asp: refactor low level API to permit the injection of configuration

This allows writing extension commands that can benchmark
different configurations in clingo, or try different
configurations for a single test.

lib/spack/docs/conf.py

@@ -200,6 +200,7 @@ def setup(sphinx):
     ("py:class", "_io.BufferedReader"),
     ("py:class", "unittest.case.TestCase"),
     ("py:class", "_frozen_importlib_external.SourceFileLoader"),
+    ("py:class", "clingo.Control"),
     # Spack classes that are private and we don't want to expose
     ("py:class", "spack.provider_index._IndexBase"),
     ("py:class", "spack.repo._PrependFileLoader"),

lib/spack/spack/cmd/solve.py

@@ -42,13 +42,6 @@ def setup_parser(subparser):
         "  solutions    models found by asp program\n"
         "  all          all of the above",
     )
-    subparser.add_argument(
-        "--models",
-        action="store",
-        type=int,
-        default=0,
-        help="number of solutions to search (default 0 for all)",
-    )
 
     # Below are arguments w.r.t. spec display (like spack spec)
     arguments.add_common_arguments(subparser, ["long", "very_long", "install_status"])
@@ -170,10 +163,6 @@ def solve(parser, args):
                 % (d, ", ".join(show_options + ("all",)))
             )
 
-    models = args.models
-    if models < 0:
-        tty.die("model count must be non-negative: %d")
-
     # Format required for the output (JSON, YAML or None)
     required_format = args.format
 
@@ -195,7 +184,6 @@ def solve(parser, args):
         result = solver.solve(
             specs,
             out=output,
-            models=models,
             timers=args.timers,
             stats=args.stats,
             setup_only=setup_only,
@@ -204,9 +192,7 @@ def solve(parser, args):
             _process_result(result, show, required_format, kwargs)
     else:
         for idx, result in enumerate(
-            solver.solve_in_rounds(
+            solver.solve_in_rounds(specs, out=output, timers=args.timers, stats=args.stats)
-                specs, out=output, models=models, timers=args.timers, stats=args.stats
-            )
         ):
             if "solutions" in show:
                 tty.msg("ROUND {0}".format(idx))

lib/spack/spack/solver/asp.py

@@ -56,6 +56,35 @@
 parse_files = None
 
 
+#: Data class that contain configuration on what a
+#: clingo solve should output.
+#:
+#: Args:
+#:     timers (bool):  Print out coarse timers for different solve phases.
+#:     stats (bool): Whether to output Clingo's internal solver statistics.
+#:     out: Optional output stream for the generated ASP program.
+#:     setup_only (bool): if True, stop after setup and don't solve (default False).
+OutputConfiguration = collections.namedtuple(
+    "OutputConfiguration", ["timers", "stats", "out", "setup_only"]
+)
+
+#: Default output configuration for a solve
+DEFAULT_OUTPUT_CONFIGURATION = OutputConfiguration(
+    timers=False, stats=False, out=None, setup_only=False
+)
+
+
+def default_clingo_control():
+    """Return a control object with the default settings used in Spack"""
+    control = clingo.Control()
+    control.configuration.configuration = "tweety"
+    control.configuration.solve.models = 0
+    control.configuration.solver.heuristic = "Domain"
+    control.configuration.solve.parallel_mode = "1"
+    control.configuration.solver.opt_strategy = "usc,one"
+    return control
+
+
 # backward compatibility functions for clingo ASTs
 def ast_getter(*names):
     def getter(node):
@@ -520,6 +549,12 @@ def __init__(self, cores=True):
         self.out = llnl.util.lang.Devnull()
         self.cores = cores
 
+        # These attributes are part of the object, but will be reset
+        # at each call to solve
+        self.control = None
+        self.backend = None
+        self.assumptions = None
+
     def title(self, name, char):
         self.out.write("\n")
         self.out.write("%" + (char * 76))
@@ -556,43 +591,31 @@ def fact(self, head):
         if choice:
             self.assumptions.append(atom)
 
-    def solve(
+    def solve(self, setup, specs, reuse=None, output=None, control=None):
-        self,
-        setup,
-        specs,
-        nmodels=0,
-        reuse=None,
-        timers=False,
-        stats=False,
-        out=None,
-        setup_only=False,
-    ):
         """Set up the input and solve for dependencies of ``specs``.
 
