Tag Archives: Oracle

API Caching with the Oracle API Platform

01 Friday Feb 2019

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

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We have been developing some advanced custom API policies for a client and in the process picked up on a few insights that didn’t even make into the API book. One of these policies is to provide an optimization around caching of API calls. The rest of this blog will talk about the tricks we have specifically applied to link an API Gateway to a caching mechanism and why.

Before I go into the details, I’d like to thank the Oracle product management team and particularly Glenn Mi at Oracle for their support getting through the deeper undocumented elements of the capabilities of the API Platform SDK.

Caching Options

Caching comes in may forms, and is motivated by varying reasons and not always the wanting the same behaviours. When getting into the subject of caching it is surprising how polarised people’s view points can be about which cache strategies are correct. The following diagram illustrates the diversity of caches that could appear in an end to solution solution.

Bringing together a caching technology in the Reverse Proxy model and an API Gateway makes a lot of sense. Data being provided to API consumers needs to be protected whether it comes from a cache or an active back-end system. At the same time you also want to exploit an API Gateway to provide analytics on API traffic, so any caching needs to be behind the gateway. But, if In front of an application layer then we can reduce the application workload.

When it comes to caching technology to partner with the gateway, there are a number of options available from Coherence to ehCache, memcache and Redis. We have avoided Coherence, whilst the gateway currently runs on a WebLogic server, we don’t want to need to unduly distort the performance profile and configuration of the Gateway by forcing a cache onto that server. In addition to which as Coherence is a licensed addition to WebLogic it raises difficult questions about licensing when deploying gateways (with gateways licensed based on logical groupings and API volumes but Coherence is licensed by OCPU). We also know that Oracle is moving towards having a micro-gateway which may mean we see the gateway engine moved onto something like Helidon (but this last point is my speculation).

We have elected to use Redis for several reasons –

  • Available as a PaaS service with several cloud providers (AWS & Azure) so no setup or management effort but can also be deployed on-premises,
  • Has an out of the box deployment that means cached entities can have a time to live (TTL) rather than needing to implement separate processes to expire cached values,
  • The ability to make it scale through clustering,
  • Cost

This caching model also allows us to optionally allow application development teams to push into the cache directly results. So rather than waiting on TTL the cache can be refreshed directly or even primed, rather than having to create fake requests to prime a cache.

Custom Policy

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Exploring Helidon – Part 1

01 Tuesday Jan 2019

Posted by in General, Helidon

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So I recently blogged (here) about the announcement of Helidon – the open source project from Oracle to provide a microservice app server that includes optional support for the J2EE Microprofile.

This is the first of what will probably become a series of blogs about Helidon, particularly in its SE form (non J2EE Micro-Profile) as Micro Profile and the wider J2EE model in general will have been documented more widely.

Hello World

Helidon comes with a quick start example app implemented both in SE and MP forms.  It is worth following the very simple instructions provided by the Helidon site to instantiate both versions of the Hello World app as it provides a good way to start to understand the differences in the way Helidon can be used.

The thing that really jumps out when you compare the code (for me at least) is the fact that the SE code being driven from values loading from configuration is more dynamic. The configuration can be sourced in a number of different ways from YAML files to etcd.So for our for first experiment we took the hello World app, and made the path /greet dynamic by loading the path from from some additional configuration. Enhancing the main with :

private static Routing createMultiRouting() {
Map greetingConfig = Config.create().get(“greeting”).asMap();
Routing.Builder routing = Routing.builder();
if (!greetingConfig.isEmpty())
{
greetingConfig.forEach((k,v)->
{
System.out.println (“Read config value>” + k + “=” + v + “<“);
// as the key is the fully qualified name, I just want the last piece,
// so let’s strip it to be a substring
String key = (String)k;
key = key.substring(key.lastIndexOf(“.”)+1);
// each different URI should have its own instance of the Greet Service
// with its tailored key which will mean it responds with the key e.g. France
routing.register(JsonSupport.get())
.register(“/”+v, new GreetService(key));
});
}
else
{
System.out.println(“No config\n”);
}
return routing.build();
}
 

We can create URLs for greetings in different languages, and see the different instances of the Service object responding to the web calls. Whilst many may associate this approach with Node.js for me it felt more like the webserver multiplexer (MUX) such as Gorilla used with Go (you can see what I mean here).

Helidon and On the Road

Two of the leading figures Tomas Langer and Dmitry Kornikov will be presenting at a number of meet-ups in Europe, including the London Meetup (go here)

Part 1?

Yes, I will be blogging more about Helidon as soon as I can, but presently wrapping up a white paper and running an API Design training session soon.

