Skip to main content

Startup your ORDS container after your Oracle DB container is ready

If you are using multiple containers to set up your Oracle Development (or Test or Production) environment - as I described here - you probably ran into the issue that your ORDS container was started before the Database was started up. This results in an ORDS container that is not working - at least not as you need to.

Using Docker Compose you can specify a depends_on option, for instance in the ORDS container configuration you specify (where "oracle" refers to the container that holds the Oracle database) :
depends_on : - oracle
but this only means the ORDS container will start after the "oracle" container has been started. That does not mean the Oracle database inside the container is started and available!

So how do we tell the ORDS to configure itself in one container to wait for the database in another container is ready to use?
Step 1:
Start the Oracle database (container), connect to it and enable a port - in this example 8080 - in the Oracle database 

begin 
 dbms_xdb_config.sethttpport( 8080 ); 
end;
/

This port will become available when the database is up and running.

Step 2:
Get the "wait-for-it" shell script from https://github.com/vishnubob/wait-for-it. In your ORDS Dockerfile copy this in the root of your container and change the Entrypoint from just /config_ords_and_run_catalina.sh to a call to /wait-for-it.sh specifying the Oracle port from step 1. You don't need to use port forwarding as both containers run on the same Docker network and can access each others ports. The example below will wait for max 2 minutes for the Oracle database to start up (if it isn't ready, the rest of the script will not run as it won't make any sense).
COPY ./wait-for-it.sh / RUN chmod +x /*.sh ENTRYPOINT ["/wait-for-it.sh","oracle:8080","--timeout=120","-s","--","/config_ords_and_run_catalina.sh"]
After recreating the image with these changes to the Dockerfile and using Docker Compose to start it all up, the logging of the ORDS container will show the following before proceeding with the configuration:

wait-for-it.sh: waiting 120 seconds for oracle:8080
wait-for-it.sh: oracle:8080 is available after 42 seconds

And that is exactly what we want! Now we defined a proper dependency between our database to be available and our ORDS service.

Note: This will only work properly if your database is already created. If you want this to work when the database has to be created first, you need to add step 1 into your database creation script and need to set the timeout parameter in step 3 to a higher value.

Comments

Popular posts from this blog

apex_application.g_f0x array processing in Oracle 12

If you created your own "updatable reports" or your custom version of tabular forms in Oracle Application Express, you'll end up with a query that looks similar to this one:
then you disable the "Escape special characters" property and the result is an updatable multirecord form.
That was easy, right? But now we need to process the changes in the Ename column when the form is submitted, but only if the checkbox is checked. All the columns are submitted as separated arrays, named apex_application.g_f0x - where the "x" is the value of the "p_idx" parameter you specified in the apex_item calls. So we have apex_application.g_f01, g_f02 and g_f03. But then you discover APEX has the oddity that the "checkbox" array only contains values for the checked rows. Thus if you just check "Jones", the length of g_f02 is 1 and it contains only the empno of Jones - while the other two arrays will contain all (14) rows. So for processing y…

Adding items to your Interactive Grid Toolbar

The APEX Interactive Grid uses the Toolbar widget to create the default Toolbar showing the Search box, Actions menu, Save button etc. And since quite a while there is a nice Plugin "Extend IG Toolbar" by Marko Goricki that makes it very easy to add additional buttons to the Toolbar.

But what if you need more than a button? 
Inspecting the contents of widget.toolbar.js, you can easily spot there can be added more to the Toolbar than just a button: The type of control, available values:
"STATIC", "TEXT", "SELECT", "BUTTON", "MENU", "RADIO_GROUP", "TOGGLE".
The first example will show a way to easily switch from one filter to another. Of course we could use the standard functionality and create two different Report views, but using a Radio Group on the Toolbar gives a more "Tab" like user experience.

So how can we create a Radio Group that looks like a switch in the Toolbar?
In the Javascript Code …

Refresh selected row(s) in an Interactive Grid

In my previous post I blogged about pushing changed rows from the dabatase into an Interactive Grid. The use case I'll cover right here is probably more common - and therefore more useful!

Until we had the IG, we showed the data in a report (Interactive or Classic). Changes to the data where made by popping up a form page, making changes, saving and refreshing the report upon closing the dialog. Or by clicking an icon / button / link in your report that makes some changes to the data (like changing a status) and ... refresh the report.  That all works fine, but the downsides are: The whole dataset is returned from the server to the client - again and again. And if your pagination size is large, that does lead to more and more network traffic, more interpretation by the browser and more waiting time for the end user.The "current record" might be out of focus after the refresh, especially by larger pagination sizes, as the first rows will be shown. Or (even worse) while you…