         Arguments:
-          setup (SpackSolverSetup): An object to set up the ASP problem.
+            setup (SpackSolverSetup): An object to set up the ASP problem.
-          specs (list): List of ``Spec`` objects to solve for.
+            specs (list): List of ``Spec`` objects to solve for.
-          nmodels (int): Number of models to consider (default 0 for unlimited).
+            reuse (None or list): list of concrete specs that can be reused
-          reuse (None or list): list of concrete specs that can be reused
+            output (None or OutputConfiguration): configuration object to set
-          timers (bool):  Print out coarse timers for different solve phases.
+                the output of this solve.
-          stats (bool): Whether to output Clingo's internal solver statistics.
+            control (clingo.Control): configuration for the solver. If None,
-          out: Optional output stream for the generated ASP program.
+                default values will be used
-          setup_only (bool): if True, stop after setup and don't solve (default False).
+
+        Return:
+            A tuple of the solve result, the timer for the different phases of the
+            solve, and the internal statistics from clingo.
         """
+        output = output or DEFAULT_OUTPUT_CONFIGURATION
         # allow solve method to override the output stream
-        if out is not None:
+        if output.out is not None:
-            self.out = out
+            self.out = output.out
 
         timer = spack.util.timer.Timer()
 
         # Initialize the control object for the solver
-        self.control = clingo.Control()
+        self.control = control or default_clingo_control()
-        self.control.configuration.configuration = "tweety"
-        self.control.configuration.solve.models = nmodels
-        self.control.configuration.solver.heuristic = "Domain"
-        self.control.configuration.solve.parallel_mode = "1"
-        self.control.configuration.solver.opt_strategy = "usc,one"
-
         # set up the problem -- this generates facts and rules
         self.assumptions = []
         with self.control.backend() as backend:
@@ -622,8 +645,8 @@ def visit(node):
             parse_files([path], visit)
 
         # If we're only doing setup, just return an empty solve result
-        if setup_only:
+        if output.setup_only:
-            return Result(specs)
+            return Result(specs), None, None
 
         # Load the file itself
         self.control.load(os.path.join(parent_dir, "concretize.lp"))
@@ -682,18 +705,21 @@ def stringify(x):
             # record the number of models the solver considered
             result.nmodels = len(models)
 
+            # record the possible dependencies in the solve
+            result.possible_dependencies = setup.pkgs
+
         elif cores:
             result.control = self.control
             result.cores.extend(cores)
 
-        if timers:
+        if output.timers:
             timer.write_tty()
             print()
-        if stats:
+        if output.stats:
             print("Statistics:")
             pprint.pprint(self.control.statistics)
 
-        return result
+        return result, timer, self.control.statistics
 
 
 class SpackSolverSetup(object):
@@ -732,6 +758,9 @@ def __init__(self, tests=False):
         # If False allows for input specs that are not solved
         self.concretize_everything = True
 
+        # Set during the call to setup
+        self.pkgs = None
+
     def pkg_version_rules(self, pkg):
         """Output declared versions of a package.
 
@@ -964,7 +993,8 @@ def pkg_rules(self, pkg, tests):
 
         # virtual preferences
         self.virtual_preferences(
-            pkg.name, lambda v, p, i: self.gen.fact(fn.pkg_provider_preference(pkg.name, v, p, i))
+            pkg.name,
+            lambda v, p, i: self.gen.fact(fn.pkg_provider_preference(pkg.name, v, p, i)),
         )
 
     def condition(self, required_spec, imposed_spec=None, name=None, msg=None):
@@ -1063,7 +1093,8 @@ def provider_defaults(self):
         self.gen.h2("Default virtual providers")
         assert self.possible_virtuals is not None
         self.virtual_preferences(
-            "all", lambda v, p, i: self.gen.fact(fn.default_provider_preference(v, p, i))
+            "all",
+            lambda v, p, i: self.gen.fact(fn.default_provider_preference(v, p, i)),
         )
 
     def external_packages(self):
@@ -1798,7 +1829,7 @@ def setup(self, driver, specs, reuse=None):
             if missing_deps:
                 raise spack.spec.InvalidDependencyError(spec.name, missing_deps)
 
-        pkgs = set(possible)
+        self.pkgs = set(possible)
 
