_project.py: Add get_default_target() and get_default_targets() methods

_frontend/cli.py: Use new methods.

Based on patches by Phillip Smyth.

3 files changed, 113 insertions, 40 deletions

diff --git a/buildstream/_context.py b/buildstream/_context.py
index 8b9f47bd6..f14f6b746 100644
--- a/buildstream/_context.py
+++ b/buildstream/_context.py
@@ -32,7 +32,7 @@ from ._message import Message, MessageType
 from ._profile import Topics, profile_start, profile_end
 from ._artifactcache import ArtifactCache
 from ._cas import CASCache
-from ._workspaces import Workspaces, WorkspaceProjectCache, WORKSPACE_PROJECT_FILE
+from ._workspaces import Workspaces, WorkspaceProjectCache
 from .plugin import _plugin_lookup
 from .sandbox import SandboxRemote
 
@@ -657,20 +657,6 @@ class Context():
             self._cascache = CASCache(self.artifactdir)
         return self._cascache
 
-    # guess_element()
-    #
-    # Attempts to interpret which element the user intended to run commands on
-    #
-    # Returns:
-    #    (str) The name of the element, or None if no element can be guessed
-    def guess_element(self):
-        workspace_project_dir, _ = utils._search_upward_for_files(self._directory, [WORKSPACE_PROJECT_FILE])
-        if workspace_project_dir:
-            workspace_project = self._workspace_project_cache.get(workspace_project_dir)
-            return workspace_project.get_default_element()
-        else:
-            return None
-
 
 # _node_get_option_str()
 #
diff --git a/buildstream/_frontend/cli.py b/buildstream/_frontend/cli.py
index 5e8aee51b..6674b14a6 100644
--- a/buildstream/_frontend/cli.py
+++ b/buildstream/_frontend/cli.py
@@ -342,7 +342,15 @@ def init(app, project_name, format_version, element_path, force):
                 type=click.Path(readable=False))
 @click.pass_obj
 def build(app, elements, all_, track_, track_save, track_all, track_except, track_cross_junctions):
-    """Build elements in a pipeline"""
+    """Build elements in a pipeline
+
+    Specifying no elements will result in building the default targets
+    of the project. If no default targets are configured, all project
+    elements will be built.
+
+    When this command is executed from a workspace directory, the default
+    is to build the workspace element.
+    """
 
     if (track_except or track_cross_junctions) and not (track_ or track_all):
         click.echo("ERROR: The --track-except and --track-cross-junctions options "
@@ -354,9 +362,7 @@ def build(app, elements, all_, track_, track_save, track_all, track_except, trac
 
     with app.initialized(session_name="Build"):
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         if track_all:
             track_ = elements
@@ -383,6 +389,13 @@ def build(app, elements, all_, track_, track_save, track_all, track_except, trac
 def pull(app, elements, deps, remote):
     """Pull a built artifact from the configured remote artifact cache.
 
+    Specifying no elements will result in pulling the default targets
+    of the project. If no default targets are configured, all project
+    elements will be pulled.
+
+    When this command is executed from a workspace directory, the default
+    is to pull the workspace element.
+
     By default the artifact will be pulled one of the configured caches
     if possible, following the usual priority order. If the `--remote` flag
     is given, only the specified cache will be queried.
@@ -396,9 +409,7 @@ def pull(app, elements, deps, remote):
 
     with app.initialized(session_name="Pull"):
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         app.stream.pull(elements, selection=deps, remote=remote)
 
@@ -418,6 +429,13 @@ def pull(app, elements, deps, remote):
 def push(app, elements, deps, remote):
     """Push a built artifact to a remote artifact cache.
 
+    Specifying no elements will result in pushing the default targets
+    of the project. If no default targets are configured, all project
+    elements will be pushed.
+
+    When this command is executed from a workspace directory, the default
+    is to push the workspace element.
+
     The default destination is the highest priority configured cache. You can
     override this by passing a different cache URL with the `--remote` flag.
 
