--- libvirt-sandbox/libvirt-sandbox-builder.c | 1 + 1 file changed, 1 insertion(+) diff --git a/libvirt-sandbox/libvirt-sandbox-builder.c b/libvirt-sandbox/libvirt-sandbox-builder.c index ea7d064..cbfa780 100644 --- a/libvirt-sandbox/libvirt-sandbox-builder.c +++ b/libvirt-sandbox/libvirt-sandbox-builder.c @@ -759,6 +759,7 @@ gboolean gvir_sandbox_builder_clean_post_stop(GVirSandboxBuilder *builder, g_object_unref(enumerator); g_object_unref(libsFile); g_free(libsdir); + g_free(dskfile); return ret; } -- 2.1.4

--- libvirt-sandbox/image/cli.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py index 776b71f..75daf72 100755 --- a/libvirt-sandbox/image/cli.py +++ b/libvirt-sandbox/image/cli.py @@ -80,7 +80,7 @@ def delete(args): source.delete_template(template=tmpl, templatedir=args.template_dir) except Exception,e: - print "Delete Error %s", str(e) + print "Delete Error %s" % str(e) def create(args): try: -- 2.1.4

--- libvirt-sandbox/image/sources/DockerSource.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libvirt-sandbox/image/sources/DockerSource.py b/libvirt-sandbox/image/sources/DockerSource.py index ab0b765..6c02cc3 100644 --- a/libvirt-sandbox/image/sources/DockerSource.py +++ b/libvirt-sandbox/image/sources/DockerSource.py @@ -243,7 +243,7 @@ class DockerSource(Source): def create_template(self, template, templatedir, connect=None, format=None): if format is None: - format = self.default_disk_format + format = "qcow2" self._check_disk_format(format) imagelist = self._get_image_list(template, templatedir) imagelist.reverse() -- 2.1.4

This hook in the source allows additional cleanup to take place once the run command is terminated. This is not used by the docker source, but will be used by the virt-builder one --- libvirt-sandbox/image/cli.py | 1 + libvirt-sandbox/image/sources/Source.py | 12 ++++++++++++ 2 files changed, 13 insertions(+) diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py index 75daf72..e991e2d 100755 --- a/libvirt-sandbox/image/cli.py +++ b/libvirt-sandbox/image/cli.py @@ -142,6 +142,7 @@ def run(args): cmd = cmd + params + ['--'] + commandToRun subprocess.call(cmd) os.unlink(diskfile) + source.post_run(tmpl, args.template_dir, name) except Exception,e: print "Run Error %s" % str(e) diff --git a/libvirt-sandbox/image/sources/Source.py b/libvirt-sandbox/image/sources/Source.py index 33feb7c..20f4af0 100644 --- a/libvirt-sandbox/image/sources/Source.py +++ b/libvirt-sandbox/image/sources/Source.py @@ -102,3 +102,15 @@ class Source(): Get the dict of environment variables to set """ pass + + def post_run(self, template, templatedir, imagename): + """ + :param template: libvirt_sandbox.template.Template object + :param templatedir: local directory path in which to find template + :param imagename: name of the image that just stopped running + + Hook called after the image has been stopped. By default is doesn't + do anything, subclasses can override this to do some additional + cleanup. + """ + pass -- 2.1.4

Formatting a disk is a generic operation that will be needed by other sources, at least a virt-builder one. --- libvirt-sandbox/image/sources/DockerSource.py | 14 +------------- libvirt-sandbox/image/sources/Source.py | 16 ++++++++++++++++ 2 files changed, 17 insertions(+), 13 deletions(-) diff --git a/libvirt-sandbox/image/sources/DockerSource.py b/libvirt-sandbox/image/sources/DockerSource.py index 6c02cc3..41df7a7 100644 --- a/libvirt-sandbox/image/sources/DockerSource.py +++ b/libvirt-sandbox/image/sources/DockerSource.py @@ -261,7 +261,7 @@ class DockerSource(Source): subprocess.call(cmd) if parentImage is None: - self._format_disk(templateImage,format,connect) + self.format_disk(templateImage,format,connect) self._extract_tarballs(templatedir + "/" + imagetagid + "/template.",format,connect) parentImage = templateImage @@ -299,18 +299,6 @@ class DockerSource(Source): imagetagid = parent return imagelist - def _format_disk(self,disk,format,connect): - cmd = ['virt-sandbox'] - if connect is not None: - cmd.append("-c") - cmd.append(connect) - cmd.append("-p") - params = ['--disk=file:disk_image=%s,format=%s' %(disk,format), - '/sbin/mkfs.ext3', - '/dev/disk/by-tag/disk_image'] - cmd = cmd + params - subprocess.call(cmd) - def _extract_tarballs(self,directory,format,connect): tarfile = directory + "tar.gz" diskfile = directory + "qcow2" diff --git a/libvirt-sandbox/image/sources/Source.py b/libvirt-sandbox/image/sources/Source.py index 20f4af0..444baa3 100644 --- a/libvirt-sandbox/image/sources/Source.py +++ b/libvirt-sandbox/image/sources/Source.py @@ -21,6 +21,7 @@ # Author: Eren Yagdiran <erenyagdiran(a)gmail.com&gt; from abc import ABCMeta, abstractmethod +import subprocess class Source(): '''The Source class defines the base interface for @@ -114,3 +115,18 @@ class Source(): cleanup. """ pass + + + # Utility functions to share between the sources. + + def format_disk(self,disk,format,connect): + cmd = ['virt-sandbox'] + if connect is not None: + cmd.append("-c") + cmd.append(connect) + cmd.append("-p") + params = ['--disk=file:disk_image=%s,format=%s' %(disk,format), + '/sbin/mkfs.ext3', + '/dev/disk/by-tag/disk_image'] + cmd = cmd + params + subprocess.call(cmd) -- 2.1.4

To compute the source class name from the URI scheme, we need to be a bit smarter to have a nice scheme for sources like the virt-builder one. In order to have a scheme like virt-builder:// and a class name like VirtBuilderSource, strip the non-word characters from the scheme and camel case the words. --- libvirt-sandbox/image/template.py | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libvirt-sandbox/image/template.py b/libvirt-sandbox/image/template.py index 17da6c0..4713b0a 100644 --- a/libvirt-sandbox/image/template.py +++ b/libvirt-sandbox/image/template.py @@ -21,6 +21,7 @@ import urlparse import importlib +import re class Template(object): @@ -56,10 +57,13 @@ class Template(object): self.params = {} def get_source_impl(self): + p = re.compile("\W") + sourcename = "".join([i.capitalize() for i in p.split(self.source)]) + mod = importlib.import_module( "libvirt_sandbox.image.sources." + - self.source.capitalize() + "Source") - classname = self.source.capitalize() + "Source" + sourcename + "Source") + classname = sourcename + "Source" classimpl = getattr(mod, classname) return classimpl() -- 2.1.4

Allow virt-sandbox-image to pull templates from virt-builder and run sandboxes on top of them. --- libvirt-sandbox.spec.in | 1 + libvirt-sandbox/image/cli.py | 1 + libvirt-sandbox/image/sources/Makefile.am | 1 + libvirt-sandbox/image/sources/VirtBuilderSource.py | 136 +++++++++++++++++++++ libvirt-sandbox/image/template.py | 2 + 5 files changed, 141 insertions(+) create mode 100644 libvirt-sandbox/image/sources/VirtBuilderSource.py diff --git a/libvirt-sandbox.spec.in b/libvirt-sandbox.spec.in index 54fde55..f84eabc 100644 --- a/libvirt-sandbox.spec.in +++ b/libvirt-sandbox.spec.in @@ -36,6 +36,7 @@ Requires: systemd >= 198 Requires: pygobject3-base Requires: libselinux-python Requires: %{name}-libs = %{version}-%{release} +Requires: %{_bindir}/virt-builder %package libs Group: Development/Libraries diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py index e991e2d..fb1104a 100755 --- a/libvirt-sandbox/image/cli.py +++ b/libvirt-sandbox/image/cli.py @@ -188,6 +188,7 @@ Example supported URI formats: docker:///ubuntu?tag=15.04 docker://username:password@index.docker.io/private/image docker://registry.access.redhat.com/rhel6 + virt-builder:///fedora-20 """) return parser diff --git a/libvirt-sandbox/image/sources/Makefile.am b/libvirt-sandbox/image/sources/Makefile.am index 069557d..52e9a7e 100644 --- a/libvirt-sandbox/image/sources/Makefile.am +++ b/libvirt-sandbox/image/sources/Makefile.am @@ -4,6 +4,7 @@ pythonimage_DATA = \ __init__.py \ Source.py \ DockerSource.py \ + VirtBuilderSource.py \ $(NULL) EXTRA_DIST = $(pythonimage_DATA) diff --git a/libvirt-sandbox/image/sources/VirtBuilderSource.py b/libvirt-sandbox/image/sources/VirtBuilderSource.py new file mode 100644 index 0000000..4a7e383 --- /dev/null +++ b/libvirt-sandbox/image/sources/VirtBuilderSource.py @@ -0,0 +1,136 @@ +#!