This is necessary because the required system type can become
available later (e.g. by being provisioned by the
auto-scaler). However, in the future, we may want to fail steps if
they have been unsupported for more than a certain amount of time.
For example, steps that require the "kvm" feature may require a
different kind of machine to be provisioned. This can also be used to
require performance-sensitive tests to run on a particular kind of
machine, e.g., by setting requiredSystemFeatures to something like
"ec2-i2.8xlarge".
"hydra-queue-runner --status" now prints how many runnable and running
build steps exist for each machine type. This allows additional
machines to be provisioned based on the Hydra load.
If there is no input named 'inputs', hydra-eval-jobs now passes in a set
of lists, where each attribute corresponds to an input defined in the
jobset specification and each list element is a different input alt, as
an argument named 'inputs'.
Among other things, this allows for generic hydra expressions to be
shared amongst projects with similar structures but different sets of
specific inputs.
Builds can now emit metrics that Hydra will store in its database and
render as time series via flot charts. Typical applications are to
keep track of performance indicators, coverage percentages, artifact
sizes, and so on.
For example, a coverage build can emit the coverage percentage as
follows:
echo "lineCoverage $pct %" > $out/nix-support/hydra-metrics
Graphs of all metrics for a job can be seen at
http://.../job/<project>/<jobset>/<job>#tabs-charts
Specific metrics are also visible at
http://.../job/<project>/<jobset>/<job>/metric/<metric>
The latter URL also allows getting the data in JSON format (e.g. via
"curl -H 'Accept: application/json'").
If Hydra isn't hosted on https://example.com/ but something like
https://example.com/hydra/, the URL for /api/scmdiff would have ended up
on /api/scmdiff rather than /hydra/api/scmdiff.
This is because we didn't use the URI resolver from the controller,
hence we're using it now to build up the whole URL including the query
string.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