         # driver is used by all the functions below to add facts and
         # rules to generate an ASP program.
@@ -1835,7 +1866,7 @@ def setup(self, driver, specs, reuse=None):
         self.flag_defaults()
 
         self.gen.h1("Package Constraints")
-        for pkg in sorted(pkgs):
+        for pkg in sorted(self.pkgs):
             self.gen.h2("Package rules: %s" % pkg)
             self.pkg_rules(pkg, tests=self.tests)
             self.gen.h2("Package preferences: %s" % pkg)
@@ -2215,7 +2246,6 @@ def solve(
         self,
         specs,
         out=None,
-        models=0,
         timers=False,
         stats=False,
         tests=False,
@@ -2225,7 +2255,6 @@ def solve(
         Arguments:
           specs (list): List of ``Spec`` objects to solve for.
           out: Optionally write the generate ASP program to a file-like object.
-          models (int): Number of models to search (default: 0 for unlimited).
           timers (bool): Print out coarse fimers for different solve phases.
           stats (bool): Print out detailed stats from clingo.
           tests (bool or tuple): If True, concretize test dependencies for all packages.
@@ -2237,22 +2266,14 @@ def solve(
         reusable_specs = self._check_input_and_extract_concrete_specs(specs)
         reusable_specs.extend(self._reusable_specs())
         setup = SpackSolverSetup(tests=tests)
-        return self.driver.solve(
+        output = OutputConfiguration(timers=timers, stats=stats, out=out, setup_only=setup_only)
-            setup,
+        result, _, _ = self.driver.solve(setup, specs, reuse=reusable_specs, output=output)
-            specs,
+        return result
-            nmodels=models,
-            reuse=reusable_specs,
-            timers=timers,
-            stats=stats,
-            out=out,
-            setup_only=setup_only,
-        )
 
     def solve_in_rounds(
         self,
         specs,
         out=None,
-        models=0,
         timers=False,
         stats=False,
         tests=False,
@@ -2267,7 +2288,6 @@ def solve_in_rounds(
 
         Arguments:
             specs (list): list of Specs to solve.
-            models (int): number of models to search (default: 0)
             out: Optionally write the generate ASP program to a file-like object.
             timers (bool): print timing if set to True
             stats (bool): print internal statistics if set to True
@@ -2281,16 +2301,10 @@ def solve_in_rounds(
         setup.concretize_everything = False
 
         input_specs = specs
+        output = OutputConfiguration(timers=timers, stats=stats, out=out, setup_only=False)
         while True:
-            result = self.driver.solve(
+            result, _, _ = self.driver.solve(
-                setup,
+                setup, input_specs, reuse=reusable_specs, output=output
-                input_specs,
-                nmodels=models,
-                reuse=reusable_specs,
-                timers=timers,
-                stats=stats,
-                out=out,
-                setup_only=False,
             )
             yield result
 

lib/spack/spack/test/concretize.py

@@ -1700,7 +1700,7 @@ def test_version_weight_and_provenance(self):
         with spack.config.override("concretizer:reuse", True):
             solver = spack.solver.asp.Solver()
             setup = spack.solver.asp.SpackSolverSetup()
-            result = solver.driver.solve(setup, [root_spec], reuse=reusable_specs, out=sys.stdout)
+            result, _, _ = solver.driver.solve(setup, [root_spec], reuse=reusable_specs)
             # The result here should have a single spec to build ('a')
             # and it should be using b@1.0 with a version badness of 2
             # The provenance is:
@@ -1731,7 +1731,7 @@ def test_not_reusing_incompatible_os_or_compiler(self):
         with spack.config.override("concretizer:reuse", True):
             solver = spack.solver.asp.Solver()
             setup = spack.solver.asp.SpackSolverSetup()
-            result = solver.driver.solve(setup, [root_spec], reuse=reusable_specs, out=sys.stdout)
+            result, _, _ = solver.driver.solve(setup, [root_spec], reuse=reusable_specs)
         concrete_spec = result.specs[0]
         assert concrete_spec.satisfies("%gcc@4.5.0")
         assert concrete_spec.satisfies("os=debian6")

share/spack/spack-completion.bash

@@ -1670,7 +1670,7 @@ _spack_restage() {
 _spack_solve() {
     if $list_options
     then
-        SPACK_COMPREPLY="-h --help --show --models -l --long -L --very-long -I --install-status -y --yaml -j --json -c --cover -N --namespaces -t --types --timers --stats -U --fresh --reuse"
+        SPACK_COMPREPLY="-h --help --show -l --long -L --very-long -I --install-status -y --yaml -j --json -c --cover -N --namespaces -t --types --timers --stats -U --fresh --reuse"
     else
         _all_packages
     fi