/usr/bin/python +# +# Copyright (C) 2015 SUSE LLC +# +# This library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# This library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with this library; if not, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA +# +# Author: Cedric Bosdonnat <cbosdonnat(a)suse.com&gt; +# + +from Source import Source +import os +import os.path +import subprocess + +class VirtBuilderSource(Source): + + def _get_template_name(self, template): + # We shouldn't have '/' in the names, but let's make sure + # nobody can try to alter the folders structure later. + return template.path[1:].replace('/', '_') + + def download_template(self, template, templatedir): + # We don't do anything here: virt-builder will do it for us in + # the create action + pass + + def _check_disk_format(self,format): + supportedFormats = ['qcow2', 'raw'] + if not format in supportedFormats: + raise ValueError(["Unsupported image format %s" % format]) + + def create_template(self, template, templatedir, + connect=None, format=None): + # FIXME Force qcow2 format: do we really want people to mess with that? + if not os.path.exists(templatedir): + os.makedirs(templatedir) + + # Get the image using virt-builder + templatename = self._get_template_name(template) + imagepath_original = "%s/%s-original.qcow2" % (templatedir, templatename) + imagepath = "%s/%s.%s" % (templatedir, templatename, format) + cmd = ["virt-builder", templatename, + "-o", imagepath_original, "--format", "qcow2"] + subprocess.call(cmd) + + # We need to convert this image into a single partition one. + tarfile = "%s/%s.tar" % (templatedir, templatename) + cmd = ["virt-tar-out", "-a", imagepath_original, "/", tarfile] + subprocess.call(cmd) + + os.unlink(imagepath_original) + + cmd = ["qemu-img", "create", "-q", "-f", format, imagepath, "10G"] + subprocess.call(cmd) + + self.format_disk(imagepath, format, connect) + self._extract_tarball(imagepath, format, tarfile, connect) + os.unlink(tarfile) + + + def delete_template(self, template, templatedir): + # Check for running sandboxes using this template before killing it + images = self._get_template_uses(template, templatedir) + if len(images) != 0: + imagesStr = ", ".join(images) + raise ValueError(["Images still using the template: %s" % imagesStr]) + + os.unlink("%s/%s.qcow2" % (templatedir, self._get_template_name(template))) + os.unlink("%s/%s.uses" % (templatedir, self._get_template_name(template))) + + def _get_template_uses(self, template, templatedir): + uses = open("%s/%s.uses" % (templatedir, self._get_template_name(template)), "r") + lines = uses.read() + uses.close() + return [l for l in lines.split("\n") if l != ""] + + def post_run(self, template, templatedir, imagename): + images = self._get_template_uses(template, templatedir) + images.remove(imagename) + + uses = open("%s/%s.uses" % (templatedir, self._get_template_name(template)), "w") + uses.write("\n".join(images)) + uses.close() + + def get_command(self, template, templatedir, userargs): + return userargs + + def get_disk(self,template, templatedir, imagedir, sandboxname): + diskfile = "%s/%s.qcow2" % (templatedir, self._get_template_name(template)) + tempfile = imagedir + "/" + sandboxname + ".qcow2" + if not os.path.exists(imagedir): + os.makedirs(imagedir) + cmd = ["qemu-img", "create", "-q", + "-f", "qcow2", + "-o", "backing_fmt=qcow2,backing_file=%s" % diskfile, + tempfile] + subprocess.call(cmd) + + # Add the image to the uses files + uses = open("%s/%s.uses" % (templatedir, + self._get_template_name(template)), "a") + uses.write("%s\n" % sandboxname) + uses.close() + return tempfile + + def get_env(self,template, templatedir): + return [] + + def _extract_tarball(self, diskfile, format, tarfile, connect): + cmd = ['virt-sandbox'] + if connect is not None: + cmd.append("-c") + cmd.append(connect) + cmd.append("-p") + params = ['-m', + 'host-image:/mnt=%s,format=%s' % (diskfile, format), + '--', + '/bin/tar', + 'xf', + '%s' % tarfile, + '-C', + '/mnt'] + cmd = cmd + params + subprocess.call(cmd) diff --git a/libvirt-sandbox/image/template.py b/libvirt-sandbox/image/template.py index 4713b0a..efdd845 100644 --- a/libvirt-sandbox/image/template.py +++ b/libvirt-sandbox/image/template.py @@ -43,6 +43,8 @@ class Template(object): docker:///ubuntu docker+https://index.docker.io/ubuntu?tag=latest + + virt-builder:///fedora-20 """ self.source = source -- 2.1.4

To provide a smooth user experience, run automatically calls create if needed and create automatically calls download if needed. --- libvirt-sandbox/image/cli.py | 18 +++++++++++++++--- libvirt-sandbox/image/sources/DockerSource.py | 16 ++++++++++++++++ libvirt-sandbox/image/sources/Source.py | 22 ++++++++++++++++++++++ libvirt-sandbox/image/sources/VirtBuilderSource.py | 7 +++++++ 4 files changed, 60 insertions(+), 3 deletions(-) diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py index fb1104a..f4472d9 100755 --- a/libvirt-sandbox/image/cli.py +++ b/libvirt-sandbox/image/cli.py @@ -42,6 +42,7 @@ if os.geteuid() == 0: else: default_template_dir = os.environ['HOME'] + "/.local/share/libvirt/templates" default_image_dir = os.environ['HOME'] + "/.local/share/libvirt/images" +default_format = "qcow2" debug = False verbose = False @@ -86,10 +87,18 @@ def create(args): try: tmpl = template.Template.from_uri(args.template) source = tmpl.get_source_impl() + + if not source.was_downloaded(tmpl, args.template_dir): + download(args) + + fmt = default_format + if "format" in vars(args): + fmt = args.format + source.create_template(template=tmpl, templatedir=args.template_dir, connect=args.connect, - format=args.format) + format=fmt) except Exception,e: print "Create Error %s" % str(e) @@ -97,10 +106,13 @@ def run(args): try: if args.connect is not None: check_connect(args.connect) - tmpl = template.Template.from_uri(args.template) source = tmpl.get_source_impl() + # Create the template image if needed + if not source.has_template(tmpl, args.template_dir): + create(args) + name = args.name if name is None: randomid = ''.join(random.choice(string.lowercase) for i in range(10)) @@ -213,7 +225,7 @@ def gen_create_args(subparser): requires_connect(parser) requires_template_dir(parser) parser.add_argument("-f","--format", - default="qcow2", + default=default_format, help=_("format format for image")) parser.set_defaults(func=create) diff --git a/libvirt-sandbox/image/sources/DockerSource.py b/libvirt-sandbox/image/sources/DockerSource.py index 41df7a7..be9063d 100644 --- a/libvirt-sandbox/image/sources/DockerSource.py +++ b/libvirt-sandbox/image/sources/DockerSource.py @@ -59,6 +59,22 @@ class DockerSource(Source): if (major == 2 and sys.hexversion < py2_7_9_hexversion) or (major == 3 and sys.hexversion < py3_4_3_hexversion): sys.stderr.write(SSL_WARNING) + def was_downloaded(self, template, templatedir): + try: + self._get_image_list(template, templatedir) + return True + except Exception: + return False + + + def has_template(self, template, templatedir): + try: + configfile, diskfile = self._get_template_data(template, templatedir) + return os.path.exists(diskfile) + except Exception: + return False + + def download_template(self, template, templatedir): self._check_cert_validate() diff --git a/libvirt-sandbox/image/sources/Source.py b/libvirt-sandbox/image/sources/Source.py index 444baa3..e647448 100644 --- a/libvirt-sandbox/image/sources/Source.py +++ b/libvirt-sandbox/image/sources/Source.py @@ -35,6 +35,28 @@ class Source(): pass @abstractmethod + def was_downloaded(self, template, templatedir): + """ + :param template: libvirt_sandbox.template.Template