@@ -433,9 +451,7 @@ def push(app, elements, deps, remote):
     """
     with app.initialized(session_name="Push"):
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         app.stream.push(elements, selection=deps, remote=remote)
 
@@ -462,6 +478,13 @@ def push(app, elements, deps, remote):
 def show(app, elements, deps, except_, order, format_):
     """Show elements in the pipeline
 
+    Specifying no elements will result in showing the default targets
+    of the project. If no default targets are configured, all project
+    elements will be shown.
+
+    When this command is executed from a workspace directory, the default
+    is to show the workspace element.
+
     By default this will show all of the dependencies of the
     specified target element.
 
@@ -508,9 +531,7 @@ def show(app, elements, deps, except_, order, format_):
     """
     with app.initialized():
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         dependencies = app.stream.load_selection(elements,
                                                  selection=deps,
@@ -550,6 +571,9 @@ def show(app, elements, deps, except_, order, format_):
 def shell(app, element, sysroot, mount, isolate, build_, cli_buildtree, command):
     """Run a command in the target element's sandbox environment
 
+    When this command is executed from a workspace directory, the default
+    is to shell into the workspace element.
+
     This will stage a temporary sysroot for running the target
     element, assuming it has already been built and all required
     artifacts are in the local cache.
@@ -583,7 +607,7 @@ def shell(app, element, sysroot, mount, isolate, build_, cli_buildtree, command)
 
     with app.initialized():
         if not element:
-            element = app.context.guess_element()
+            element = app.project.get_default_target()
             if not element:
                 raise AppError('Missing argument "ELEMENT".')
 
@@ -648,6 +672,9 @@ def shell(app, element, sysroot, mount, isolate, build_, cli_buildtree, command)
 @click.pass_obj
 def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
     """Checkout a built artifact to the specified location
+
+    When this command is executed from a workspace directory, the default
+    is to checkout the artifact of the workspace element.
     """
     from ..element import Scope
 
@@ -673,7 +700,7 @@ def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
 
     with app.initialized():
         if not element:
-            element = app.context.guess_element()
+            element = app.project.get_default_target()
             if not element:
                 raise AppError('Missing argument "ELEMENT".')
 
@@ -714,6 +741,13 @@ def source():
 def source_fetch(app, elements, deps, track_, except_, track_cross_junctions):
     """Fetch sources required to build the pipeline
 
+    Specifying no elements will result in fetching the default targets
+    of the project. If no default targets are configured, all project
+    elements will be fetched.
+
+    When this command is executed from a workspace directory, the default
+    is to fetch the workspace element.
+
     By default this will only try to fetch sources which are
     required for the build plan of the specified target element,
     omitting sources for any elements which are already built
@@ -739,9 +773,7 @@ def source_fetch(app, elements, deps, track_, except_, track_cross_junctions):
 
     with app.initialized(session_name="Fetch"):
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         app.stream.fetch(elements,
                          selection=deps,
@@ -769,6 +801,15 @@ def source_track(app, elements, deps, except_, cross_junctions):
     """Consults the specified tracking branches for new versions available
     to build and updates the project with any newly available references.
 
+    Specifying no elements will result in tracking the default targets
+    of the project. If no default targets are configured, all project
+    elements will be tracked.
+
+    When this command is executed from a workspace directory, the default
+    is to track the workspace element.
+
+    If no default is declared, all elements in the project will be tracked
+
     By default this will track just the specified element, but you can also
     update a whole tree of dependencies in one go.
 
@@ -780,9 +821,7 @@ def source_track(app, elements, deps, except_, cross_junctions):
     """
     with app.initialized(session_name="Track"):
         if not elements:
-            guessed_target = app.context.guess_element()
-            if guessed_target:
-                elements = (guessed_target,)
+            elements = app.project.get_default_targets()
 
         # Substitute 'none' for 'redirect' so that element redirections
         # will be done
@@ -818,6 +857,9 @@ def source_track(app, elements, deps, except_, cross_junctions):
 def source_checkout(app, element, location, force, deps, fetch_, except_,
                     tar, build_scripts):
     """Checkout sources of an element to the specified location
+
+    When this command is executed from a workspace directory, the default
+    is to checkout the sources of the workspace element.
     """
     if not element and not location:
         click.echo("ERROR: LOCATION is not specified", err=True)
@@ -830,7 +872,7 @@ def source_checkout(app, element, location, force, deps, fetch_, except_,
 
     with app.initialized():
         if not element:
-            element = app.context.guess_element()
+            element = app.project.get_default_target()
             if not element:
                 raise AppError('Missing argument "ELEMENT".')
 
