Add installer.subcommand field to user agent

[zsol]

This PR extends the installer.subcommand field of the user agent struct, and then logs its value by serializing it using shlex.join() as explained in #233.

Test plan

The functional tests in test_functions.py were changed to expect a subcommand field to be logged, and now the coverage includes:

• no subcommand field
• subcommand field with a single value
• subcommand field with multiple values
• subcommand field with multiple values, one of them containing spaces (to be escaped by the implementation)

Changes to the downloads fixture

--- downloads-before	2025-11-24 12:09:45
+++ downloads-after	2025-11-24 12:09:34
@@ -1,4 +1,5 @@
 download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/f7/12/ec3f2e203afa394a149911729357aa48affc59c20e2c1c8297a60f33f133/threadpoolctl-2.1.0-py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|threadpoolctl|2.1.0|bdist_wheel|pip/20.1.1 {"ci":null,"cpu":"x86_64","distro":{"id":"stretch","libc":{"lib":"glibc","version":"2.24"},"name":"Debian GNU/Linux","version":"9"},"implementation":{"name":"CPython","version":"3.7.9"},"installer":{"name":"pip","version":"20.1.1"},"openssl_version":"OpenSSL 1.1.0l  10 Sep 2019","python":"3.7.9","setuptools_version":"47.1.0","system":{"name":"Linux","release":"4.15.0-112-generic"}}
-download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/cd/f9/8fad70a3bd011a6be7c5c6067278f006a25341eb39d901fbda307e26804c/django_crum-0.7.9-py2.py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|django-crum|0.7.9|bdist_wheel|pip/20.0.2 {"ci":null,"cpu":"x86_64","distro":{"id":"xenial","libc":{"lib":"glibc","version":"2.23"},"name":"Ubuntu","version":"16.04"},"implementation":{"name":"CPython","version":"3.8.5"},"installer":{"name":"pip","version":"20.0.2"},"openssl_version":"OpenSSL 1.0.2g  1 Mar 2016","python":"3.8.5","setuptools_version":"44.1.0","system":{"name":"Linux","release":"4.4.0-1113-aws"}}
+download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/cd/f9/8fad70a3bd011a6be7c5c6067278f006a25341eb39d901fbda307e26804c/django_crum-0.7.9-py2.py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|django-crum|0.7.9|bdist_wheel|pip/20.0.2 {"ci":null,"cpu":"x86_64","distro":{"id":"xenial","libc":{"lib":"glibc","version":"2.23"},"name":"Ubuntu","version":"16.04"},"implementation":{"name":"CPython","version":"3.8.5"},"installer":{"name":"pip","version":"20.0.2","subcommand":[]},"openssl_version":"OpenSSL 1.0.2g  1 Mar 2016","python":"3.8.5","setuptools_version":"44.1.0","system":{"name":"Linux","release":"4.4.0-1113-aws"}}
 download|Thu, 07 Jan 2021 20:54:56 GMT|US|/packages/c5/db/e56e6b4bbac7c4a06de1c50de6fe1ef3810018ae11732a50f15f62c7d050/enum34-1.1.6-py2-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|enum34|1.1.6|bdist_wheel|(null)
-download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/cd/f9/8fad70a3bd011a6be7c5c6067278f006a25341eb39d901fbda307e26804c/django_crum-0.7.9-py2.py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|django-crum|0.7.9|bdist_wheel|pip/22.0.3 {"ci":true,"cpu":"arm64","distro":{"name":"macOS","version":"12.3"},"implementation":{"name":"CPython","version":"3.9.10"},"installer":{"name":"pip","version":"22.0.3"},"openssl_version":"OpenSSL 1.1.1m  14 Dec 2021","python":"3.9.10","rustc_version":"1.59.0","setuptools_version":"60.9.0","system":{"name":"Darwin","release":"21.4.0"}}
+download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/cd/f9/8fad70a3bd011a6be7c5c6067278f006a25341eb39d901fbda307e26804c/django_crum-0.7.9-py2.py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|django-crum|0.7.9|bdist_wheel|pip/22.0.3 {"ci":true,"cpu":"arm64","distro":{"name":"macOS","version":"12.3"},"implementation":{"name":"CPython","version":"3.9.10"},"installer":{"name":"pip","version":"22.0.3","subcommand":["install","something with a space"]},"openssl_version":"OpenSSL 1.1.1m  14 Dec 2021","python":"3.9.10","rustc_version":"1.59.0","setuptools_version":"60.9.0","system":{"name":"Darwin","release":"21.4.0"}}
+download|Thu, 07 Jan 2021 20:54:54 GMT|US|/packages/cd/f9/8fad70a3bd011a6be7c5c6067278f006a25341eb39d901fbda307e26804c/django_crum-0.7.9-py2.py3-none-any.whl|TLSv1.2|ECDHE-RSA-AES128-GCM-SHA256|django-crum|0.7.9|bdist_wheel|pip/22.0.3 {"ci":true,"cpu":"arm64","distro":{"name":"macOS","version":"12.3"},"implementation":{"name":"CPython","version":"3.9.10"},"installer":{"name":"uv","version":"0.9.11","subcommand":["pip","install"]},"openssl_version":"OpenSSL 1.1.1m  14 Dec 2021","python":"3.9.10","rustc_version":"1.59.0","setuptools_version":"60.9.0","system":{"name":"Darwin","release":"21.4.0"}}

[di]

LGTM, we will need to wait for the schema migration though.

[zsol]

Will ingestion fail for unknown fields?

[di]

Looks like no, actually:

linehaul-cloud-function/main.py

Line 190 in df76e20

job_config.ignore_unknown_values = True