object + :param templatedir: local directory path in which to store the template + + Check if a template has already been downloaded. + """ + pass + + + @abstractmethod + def has_template(self, template, templatedir): + """ + :param template: libvirt_sandbox.template.Template object + :param templatedir: local directory path in which to store the template + + Check if a template has already been created. + """ + pass + + + @abstractmethod def download_template(self, template, templatedir): """ :param template: libvirt_sandbox.template.Template object diff --git a/libvirt-sandbox/image/sources/VirtBuilderSource.py b/libvirt-sandbox/image/sources/VirtBuilderSource.py index 4a7e383..2dde715 100644 --- a/libvirt-sandbox/image/sources/VirtBuilderSource.py +++ b/libvirt-sandbox/image/sources/VirtBuilderSource.py @@ -31,6 +31,13 @@ class VirtBuilderSource(Source): # nobody can try to alter the folders structure later. return template.path[1:].replace('/', '_') + def was_downloaded(self, template, templatedir): + return True + + def has_template(self, template, templatedir): + imagepath = "%s/%s.qcow2" % (templatedir, template.path) + return os.path.exists(imagepath) + def download_template(self, template, templatedir): # We don't do anything here: virt-builder will do it for us in # the create action -- 2.1.4

Catch the exception in the main to avoid problems when auto-calling another function that fails. For example if run calls create and that one fails, run would have ignored the error. --- libvirt-sandbox/image/cli.py | 156 ++++++++++++++++++++----------------------- 1 file changed, 73 insertions(+), 83 deletions(-) diff --git a/libvirt-sandbox/image/cli.py b/libvirt-sandbox/image/cli.py index f4472d9..eb6bbb4 100755 --- a/libvirt-sandbox/image/cli.py +++ b/libvirt-sandbox/image/cli.py @@ -66,98 +66,85 @@ def info(msg): sys.stdout.write(msg) def download(args): - try: - tmpl = template.Template.from_uri(args.template) - source = tmpl.get_source_impl() - source.download_template(template=tmpl, - templatedir=args.template_dir) - except Exception,e: - print "Download Error %s" % str(e) + tmpl = template.Template.from_uri(args.template) + source = tmpl.get_source_impl() + source.download_template(template=tmpl, + templatedir=args.template_dir) def delete(args): - try: - tmpl = template.Template.from_uri(args.template) - source = tmpl.get_source_impl() - source.delete_template(template=tmpl, - templatedir=args.template_dir) - except Exception,e: - print "Delete Error %s" % str(e) + tmpl = template.Template.from_uri(args.template) + source = tmpl.get_source_impl() + source.delete_template(template=tmpl, + templatedir=args.template_dir) def create(args): - try: - tmpl = template.Template.from_uri(args.template) - source = tmpl.get_source_impl() + tmpl = template.Template.from_uri(args.template) + source = tmpl.get_source_impl() - if not source.was_downloaded(tmpl, args.template_dir): - download(args) + if not source.was_downloaded(tmpl, args.template_dir): + download(args) - fmt = default_format - if "format" in vars(args): - fmt = args.format + fmt = default_format + if "format" in vars(args): + fmt = args.format - source.create_template(template=tmpl, - templatedir=args.template_dir, - connect=args.connect, - format=fmt) - except Exception,e: - print "Create Error %s" % str(e) + source.create_template(template=tmpl, + templatedir=args.template_dir, + connect=args.connect, + format=fmt) def run(args): - try: - if args.connect is not None: - check_connect(args.connect) - tmpl = template.Template.from_uri(args.template) - source = tmpl.get_source_impl() - - # Create the template image if needed - if not source.has_template(tmpl, args.template_dir): - create(args) - - name = args.name - if name is None: - randomid = ''.join(random.choice(string.lowercase) for i in range(10)) - name = tmpl.path[1:] + ":" + randomid - - diskfile = source.get_disk(template=tmpl, - templatedir=args.template_dir, - imagedir=args.image_dir, - sandboxname=name) - - format = "qcow2" - commandToRun = source.get_command(tmpl, args.template_dir, args.args) - if len(commandToRun) == 0: - commandToRun = ["/bin/sh"] - cmd = ['virt-sandbox', '--name', name] - if args.connect is not None: - cmd.append("-c") - cmd.append(args.connect) - params = ['-m','host-image:/=%s,format=%s' %(diskfile,format)] - - networkArgs = args.network - if networkArgs is not None: - params.append('-N') - params.append(networkArgs) - - allEnvs = source.get_env(tmpl, args.template_dir) - envArgs = args.env - if envArgs is not None: - allEnvs = allEnvs + envArgs - for env in allEnvs: - envsplit = env.split("=") - envlen = len(envsplit) - if envlen == 2: - params.append("--env") - params.append(env) - else: - pass - - cmd = cmd + params + ['--'] + commandToRun - subprocess.call(cmd) - os.unlink(diskfile) - source.post_run(tmpl, args.template_dir, name) - - except Exception,e: - print "Run Error %s" % str(e) + if args.connect is not None: + check_connect(args.connect) + tmpl = template.Template.from_uri(args.template) + source = tmpl.get_source_impl() + + # Create the template image if needed + if not source.has_template(tmpl, args.template_dir): + create(args) + + name = args.name + if name is None: + randomid = ''.join(random.choice(string.lowercase) for i in range(10)) + name = tmpl.path[1:] + ":" + randomid + + diskfile = source.get_disk(template=tmpl, + templatedir=args.template_dir, + imagedir=args.image_dir, + sandboxname=name) + + format = "qcow2" + commandToRun = source.get_command(tmpl, args.template_dir, args.args) + if len(commandToRun) == 0: + commandToRun = ["/bin/sh"] + cmd = ['virt-sandbox', '--name', name] + if args.connect is not None: + cmd.append("-c") + cmd.append(args.connect) + params = ['-m','host-image:/=%s,format=%s' %(diskfile,format)] + + networkArgs = args.network + if networkArgs is not None: + params.append('-N') + params.append(networkArgs) + + allEnvs = source.get_env(tmpl, args.template_dir) + envArgs = args.env + if envArgs is not None: + allEnvs = allEnvs + envArgs + for env in allEnvs: + envsplit = env.split("=") + envlen = len(envsplit) + if envlen == 2: + params.append("--env") + params.append(env) + else: + pass + + cmd = cmd + params + ['--'] + commandToRun + subprocess.call(cmd) + os.unlink(diskfile) + source.post_run(tmpl, args.template_dir, name) def requires_template(parser): parser.add_argument("template", @@ -276,3 +263,6 @@ def main(): sys.stderr.write("%s: %s\n" % (sys.argv[0], e)) sys.stderr.flush() sys.exit(1) + except Exception, e: + print e.message + sys.exit(1) -- 2.1.4

Rather than letting the python exception hit the user, catch them and provide a more meaningful message if no or a bad scheme is provided in the URI. --- libvirt-sandbox/image/template.py | 24 +++++++++++++++--------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/libvirt-sandbox/image/template.py b/libvirt-sandbox/image/template.py index efdd845..58904a2 100644 --- a/libvirt-sandbox/image/template.py +++ b/libvirt-sandbox/image/template.py @@ -59,15 +59,21 @@ class Template(object): self.params = {} def get_source_impl(self): - p = re.compile("\W") - sourcename = "".join([i.capitalize() for i in p.split(self.source)]) - - mod = importlib.import_module( - "libvirt_sandbox.image.sources." + - sourcename + "Source") - classname = sourcename + "Source" - classimpl = getattr(mod, classname) - return classimpl() + if self.source == "": + raise Exception("Missing scheme in image URI") + + try: + p = re.compile("\W") + sourcename = "".join([i.capitalize() for i in p.split(self.source)]) + + mod = importlib.import_module( + "libvirt_sandbox.image.sources." + + sourcename + "Source") + classname = sourcename + "Source" + classimpl = getattr(mod, classname) + return classimpl() + except Exception: + raise Exception("Invalid source: '%s'" % self.source) def __repr__(self): if self.protocol is not None: -- 2.1.4