Dns-exporter

-------------------------

Changed
~~~~~~~

- Remove wrong buckets on response time Histogram, replace with default
buckets

-------------------------

Fixed
~~~~~

- Catch ``httpx.ConnectTimeout`` from protocol ``doh`` as failure
reason ``timeout``

Changed
~~~~~~~

- Add more labels to the ``dnsexp_scrape_failures_total`` metric so it
has all the same labels as ``dnsexp_dns_query_time_seconds`` in
addition to the ``reason`` label.

-------------------------

Fixed
~~~~~

- Always send Content-Length header for metrics responses
- Do not overwrite ``no_nsid`` placeholder if a blank NSID is received
from server (to avoid blank labels)

Changed
~~~~~~~

- Add the ``monitor`` label in all examples, also the ones scraping
internal metrics

-------------------------

Changed
~~~~~~~

- Minimum supported DNSPython version is now 2.5.0
- Log at level warning when encountering an unknown failure
- Remove failure reason ``connection_refused`` and report it as
``connection_error`` along with the rest of socket related errors.
- Remove ``dnsexp_failures_total`` from per-scrape metrics. Failure
reasons are now tracked only under ``/metrics``.
- Switch from ``http.server.HTTPServer`` to
``http.server.ThreadingHTTPServer``
- Add new failure reason ``invalid_response_statuscode`` for DoH
failures.
- The default for the ``collect_ttl_rr_value_length`` has been changed
from ``255`` to ``50`` to reduce label cardinality.
- Docs: Mention the importance of scraping internal metrics under
``/metrics``
- Docs: Mention adding a ``monitor`` label to identify the exporter in
use, for setups where multiple instances of ``dns_exporter`` is
running.
- Update unit tests for all of the above


Fixed
~~~~~

- Always send content-length header for static responses (100, thanks
jcodybaker!)

---------------------------

Added
~~~~~

- Unit tests for proxy code
- Unit tests for new code introduced to make ruff happy
- New ``collect_ttl`` setting to control collection of per-RR TTL
metrics. Default is true.
- New ``verify_certificate`` bool setting to control validation of
certificates on encrypted protocols. Default is true.
- New ``verify_certificate_path`` str setting to override the system CA
when validating certificates on encrypted protocols. Leave empty to
use the default system CA. Default is an empty string.

Changed
~~~~~~~

- Replace black, flake8, isort, pydocstyle with ruff
- Some refactoring to reduce complexity and ease testing
- Much linting
- Move coverage.py config to .coveragerc to make showing measurement
contexts in coverage html work
- Proxy support for DoQ disabled, pending next dnspython release with
https://github.com/rthalley/dnspython/pull/1060
- Improve unit tests
- Polish dockerhub action a bit (thanks dallemon!)
- Re-add custom histogram buckets for metric
``dnsexp_dns_responsetime_sedonds`` from 1 second doubling until
4194304 seconds (48 days).
- Build docs in ``pre-commit`` to avoid breaking them
- Include ``protocol``, ``server``, and ``proxy`` labels in the
``dnsexp_scrape_failures_total`` Counter metric.

Fixed
~~~~~

- Fixed a bug which made ``fail_if_all_match_regexp`` validation
succeed on the first matching RR (not considering further RRs).

---------------------------

Changed
~~~~~~~

- Updated some dev and test dependencies
- Improve debug logging
- Enable proxy support for all protocols except DoT