b.com

  • -h or -help – provides this information
  • -inName – user name to access the source management cloud
  • -inPass – password for the source management cloud
  • -inSvr – The server address without any attributes e.g. https://1.2.3.4
  • -policy – numeric identifier for the policy of interest
  • -iter – iteration number of interest for the policy – optional
  • -outName – optional, the target management cloud username, only needed for migrations
  • -outPass – optional, the target management cloud password, only needed for migrations
  • -outSvr – optional, the target management cloud server address – same formatting as inSvr, only needed for migrations
  • -override – optional, if migrating to another management, tells the script to replace the existing policy of the same name if found
  • -view – optional, separate command to allow viewing of the policy – requires one of the following values:
    • display – displays all the details of the policy, if no iteration is provided this will be the latest iteration
    • summary – provides the headline information of the policy including name, change date etc
    • summary-all – summarizes all the iterations from the current one back to the 1st
  • -debug – optional, will get script to report more information about what is happening

The code can be obtained from my GitHub repository here.

Validating API Platform Policies & Gateway Deployments

01 Thursday Feb 2018

Posted by in API Platform CS, APIs & microservices, General, Oracle, Technology

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When configuring API Policies in the the Oracle API Platform it helps if there is a simple back end that can take the received payload and record the sent values (header & body) as well as reflect the call details back as the response, or possibly respond with a test payload (so that response policies, particularly policies that require payload navigation  can be exercised correctly).  By having this facility it becomes a lot easier to determine whether the policies are executing correctly in terms of routing, transforming, filtering etc. without needing to worry about whether the API implementation is correct. You could say that this is a kind of mock for testing the API Platform.

The added benefit of having a mock back end is that it is easy to ‘smoke test’ a gateway deployment very easily.  Particularly if the mock is happy to receive any form of call.

Whilst implementing such a capability can be done in pretty much any language and platform you like.  We have in the past for example built a Springboot Java application that can have the dependencies configured to then deploy into WebLogic for example.  We have come to refer these test apps/mocks as PlatformTests as that’s exactly what they help do. A Node.js implementation of a PlatformTest such as as the following implementation is particularly appealing as the Node.js footprint is small and simple to deploy and undeploy. A basic Node.js implementation can also consume any URL and operation you choose to use. The nature of JavaScript makes it very quick to adapt the mock if need be. Although in the ideal world, we write the solution once and then use simple configuration to tune behavior.

The following code looks for a local file called testResponse.json if found then returns the content of the file (assumed to be JSON) otherwise it reflects back in the body, the received header and body.  This reflection makes it extremely easy to see how the policies have changed the inbound call.  The content is also logged to the console – making it easy to also see what came through to the back end.

The implementation also assumes port 8080, but changing the port is exceptionally easy.

There one enhancement planned, and this is to allow the response test payload to be handled as XML.  This will need a little tweaking of the code as presently a JSON Object is currently stringified.

JavaScriptThe code is also available in my GitHub repository – https://github.com/mp3monster/Utils/blob/master/PlatformTest.js and an example test response file is at https://github.com/mp3monster/Utils/blob/master/testResponse.json

const http = require('http');
const fs = require('fs');

// create a simple HTTP server that will handle the requests
http.createServer((request, response) => {
const { headers, method, url } = request;
console.log("Called at " + new Date().toLocaleDateString());
let body = [];
request.on('error', (err) => {
console.log("Svr Error Handler :" + err.toString);
response.statusCode(400);
response.end();
}).on('data', (chunk) => {
body.push(chunk);
}).on('end', () => {
body = Buffer.concat(body).toString();
// At this point, we have the headers, method, url and body, and can now
// do whatever we need to in order to respond to this request.

});

// record in the console what details have been received
console.log ("Received:\nMethod:" + method.toString() +
"\n URL:"+ url.toString + "\nheaders:\n"+headers.toString() +
"\nBody:\n" + body);
// now build the response
response.setHeader('Content-Type', 'application/json');
response.setHeader('PlatformTestTime', new Date().toLocaleDateString());

// initialise our response object so that if we don't load a response
// file then we reflect the content
var responseBody = { headers, method, url, body };

try {
// try reading a response file
fs.readFile('testResponse.json', function(err, data) {
console.log("handling file");
if (err != null) {
if (err.code === 'ENOENT') {
console.log("on return file - will reflect");
} else {
console.log("Read error:" + err.toString());
}
} else {
// a file exists - but is empty?
if ((data != null) && (data.length > 0)) {
// we have a file with content - lets process so it into a JSON
// object
if (Buffer.isBuffer(data)) {
// convert the buffer from hex to an ASCII string
body = data.toString('utf8');
console.log("test response:" + body);
responseBody = JSON.parse(body);
}
}
}

// create an array with our values and then make it

// JSON with stringfy

var output = JSON.stringify(responseBody);
response.write(output);
console.log("Returning:" + output);
response.statusCode = 200;
response.end();

});

} catch (err) {

if (err.code === 'ENOENT') {
console.log("on return file - will reflect");
} else {
console.log(err.toString());
}
var output = JSON.stringify(responseBody);
response.write(output);
console.log("Returning:" + output);
response.statusCode = 200;
response.end();
}
}).listen(8080); // Activates this server, listening on port 8080.