doc: add basic docs about declarative projects

[?]

Oct 31, 2016, 5:17 PM

VDT6CUITZL2M3DSFHKAD7VYSW354AU4GDMJ7PWTFLTPUCFKTJSZAC

Dependencies

[2] LW755CJK doc: Write "Adding More Jobs".
[*] 6A6CZ7SC draft manual
[*] PKE6I67S doc: Import the "Creating Projects" chapter by Visser & Dolstra.

Change contents

file addition: declarative-projects.xml (----------)

[4.18]

<section xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xml:id="sec-declarative-projects">

<title>Declarative projects</title>
<para>
Hydra also supports declarative projects, where jobsets are generated
and configured automatically from specification files instead of being
managed through the UI. A jobset specification is a JSON object
containing the configuration of the jobset, for example:
</para>
<programlisting language="json">
{
"enabled": 1,
"hidden": false,
"description": "js",
"nixexprinput": "src",
"nixexprpath": "release.nix",
"checkinterval": 300,
"schedulingshares": 100,
"enableemail": false,
"emailoverride": "",
"keepnr": 3,
"inputs": {
"src": { "type": "git", "value": "git://github.com/shlevy/declarative-hydra-example.git", "emailresponsible": false },
"nixpkgs": { "type": "git", "value": "git://github.com/NixOS/nixpkgs.git release-16.03", "emailresponsible": false }
}
}
</programlisting>
<para>
To configure a declarative project, take the following steps:
</para>
<orderedlist numeration="arabic" spacing="compact">
<listitem>
<para>
Create a jobset repository in the normal way (e.g. a git repo with
a <literal>release.nix</literal> file, any other needed helper
files, and taking any kind of hydra input), but without adding it
to the UI. The nix expression of this repository should contain a
single job, named <literal>jobsets</literal>. The output of the
<literal>jobsets</literal> job should be a JSON file containing an
object of jobset specifications. Each member of the object will
become a jobset of the project, configured by the corresponding
jobset specification.
</para>
</listitem>
<listitem>
<para>
In some hydra-fetchable source (potentially, but not necessarily,
the same repo you created in step 1), create a JSON file
containing a jobset specification that points to the jobset
repository you created in the first step, specifying any needed
inputs (e.g. nixpkgs) as necessary.
</para>
</listitem>
<listitem>
<para>
In the project creation/edit page, set declarative input type,
declarative input value, and declarative spec file to point to the
source and JSON file you created in step 2.
</para>
</listitem>
</orderedlist>
<para>
Hydra will create a special jobset named <literal>.jobsets</literal>,
which whenever evaluated will go through the steps above in reverse
order:
</para>
<orderedlist numeration="arabic" spacing="compact">
<listitem>
<para>
Hydra will fetch the input specified by the declarative input type
and value.
</para>
</listitem>
<listitem>
<para>
Hydra will use the configuration given in the declarative spec
file as the jobset configuration for this evaluation. In addition
to any inputs specified in the spec file, hydra will also pass the
<literal>declInput</literal> argument corresponding to the input
fetched in step 1.
</para>
</listitem>
<listitem>
<para>
As normal, hydra will build the jobs specified in the jobset
repository, which in this case is the single
<literal>jobsets</literal> job. When that job completes, hydra
will read the created jobset specifications and create
corresponding jobsets in the project, disabling any jobsets that
used to exist but are not present in the current spec.
</para>
</listitem>
</orderedlist>
</section>
edit in doc/manual/projects.xml at line 3

[5.214]

[5.214]

xmlns:xi="http://www.w3.org/2001/XInclude"
edit in doc/manual/projects.xml at line 472

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[2.3342]

<xi:include href="declarative-projects.xml" />