@@ -896,7 +938,7 @@ def workspace_close(app, remove_dir, all_, elements):
         if not (all_ or elements):
             # NOTE: I may need to revisit this when implementing multiple projects
             # opening one workspace.
-            element = app.context.guess_element()
+            element = app.project.get_default_target()
             if element:
                 elements = (element,)
             else:
@@ -957,7 +999,7 @@ def workspace_reset(app, soft, track_, all_, elements):
     with app.initialized():
 
         if not (all_ or elements):
-            element = app.context.guess_element()
+            element = app.project.get_default_target()
             if element:
                 elements = (element,)
             else:
diff --git a/buildstream/_project.py b/buildstream/_project.py
index 1492fde77..3ec141d58 100644
--- a/buildstream/_project.py
+++ b/buildstream/_project.py
@@ -104,6 +104,9 @@ class Project():
         # Absolute path to where elements are loaded from within the project
         self.element_path = None
 
+        # Default target elements
+        self._default_targets = None
+
         # ProjectRefs for the main refs and also for junctions
         self.refs = ProjectRefs(self.directory, 'project.refs')
         self.junction_refs = ProjectRefs(self.directory, 'junction.refs')
@@ -228,7 +231,7 @@ class Project():
             'element-path', 'variables',
             'environment', 'environment-nocache',
             'split-rules', 'elements', 'plugins',
-            'aliases', 'name',
+            'aliases', 'name', 'defaults',
             'artifacts', 'options',
             'fail-on-overlap', 'shell', 'fatal-warnings',
             'ref-storage', 'sandbox', 'mirrors', 'remote-execution',
@@ -391,6 +394,44 @@ class Project():
         # Reset the element loader state
         Element._reset_load_state()
 
+    # get_default_target()
+    #
+    # Attempts to interpret which element the user intended to run a command on.
+    # This is for commands that only accept a single target element and thus,
+    # this only uses the workspace element (if invoked from workspace directory)
+    # and does not use the project default targets.
+    #
+    def get_default_target(self):
+        return self._invoked_from_workspace_element
+
+    # get_default_targets()
+    #
+    # Attempts to interpret which elements the user intended to run a command on.
+    # This is for commands that accept multiple target elements.
+    #
+    def get_default_targets(self):
+
+        # If _invoked_from_workspace_element has a value,
+        # a workspace element was found before a project config
+        # Therefore the workspace does not contain a project
+        if self._invoked_from_workspace_element:
+            return (self._invoked_from_workspace_element,)
+
+        # Default targets from project configuration
+        if self._default_targets:
+            return tuple(self._default_targets)
+
+        # If default targets are not configured, default to all project elements
+        default_targets = []
+        for root, _, files in os.walk(self.element_path):
+            for file in files:
+                if file.endswith(".bst"):
+                    rel_dir = os.path.relpath(root, self.element_path)
+                    rel_file = os.path.join(rel_dir, file).lstrip("./")
+                    default_targets.append(rel_file)
+
+        return tuple(default_targets)
+
     # _load():
     #
     # Loads the project configuration file in the project
@@ -456,6 +497,10 @@ class Project():
         self.config.options = OptionPool(self.element_path)
         self.first_pass_config.options = OptionPool(self.element_path)
 
+        defaults = _yaml.node_get(pre_config_node, Mapping, 'defaults')
+        _yaml.node_validate(defaults, ['targets'])
+        self._default_targets = _yaml.node_get(defaults, list, "targets")
+
         # Fatal warnings
         self._fatal_warnings = _yaml.node_get(pre_config_node, list, 'fatal-warnings', default_value=[])