build: add a --dry-run option that only prints commands

This is useful to reproduce a build in the shell. Modified
environment variables by recipes using new_env and append_env
are not yet exposed correctly

3 files changed, 22 insertions, 10 deletions

diff --git a/cerbero/build/oven.py b/cerbero/build/oven.py
index b73c48a..a76582a 100644
--- a/cerbero/build/oven.py
+++ b/cerbero/build/oven.py
@@ -45,7 +45,7 @@ class Oven (object):
     STEP_TPL = '[(%s/%s) %s -> %s ]'
 
     def __init__(self, recipes, cookbook, force=False, no_deps=False,
-                 missing_files=False):
+                 missing_files=False, dry_run=False):
         if isinstance(recipes, Recipe):
             recipes = [recipes]
         self.recipes = recipes
@@ -53,6 +53,7 @@ class Oven (object):
         self.force = force
         self.no_deps = no_deps
         self.missing_files = missing_files
+        shell.DRY_RUN = dry_run
 
     def start_cooking(self):
         '''
diff --git a/cerbero/commands/build.py b/cerbero/commands/build.py
index 3ea9ffa..a0c62f9 100644
--- a/cerbero/commands/build.py
+++ b/cerbero/commands/build.py
@@ -35,7 +35,10 @@ class Build(Command):
                 ArgparseArgument('--missing-files', action='store_true',
                     default=False,
                     help=_('prints a list of files installed that are '
-                           'listed in the recipe'))]
+                           'listed in the recipe')),
+                ArgparseArgument('--dry-run', action='store_true',
+                    default=False,
+                    help=_('only print commands instead of running them '))]
             if force is None:
                 args.append(
                     ArgparseArgument('--force', action='store_true',
@@ -58,15 +61,16 @@ class Build(Command):
         if self.no_deps is None:
             self.no_deps = args.no_deps
         self.runargs(config, args.recipe, args.missing_files, self.force,
-                     self.no_deps)
+                     self.no_deps, dry_run=args.dry_run)
 
     def runargs(self, config, recipes, missing_files=False, force=False,
-                no_deps=False, cookbook=None):
+                no_deps=False, cookbook=None, dry_run=False):
         if cookbook is None:
             cookbook = CookBook(config)
 
         oven = Oven(recipes, cookbook, force=self.force,
-                    no_deps=self.no_deps, missing_files=missing_files)
+                    no_deps=self.no_deps, missing_files=missing_files,
+                    dry_run=dry_run)
         oven.start_cooking()
 
 
diff --git a/cerbero/utils/shell.py b/cerbero/utils/shell.py
index 8e23216..46e3240 100644
--- a/cerbero/utils/shell.py
+++ b/cerbero/utils/shell.py
@@ -30,6 +30,7 @@ import shutil
 
 from cerbero.enums import Platform
 from cerbero.utils import _, system_info, to_unixpath
+from cerbero.utils import messages as m
 from cerbero.errors import FatalError
 
 
@@ -39,6 +40,7 @@ TAR = 'tar'
 
 PLATFORM = system_info()[0]
 LOGFILE = None  # open('/tmp/cerbero.log', 'w+')
+DRY_RUN = False
 
 
 class StdOut:
@@ -76,7 +78,7 @@ def call(cmd, cmd_dir='.', fail=True):
     @type fail: bool
     '''
     try:
-        logging.info("Running command '%s'" % cmd)
+        m.message("Running command '%s'" % cmd)
         shell = True
         if PLATFORM == Platform.WINDOWS:
             # windows do not understand ./
@@ -89,10 +91,15 @@ def call(cmd, cmd_dir='.', fail=True):
             # Disable shell which uses cmd.exe
             shell = False
         stream = LOGFILE or sys.stdout
-        ret = subprocess.check_call(cmd, cwd=cmd_dir,
-                                    stderr=subprocess.STDOUT,
-                                    stdout=StdOut(stream),
-                                    env=os.environ.copy(), shell=shell)
+        if DRY_RUN:
+            # write to sdterr so it's filtered more easilly
+            m.error ("cd %s && %s && cd %s" % (cmd_dir, cmd, os.getcwd()))
+            ret = 0
+        else:
+            ret = subprocess.check_call(cmd, cwd=cmd_dir,
+                                       stderr=subprocess.STDOUT,
+                                       stdout=StdOut(stream),
+                                       env=os.environ.copy(), shell=shell)
     except subprocess.CalledProcessError:
         if fail:
             raise FatalError(_("Error running command: %s") % cmd)