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Docker automatically stopped

Docker automatically stopped

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This morning I found that the Docker service on one our linux servers for no apparent reason had stopped. From the entries in syslog I could see that Docker had been going up and down since about 06:34 in the morning. Extract from syslog: I came across https://www.claudiokuenzler.com/blog/689/rancher-error-response-from-daemon-dockerd-deleted-no-such-file-or-directory, and from the comment section there I was led to check what the unattended upgrades had been doing this morning, and found this: On this particular linux server we don’t really wish…

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openpyxl’s “load_workbook” return empty list of sheets

openpyxl’s “load_workbook” return empty list of sheets

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Consider this code: When using one of my xlsx-files as input, my code produced the output Sheet names: [] followed by this expection: After some investigating, I found that the file had been saved as “Strict Open XML Spreadsheet (xlsx)” instead of “Excel Workbook (xslx)”. Both files for some reason have the same file extension, but the former was not supported by the openpyxl library. Saving the file as “Excel Workbok (xslx)” got the code working again.

Adding “–version” parameter to “python3 setup.py”

Adding “–version” parameter to “python3 setup.py”

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When building Python packages using setuptools, you typically manually set the upcoming package version in setup.py. For my use case, I found it better to provide the version number on the command line such as this: setuptools isn’t very fond of command line parameters, so I made a quick-n-dirty hack to work around this limitation:

SQLAlchemy + Database Link => ORA-04054

SQLAlchemy + Database Link => ORA-04054

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I’ve got this SQLAclhemy table definition that describes a table I’ll be accessing over an Oracle database link: I first created a database link such as this: In SQLAlchemy, access a table column (in a query) via that link would look like tihs I turns out that SQLAlchemy with Oracle database links isn’t a very good match, and easily results in errors such as this: To work around this issue, I created a synonym like this: Now, accessing the table…

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Using the factory pattern to create different emails based on input parameters

Using the factory pattern to create different emails based on input parameters

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I wrote a small service that takes an MQ message as input, and based on the contents of the message creates and sends an email. The different types of incoming MQ messages require different types of emails to be created, so I needed a maintainable way to create different emails. For my use case, I found that the factory pattern was a good fit. Consider this code: My business logic code that uses this code then get to be as…

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Spying on Python functions

Spying on Python functions

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I was writing test code for a Python project, and needed to spy on the functions of one of the main object’s, called “server”, object instances called “rest_client”. By simply replacing the “rest_client” instance with a mock that passes the actual call to the wrapped object, I’m able to execute the production code of “rest_client” while later on making assertions.