Robots.txt file is cached by Full Page Cache of Magento

[dandrikop]

Preconditions and environment

When you change the contents of the robots.txt file via Content > Design > Configuration > Search Engine Robots, the changes do not become immediately available on the front-end of the Magento website even if you refresh the Configuration cache via System > Cache Management. It seems that the page https://www.example.com/robots.txt is cached by the Full Page Cache of Magento. I tested that on Magemto 2.4.6-p7 by using REDIS as the Full Page Cache of Magento.

Steps to reproduce

1. Visit the robots.txt file via the link: https://www.example.com/robots.txt
2. Change the content of the robots.txt file via Content > Design > Configuration > Search Engine Robots
3. Refresh the Configuration cache via System > Cache Management
4. Visit again the robots.txt file via the link: https://www.example.com/robots.txt

Expected result

The new content of the robots.txt file should be viewed at https://www.example.com/robots.txt

Actual result

The old content of the robots.txt file is viewed at "https://www.example.com/robots.txt".

Additional information

The only way to make the changes of the robots.txt available at the front-end of the Magento website is by flushing the Full Page Cache. However, this work-around is not appropriate for the following reasons:

1. Robots.txt is considered configuration, and so any configuration change should become available immediately.
2. The Full Page Cache significantly improves the performance of the Magento front-end.
3. The Full Page Cache may need several days to be filled again even by using intensive Cache warmers.

So, it's worth flushing the Full Page Cache only when there are applied changes affecting a large number of pages, such as the installation of a new module, or the update of existing module.

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[m2-assistant]

Hi @engcom-Bravo. Thank you for working on this issue.
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[engcom-Bravo]

Hi @dandrikop,

Thanks for your reporting and collaboration.

We have verified the issue in Latest 2.4-develop instance and the issue is not reproducible.Kindly refer the screenshots.

The new content of the robots.txt file viewed at https://www.example.com/robots.txt

Kindly recheck the issue in Latest 2.4-develop instance and elaborate the steps to reproduce and please let us know if we are missing anything.

Thanks.

[dandrikop]

Hello @engcom-Bravo,

I have a multi-store implementation of Magento 2.4.6-p7 with 7 websites, each website has one store, and each store has one store view. The routing at the appropriate store view is regulated by the .htaccess file with directives such as the following ones:

SetEnvIf Host fr.dlastore.com MAGE_RUN_CODE=french_dla
SetEnvIf Host fr.dlastore.com MAGE_RUN_TYPE=store

I'm using REDIS for Magento FPC.

The contents of the “robots.txt” file per store view are stored at the database table “core_config_data” at the path “design/search_engine_robots/custom_instructions”. So, no physical files “robots.txt” are created.

I can easily reproduce the problem following the steps below:

1. Visit the “robots.txt” file for a specific store view via browser, e.g.: https://fr.example.com/robots.txt
2. Change the contents of the robots.txt file for the specific store view via Content > Design > Configuration > Search Engine Robots
3. Refresh the Configuration cache via System > Cache Management
4. Visit again the robots.txt file for the specific store view, e.g.: https://fr.example.com/robots.txt

At the front-end the contents of the "robots.txt" remain the same. Upon requesting the page, I could see the relevant HGET line at REDIS by using the MONITOR command as follows:

$ redis-cli -p 6971 monitor | grep "3 127.0.0.1:" | grep FRENCH

So, I verified that the HTTP request on the browser for the "robots.txt" was routed to RPC (REDIS).

[engcom-Bravo]

Hi @dandrikop,

Thanks for your update.

We have tried to reproduce the issue in Latest 2.4-develop Magento instance and we are not able to reproduce the issue.Kindly refer the screenshots.

We have 7 websites, each website has one store, and each store has one store view

We have configured REDIS for Magento FPC

The new content of the robots.txt file viewed at https://www.example.com/robots.txt

Kindly recheck the issue in Latest 2.4-develop instance and elaborate the steps to reproduce and please let us know if we are missing anything.

Thanks.

[dandrikop]

Hello @engcom-Bravo,

Just a question: what is the exact version of 2.4-develop Magento instance you're using for the specific test? Is it 2.4.7?

[engcom-Hotel]

Hello @dandrikop,

Actually, it is a development branch that is ahead of 2.4.7.

Thanks