Accepted Solutions
@oblanco -
In the exam, you will assume that the information is displaying correctly and you will move on to the next question but in reality, when the grade script run, it will be marked as FAIL even if the information was displayed correctly on the screen. this is scary.
That would be a very incorrect assumption. The question clearly states that the web application gets data from a containerized database. The CURL command you are running just verifies that the webserver is working and responding. It does not return any data from a database. In a real-world scenario if you had a web application getting data from a database, you would check that the web application is up and that the database is up and responding (providing the data to the web application). Another clue here, is that you are told there is a web application using a containerized database.
There are multiple curl commands used to check and verify, but sometimes that confuses people, so I will show Firefox with the site ...
The first CURL command shows that the HTTPD (Apache webserver) is online and proving the PHP page, but notice, there is no data being returned from a database. You only have the headers that are builtin as part of the PHP file.
So I will concede that currently, there is something wrong with the PHP website as even with the database able to connect, it doesn't display and return the data. However, when looking at things it is clear that no data is coming from the container (database) and it is impossible for something external to connect to a database without the port being available.
The other part that is thrown in here as a curveball is troubleshooting the web application itself. Because even once the port has been exposed, things aren't working. The reason is that the webapp was looking at an incorrect IP address for the container. You need to also update the PHP file on the webapp.
Once the Webserver is up and running and the PHP application has been modified with the container port forwarding traffic to port 3306, the application can get the data that is needed. The database conainter is supposed to be providing data to other services, so a quick podman ps showing that the application doesn't have exposed ports lets you know that external applications cannot access data within the database. If the webserver would have been on ServerB (for example), there would have been no way for data to leave (granted at this point you would also need to play with firewalls and such o make it work).
Again, the solutions and steps are for one way. As for the grading script, it should fail right off on the first item because fixing HTTPD and Apache has nothing to do with the containerized application.
So not only does the script check that the database container is up, running, and accessible, it also then goes and looks to ensure the data is coming back. Being extremely OCD on checking things and in cases of a REAL WORLD scenario or the EXAM, I would take things a step further and login to the MySQL database and verify what is there. We are given information through troubleshooting on what should be coming out so you could do a connection to the database and do a "select * from <table_name>" to see the data that is returned and verify it matches the listing from the PHP website.
By completing this process, you are showing that the data is coming out of the database container and the PHP website matches the contents that are in the Database.
Finally, one thing to keep in mind, the classroom environment, labs, and sometimes the GEs can have some slight issues with checks and verifications in terms of gradining and implementation as the classes are quite large and lots of things can happen. The team writing the exams and creating the evaluations and problems for the exams are a completely different team and way way way more care has been put into the development and testing of the exams and evaluation process. The courses having Guided Exercises and then End of Chapter labs with the solutions, sometimes the grading on the EoC labs can be less robust in catching all the different aspects and may "accidentally" look for something that was done in a solution. This is "not" the way exams are designed.
Again, the larger concern here is that just checking an HTTP website isn't sufficient in this case and the solution provided guides you through steps. However, to fully understand, you should be able to work this without a solution and realize the steps to take to troubleshoot a scenario like this, because you are right, if there is an assumption the when a website returns data things are good and everything is OK, that is very scary indeed as you should know if what is being returned is correct and valid. The only way to do that in this case would be to connect to the database and view the data and when attempting to connect with a client, you would immediately know that MySQL client couldn't connect to the database.
@oblanco -
In the exam, you will assume that the information is displaying correctly and you will move on to the next question but in reality, when the grade script run, it will be marked as FAIL even if the information was displayed correctly on the screen. this is scary.
That would be a very incorrect assumption. The question clearly states that the web application gets data from a containerized database. The CURL command you are running just verifies that the webserver is working and responding. It does not return any data from a database. In a real-world scenario if you had a web application getting data from a database, you would check that the web application is up and that the database is up and responding (providing the data to the web application). Another clue here, is that you are told there is a web application using a containerized database.
There are multiple curl commands used to check and verify, but sometimes that confuses people, so I will show Firefox with the site ...
The first CURL command shows that the HTTPD (Apache webserver) is online and proving the PHP page, but notice, there is no data being returned from a database. You only have the headers that are builtin as part of the PHP file.
So I will concede that currently, there is something wrong with the PHP website as even with the database able to connect, it doesn't display and return the data. However, when looking at things it is clear that no data is coming from the container (database) and it is impossible for something external to connect to a database without the port being available.
The other part that is thrown in here as a curveball is troubleshooting the web application itself. Because even once the port has been exposed, things aren't working. The reason is that the webapp was looking at an incorrect IP address for the container. You need to also update the PHP file on the webapp.
Once the Webserver is up and running and the PHP application has been modified with the container port forwarding traffic to port 3306, the application can get the data that is needed. The database conainter is supposed to be providing data to other services, so a quick podman ps showing that the application doesn't have exposed ports lets you know that external applications cannot access data within the database. If the webserver would have been on ServerB (for example), there would have been no way for data to leave (granted at this point you would also need to play with firewalls and such o make it work).
Again, the solutions and steps are for one way. As for the grading script, it should fail right off on the first item because fixing HTTPD and Apache has nothing to do with the containerized application.
So not only does the script check that the database container is up, running, and accessible, it also then goes and looks to ensure the data is coming back. Being extremely OCD on checking things and in cases of a REAL WORLD scenario or the EXAM, I would take things a step further and login to the MySQL database and verify what is there. We are given information through troubleshooting on what should be coming out so you could do a connection to the database and do a "select * from <table_name>" to see the data that is returned and verify it matches the listing from the PHP website.
By completing this process, you are showing that the data is coming out of the database container and the PHP website matches the contents that are in the Database.
Finally, one thing to keep in mind, the classroom environment, labs, and sometimes the GEs can have some slight issues with checks and verifications in terms of gradining and implementation as the classes are quite large and lots of things can happen. The team writing the exams and creating the evaluations and problems for the exams are a completely different team and way way way more care has been put into the development and testing of the exams and evaluation process. The courses having Guided Exercises and then End of Chapter labs with the solutions, sometimes the grading on the EoC labs can be less robust in catching all the different aspects and may "accidentally" look for something that was done in a solution. This is "not" the way exams are designed.
Again, the larger concern here is that just checking an HTTP website isn't sufficient in this case and the solution provided guides you through steps. However, to fully understand, you should be able to work this without a solution and realize the steps to take to troubleshoot a scenario like this, because you are right, if there is an assumption the when a website returns data things are good and everything is OK, that is very scary indeed as you should know if what is being returned is correct and valid. The only way to do that in this case would be to connect to the database and view the data and when attempting to connect with a client, you would immediately know that MySQL client couldn't connect to the database.