London Oracle Developer Meet-up – November 18

19 Monday Nov 2018

Posted by in development, General

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Another Oracle Developer Meet-up took place in London yesterday. This meet-up focused on Terraform and Microservices. The summary of the evening slides:

Chris Hollies’ slides can be found at here.  As demo’s aren’t included in the deck, the following videos are alternatives:

Our second session, that I presented on how we can establish paths of transition that make it easy to adopt microservices. The presentation material for this is available here:

UK Oracle User Group Annual Conference

01 Thursday Nov 2018

Posted by in General, Technology, UKOUG

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As we rapidly approach the end of the Year.  We’re still pretty busy.  The UK Oracle User Group Annual Conference covering Oracle Technology (Tech18) ranging from Database on premises to Polyglot development in Oracle and other clouds passing through Hybrid Integration, SOA and so on.  Alongside this is also Apps18 which covers Oracle Applications from EBusiness Suite and Seibel to the Fusion cloud solutions such HCM, Financials, Taleo and so on. Then finally the 3rd part covering all things JDEdwards.

tech18

Being on the committee for the conference means that I have been heavily involved in developing the conference agenda and choosing sessions.  So I can say with great confidence that there is a very diverse range of sessions from highly respected SMEs and presenters along with new blood presenting on subjects from Oracle JET to Robotic Process Automation (RPA) for example.

I hope we’ll see you there.

Defining Boundaries for Logical Gateways on the API Platform a multi cloud / multi region context

31 Wednesday Oct 2018

Posted by in API Platform CS, General, Oracle, Technology

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The Oracle API Platform takes a different licensing model to many platforms, rather than on CPU it works by the use of Logical Gateways and blocks of 25 million successful API calls per month. This means you can have as many actual gateway nodes as you like within a logical group to ensure resilience as you like, essentially how widely you deploy the gateways is more of a maintenance consideration (i.e. more nodes means more gateways to take through a maintenance process from the OS through to the gateway itself).

In our book (here) we described the use of logical gateways (groups of gateway nodes operating together) based on the classic development model, which provides a solid foundation and can leverage the gateway based routing policy very effectively.

logical partitions

But, things get a little trickier if you move into the cloud and elect to distribute the back end services geographically rather than perhaps have a single global instance for the back-end implementation and leverage technologies such as Content Delivery Networks to cache data at the cloud edge and their rapid routing capabilities to offset performance factors.

map1

Classic Global split of geographies

Some of the typical reasons for geographically distributing solutions are …

  • Low hit rate on data meaning caching solutions like CDNs are unlikely to yield performance benefits wanted and considerable additional work is needed to ‘warm’ the cache,
  • Different regions require different back end implementations ordering of products in one part of the world maybe fulfilled using a partner, but in another it is directly satisfied,
  • Data is subject to residency/sovereignty rules – consider China for example. But Germany and India also have special considerations as well.

So our Global splits start to look like:

map2

Global Split now adding extra divisions for India, China, Russia etc

The challenge that comes, is that the regional routing which maybe resolved on the Internet side of things through Geo Routing such as the facilities provided by AWS Route53 and Oracle’s Dyn DNS as a result finding nearest local gateway. However Geo DNS may not be achievable internally (certainly not for AWS), as a result routing to the nearest local back-end needs to be handled by the gateway. Gateway based routing can solve the problem based on logical gateways – so if we logically group gateways regionally then that works. But, this then conflicts with the use of gateway based routing for separation of Development, Test etc.

Routing Options

So, what are the options? Here are a few …

  • Make you Logical divisions both by environment and by region – this is fine if you’re processing very high volumes i.e. hundreds of millions or more so the cost of additional Logical gateways is relatively small it the total budget.

map3

Taking the geo split and applying the traditional layers as well has increased the number of Logical gateways

This problem can be further exacerbated, if you consider many larger organisations are likely to end up with different cloud vendors in the same part of the world for example AWS and Azure, or Oracle and Google. So continuing the segmentation can become an expensive challenge as the following view helps show:

map4

It is possible contract things slightly by only have development and test cloud services where ever your core development center is based. Note that in the previous and next diagrams we’ve removed the region/country specific gateway drivers.

map5

  • Don’t segment based on environment, but only on region – but then how do you control changes in the API configuration so they don’t propagate immediately into production?
  • Keep the existing model but clone APIs for each region – certainly the tooling we’ve shared (Managing API Policy Versioning in Oracle API Platform) makes this possible, but it’s pretty inelegant and error prone as it be easy to forget to clone a change, and the cloning logic needs to be extended to take into account the bits that must be region specific.
  • Assuming you have a DNS address for the target, you could effectively rewrite the resolution of the address by changing its meaning in each gateway node’s host file. Inelegant, but effective if you have automated deployment and configuration of your gateway servers.
  • Header based routing with the region and environment as header attributes. This does require either the client to set the values (not good as you’re revealing to your API consumer traits of the implementation), or you apply custom policies before the header based routing that insert those attributes based on the gateway’s location etc.
  • Build a new type of gateway based routing which allows both the environment (dev, test etc) and location (region) to inform the routing,

Or, and the point of this blog, use gateway based routing and leverage some intelligent DNS naming and how the API Platform works with a little bit of Groovy or a custom Java policy.

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ODC Appreciation Day : ODC Podcasts

11 Thursday Oct 2018

Posted by in General, Oracle

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So I’m probably up bending the spirit of the ODC Appreciation Day, as the focus should be on tech. But this year I’d like to flag the podcasts put together by Bob Rhubart. These are as at-least diverse in subject as the Oracle technology portfolio. One month the podcast will be about API and the next AI, from Women in Technology to NoOps. Even if the subject is not an area that maybe of interest to you technically, the podcasts are still worth a listen you’ll encounter at-least one nugget of interesting information.

