Get version number w/o pkg_resources

This removes most of the usages of pkg_resources from the codebase, helping
the goal of getting rid of that completely.

With this change, version number is generated during install and embedded into
`__version__` which is then imported by root level `__init__`. From there,
it is used by other parts of the codebase when needed.

Generated `__version__` file is ignored and not tracked by git to prevent
unnecessary 'changes' messages and accidental commits of that file.

6 files changed, 19 insertions, 11 deletions

diff --git a/.gitignore b/.gitignore
index b99e24897..1bfb5c411 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,6 @@ tmp
 
 # Integration test results
 /integration-tests/*results/
+
+# Generated version file
+buildstream/__version__.py
\ No newline at end of file
diff --git a/buildstream/__init__.py b/buildstream/__init__.py
index cf13655fa..733350bdd 100644
--- a/buildstream/__init__.py
+++ b/buildstream/__init__.py
@@ -19,6 +19,7 @@
 #        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
 
 # Plugin author facing APIs
+from .__version__ import __version__
 from .utils import UtilError, ProgramNotFoundError
 from .sandbox import Sandbox, SandboxFlags
 from .plugin import Plugin
diff --git a/buildstream/_frontend/main.py b/buildstream/_frontend/main.py
index 5944a49ac..b2bf493ff 100644
--- a/buildstream/_frontend/main.py
+++ b/buildstream/_frontend/main.py
@@ -20,7 +20,6 @@
 import os
 import sys
 import click
-import pkg_resources  # From setuptools
 from contextlib import contextmanager
 from blessings import Terminal
 from click import UsageError
@@ -37,14 +36,12 @@ from .._pipeline import Pipeline, PipelineError
 from .._scheduler import Scheduler
 from .._profile import Topics, profile_start, profile_end
 from .. import _yaml
+from .. import __version__ as build_stream_version
 
 # Import frontend assets
 from . import Profile, LogLine, Status
 from .complete import main_bashcomplete, complete_path, CompleteUnhandled
 
-# Some globals resolved for default arguments in the cli
-build_stream_version = pkg_resources.require("buildstream")[0].version
-
 # Intendation for all logging
 INDENT = 4
 
diff --git a/buildstream/_frontend/widget.py b/buildstream/_frontend/widget.py
index 1dccd0059..d61f338df 100644
--- a/buildstream/_frontend/widget.py
+++ b/buildstream/_frontend/widget.py
@@ -24,12 +24,12 @@ from contextlib import ExitStack
 from mmap import mmap
 
 import click
-import pkg_resources
 from ruamel import yaml
 
 from . import Profile
 from .. import Element, Scope, Consistency
 from .. import _yaml
+from .. import __version__ as bst_version
 from .._exceptions import ImplError
 from .._message import MessageType
 from ..plugin import _plugin_lookup
@@ -432,12 +432,11 @@ class LogLine(Widget):
         context = pipeline.context
         project = pipeline.project
         starttime = datetime.datetime.now()
-        bst = pkg_resources.require("buildstream")[0]
         text = ''
 
         # Main invocation context
         text += '\n'
-        text += self.content_profile.fmt("BuildStream Version {}\n".format(bst.version), bold=True)
+        text += self.content_profile.fmt("BuildStream Version {}\n".format(bst_version), bold=True)
         values = OrderedDict()
         values["Session Start"] = starttime.strftime('%A, %d-%m-%Y at %H:%M:%S')
         values["Project"] = "{} ({})".format(project.name, project.directory)
diff --git a/buildstream/utils.py b/buildstream/utils.py
index 3a13dea6c..da67f9c10 100644
--- a/buildstream/utils.py
+++ b/buildstream/utils.py
@@ -36,9 +36,9 @@ import tempfile
 import itertools
 from contextlib import contextmanager
 
-import pkg_resources
 import psutil
 
+from . import __version__
 from . import _signals
 from ._exceptions import BstError, ErrorDomain
 
@@ -455,8 +455,7 @@ def get_bst_version():
        (int): The major version
        (int): The minor version
     """
-    package = pkg_resources.require("buildstream")[0]
-    versions = package.version.split('.')[:2]
+    versions = __version__.split('.')[:2]
 
     return (int(versions[0]), int(versions[1]))
 
diff --git a/setup.py b/setup.py
index 3e9f88545..01b834bd9 100755
--- a/setup.py
+++ b/setup.py
@@ -133,6 +133,12 @@ if not os.environ.get('BST_ARTIFACTS_ONLY', ''):
         'bst = buildstream._frontend:cli'
     ]
 
+_version_template = """\
+# coding: utf-8
+# file generated by setuptools_scm
+# don't change, don't track in version control
+__version__ = {version!r}
+"""
 
 #####################################################
 #    Monkey-patching setuptools for performance     #
@@ -176,7 +182,10 @@ ScriptWriter.get_args = get_args
 setup(name='BuildStream',
       description='A framework for modelling build pipelines in YAML',
       license='LGPL',
-      use_scm_version=True,
+      use_scm_version={
+          'write_to': "buildstream/__version__.py",
+          'write_to_template': _version_template,
+      },
       packages=find_packages(),
       package_data={'buildstream': ['plugins/*/*.py', 'plugins/*/*.yaml',
                                     'data/*.yaml', 'data/*.sh.in']},