wip: dependency-tracked build triggering

buildbot_nix/__init__.py

@@ -56,11 +56,13 @@ class BuildTrigger(Trigger):
         self,
         builds_scheduler: str,
         jobs: list[dict[str, Any]],
+        drv_info: dict[str, Any],
         **kwargs: Any,
     ) -> None:
         if "name" not in kwargs:
             kwargs["name"] = "trigger"
         self.jobs = jobs
+        self.drv_info = drv_info
         self.config = None
         self.builds_scheduler = builds_scheduler
         Trigger.__init__(
@@ -82,6 +84,20 @@ class BuildTrigger(Trigger):
         build_props = self.build.getProperties()
         source = f"nix-eval-lix"
 
+        all_deps = dict()
+        for drv, info in self.drv_info.items():
+            all_deps[drv] = set(info.get("inputDrvs").keys())
+        def closure_of(key, deps):
+            r, size = set([key]), 0
+            while len(r) != size:
+                size = len(r)
+                r.update(*[ deps[k] for k in r ])
+            return r.difference([key])
+        job_set = set(( drv for drv in ( job.get("drvPath") for job in self.jobs ) if drv ))
+        all_deps = { k: list(closure_of(k, all_deps).intersection(job_set)) for k in job_set }
+
+        build_props.setProperty("sched_state", all_deps, source, True)
+
         triggered_schedulers = []
         for job in self.jobs:
             attr = job.get("attr", "eval-error")
@@ -168,12 +184,31 @@ class NixEvalCommand(buildstep.ShellMixin, steps.BuildStep):
                 if not system or system in self.supported_systems:  # report eval errors
                     filtered_jobs.append(job)
 
+            drv_show_log: Log = yield self.getLog("stdio")
+            drv_show_log.addStdout(f"getting derivation infos\n")
+            cmd = yield self.makeRemoteShellCommand(
+                stdioLogName=None,
+                collectStdout=True,
+                command=(
+                    ["nix", "derivation", "show", "--recursive"]
+                    + [ drv for drv in (job.get("drvPath") for job in filtered_jobs) if drv ]
+                ),
+            )
+            yield self.runCommand(cmd)
+            drv_show_log.addStdout(f"done\n")
+            try:
+                drv_info = json.loads(cmd.stdout)
+            except json.JSONDecodeError as e:
+                msg = f"Failed to parse `nix derivation show` output for {cmd.command}"
+                raise BuildbotNixError(msg) from e
+
             self.build.addStepsAfterCurrentStep(
                 [
                     BuildTrigger(
                         builds_scheduler=f"lix-nix-build",
                         name="build flake",
                         jobs=filtered_jobs,
+                        drv_info=drv_info,
                     ),
                 ],
             )