I have been fortunate enough to participate in the recording of a couple of podcasts. That combined with having In a previous roles been involved in recording and editing audio and video together means I can appreciate the effort that goes into producing the podcast. From gathering a group of different people together, often from around the world into a call isn’t always easy. Then editing the conversation to smooth out the introductions, pauses that can occur as all those non verbal cues are lost, shed any background noise to give a cohesive podcast takes time and practise.

Bob and Javed might make it look easy when recording Periscope videos at Open World and other events, but that comes from being able to control the environment – something you can’t do when participants are so far apart.

Analytics and Stats for APIs

05 Friday Oct 2018

Posted by in API Platform CS, General, Oracle, Technology

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NOTE:This utility needs revamping to support IDCS for more see Making Scripts Work with IDCS Deployed PaaS

The Oracle API Platform provides the means to examine statistics and slice and dice the numbers by application, gateway, duration and so on resulting in visually appealing graphical representations.  The way the analytics works means you can book mark specific views, so you can return the same report view with the relevant features as often as you like.  However, presently there is no data export option.

The question why would I want to export the information comes down to several possible use cases, all of which relate to cost management.  The API Platform will eventually have all the desired data views, but now something to help address the following:

  • money-tization, we can see which consumer has been using the services by how much and then send the data to a companies accounting systems to invoice the users
  • Ability to examine demand and workload over time to create a projection of the likely infrastructure – to achieve this the API statistics need to be overlaid with infrastructure and performance details so we can extrapolate API growth against server workload.

To address these kinds of requirements, we have taken advantage of the fact the API Platform has drunk its own Champagne as they say and made many of the analytics querying APIs publicly available.  As with the other API Platform tools, the logic has been written in Groovy, and freely available for use – we’ve covered the code through a Create Common license.

Tool includes a range of parameters to allow the data retrieved into a CSV file having filtered in a number of different ways – which logical gateways to examine, which API or Application(s) to report on.  Finally, just to help some basic stats are produced with a count of logical gateways, API calls, APIs defined and Application definitions. The first three factors inform your cloud costs. Together the stats can help Oracle understand your use case. Note that the parameters which impact the CSV generation can also materially impact the reporting numbers.

Parameters:

The 1st three values must always be provided and in the order shown here

  1. user name to access the source management cloud
  2. password for the source management cloud
  3. The server address without any attributes e.g. https://1.2.3.4

All the following values are optional

  • -h or -help – provides this information
  • -g – Logical gateway to retrieve numbers from e.g. production or development. using ALL with this parameter will result in ALL gateways being examined
  • -f – the file to target the CSV data should be written to. If not set then the default of
  • -t – indicates whether the data provided should be taken from an APPS perspective or from an API view by passing either APPS | API
  • -d – will get script to report more information about what is happening
  • -p – reporting period which is defined by a number as follows:
    • 0 – Last 365 days – data is given as per month
    • 1 – Last 30 days – this is the default if no information is provided – data is given as per day
    • 2 – Last 7 days – data is given as per day
    • 3 – Last day – data is given as per hour

NB – still testing the utility at this moment – will remove this comment once happy

Oracle Developer Meetup London – September 2018

18 Tuesday Sep 2018

Posted by in APIs & microservices, Dev Meetup, General, Technology

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#OracleDevMeetup in London - GraphQL

Last night we ran the latest of the Oracle Developer Meetups in London. This time Luis Weir presented on GraphQL, which got an very engaged discussion about the strengths and weaknesses of GraphQL, in-depth points about how the error paths should be handled among many other things.

The presentation material Luis used is based upon his Devoxx session earlier this year and can be seen here:

The links to Luis’ examples can be found on his GitHub account – https://github.com/luisw19/graphql-samples

After a insightful and thought provoking presentation on GraphQL the Drones with APIs project had its latest update.  Providing a lot of laughter to the evening’s proceedings. Including demonstration of flying the drone using REST APIs published via a gateway and Go back-end.  This included the DroneDash presenting a visual presentation of the commands being issues via REST, as seen here:

All the code, API definitions and documentation for people to add or extend can be found in the meetup’s GITHub – https://github.com/oracledeveloperslondon/.

A few of the useful links used or mentioned last night are:

 

The next meetup is planned for Monday November 19th.  Topics  will be published soon.

 

#OracleDevMeetup in London - GraphQL

Oracle Developer Podcast – Developer Evolution

19 Sunday Aug 2018

Posted by in development, General, Oracle, Technology

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podcast-356-dev-evolutionLast month I was fortunate enough to have been invited to participate in another Oracle Developer Podcast.  Rather than focusing on specific technologies, this focused on more how the thew job market is changing for IT and what might be driving change, and how things may change in the future. Check it out here.

As ever thanks to Bob Rhubart of the invitation, and putting together these excellent recordings.