Frequently Asked Questions

Sections in this FAQ include:
  • General CPL questions
  • Trouble shooting
  • EsoRex

General CPL questions

Q: What does the acronym CPL stand for?
A: Common Pipeline Library

Q: When was the CPL made publicly available?
A: Version 1.0 of the CPL was made available on 17 December, 2003. Version 2.0 was released on 8 April, 2005.

Q: Where can I find additional information about the CPL?
A: Please consult the CPL Documentation web page. If you cannot find what you are looking for, please get in touch with the CPL team via the appropriate address / contact-point, as listed on the CPL Contact web page.

Q: Are there any tools that I can use to run my pipeline recipes?
A: Yes. While technically anyone can write their own application to run recipes, ESO provides two: EsoRex and GASGANO.

Trouble shooting

Q: I get an error message along the lines of "Undefined symbol: get_datetime_iso8601()", which prevents compilation.
A: This is because you are using a more recent version of QFITS than that which your version of CPL requires. CPL 1.0.x requires qfits 4.3.5 (availlable from the qfits web page).

Note, however, that developers are advised to upgrade to the latest version of CPL.

EsoRex

Q: When was EsoRex made publicly available?
A: EsoRex was made available on 1 July, 2004.

Q: Where can I find information about EsoRex.
A: Take a look at the EsoRex website. See also the README file in the distribution.

Q: Recipes run with EsoRex work once, but then say that they can't generate any products. What is wrong?
A: (EsoRex v1.x) When a recipe is used with the --suppress-prefix option, and the --output-dir is set to the current working directory, then the first execution of a recipe will work correctly, but subsequent executions may fail. This is due to output products being given "read-only" permission (to avoid the potential inadvertant loss of products). The recipe itself is unable to modify the permissions, and thus it fails when attempting to create the file. The solution (other than using a different output directory or prefixes) is to change the permission of these output files or delete them prior to any subsequent execution of that recipe.

(EsoRex v2+) This will only occur if the --output-readonly has been set (this option exists for use with the Paranal archiving system). As this is not the default behaviour, it is less likely to occur. However, if it is used in conjunction with the --suppress-prefix option, then the same effect as described above will occur.