hexagonit.recipe.download 1.2.0

1.2.0 (2008-01-19)

• Added the download-only option to allow downloading arbitrary files. [dokai]

1.1.0 (2007-10-14)

• Refactored the install method so recipe subclasses can override the base directory. For more info see calculate_base method on Recipe class. [hexsprite]

• Recipe is now a new-style Python class so recipe subclasses can use super() method to get some default behavior. [hexsprite]

1.0.1 (2007-08-14)

• For consistency with other similar recipes, the recipe now sets a location option which may be read by other sections to learn where the package was extracted. This is an alias for the destination option.

1.0.0

• First public release.

Supported options

The hexagonit.recipe.download recipe can be used to download and extract packages from the net. It supports the following options:

url

URL to the package that will be downloaded and extracted. The supported package formats are .tar.gz, .tar.bz2, and .zip. The value must be a full URL, e.g. http://python.org/ftp/python/2.4.4/Python-2.4.4.tgz.

strip-top-level-dir

Switch to remove the top level directory from the extracted archive. This will work only if the archive has exactly one top level directory. Accepted values are ‘true’ or ‘false’. Defaults to ‘false’.

ignore-existing

Switch to ignore existing files and/or directories. By default, the extraction process fails if there is existing files or directories matching the ones from the archive. Enabling this option will skip these files/directories from the archive. When this recipe is uninstalled the ignored files/directories will not be removed. Accepted values are ‘true’ or ‘false’. Defaults to ‘false’.

md5sum

MD5 checksum for the package file. If available the MD5 checksum of the downloaded package will be compared to this value and if the values do not match the execution of the recipe will fail.

destination

The location where the extracted contents of the package will be placed. If omitted, a directory will be created under the buildout['parts-directory'] with the name of the section using the recipe.

download-only

When set to ‘true’, the recipe downloads the file without trying to extract it. This is useful for downloading non-tarball files. The strip-top-level-dir option will be ignored if this option is enabled. Defaults to false.

Additionally, the recipe honors the download-directory option set in the [buildout] section and stores the downloaded files under it. If the value is not set a directory called downloads will be created in the root of the buildout and the download-directory option set accordingly.

The recipe will first check if there is a local copy of the package before downloading it from the net. Files can be shared among different buildouts by setting the download-directory to the same location.

Simple example

>>> import os.path
>>> testdata = join(os.path.dirname(__file__), 'testdata')
>>> server = start_server(testdata)

In the simplest form we can download a simple package and have it extracted in the parts directory.

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %s/package1-1.2.3-final.tar.gz
... """ % server)

Ok, let’s run the buildout:

>>> print system(buildout)
Installing package1.
package1: Creating download directory: /sample-buildout/downloads
package1: Extracting package to /sample-buildout/parts/package1

First of all, the recipe downloaded the package for us and placed it in the downloads directory.

>>> ls(sample_buildout, 'downloads')
- package1-1.2.3-final.tar.gz

Let’s take a look at the buildout parts directory now.

>>> ls(sample_buildout, 'parts')
d package1

The containing directory is named after our part name. Within this directory are the contents of the extracted package.

>>> ls(sample_buildout, 'parts', 'package1')
d package1-1.2.3-final

The package contained a single top level directory. Let’s peek what’s inside.

>>> ls(sample_buildout, 'parts', 'package1', 'package1-1.2.3-final')
- CHANGES.txt
- README.txt
d src

MD5 checksums

The downloaded package can be verified against an MD5 checksum. This will make it easier to spot problems if the file has been changed.

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... """ % server)

Ok, let’s rerun the buildout.

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /sample-buildout/parts/package1

You will notice that the MD5 checksum was correct. Also rerunning the buildout used the previously downloaded file from the downloads directory instead downloading it again from the net.

Controlling the extraction process

We can also extract the archive to any arbitrary location and have the top level directory be stripped, which is often a useful feature.

>>> tmpcontainer = tmpdir('otherplace')
>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... destination = %(dest)s
... strip-top-level-dir = true
... """ % dict(server=server, dest=tmpcontainer))

Rerunning the buildout now gives us

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /otherplace

Taking a look at the extracted contents we can also see that the top-level directory has been stripped.

>>> ls(tmpcontainer)
- CHANGES.txt
- README.txt
d src

Partial extraction over existing content

By default, the recipe will fail if the destination where the package will be extracted already contains files or directories also included in the package.

>>> container = tmpdir('existing')
>>> existingdir = mkdir(container, 'src')

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... destination = %(dest)s
... strip-top-level-dir = true
... """ % dict(server=server, dest=container))

Running the buildout now will fail because of the existing src directory in the destination.

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /existing
package1: Target /existing/src already exists. Either remove it or set ``ignore-existing = true`` in your buildout.cfg to ignore existing files and directories.
While:
  Installing package1.
Error: File or directory already exists.

Setting the ignore-existing option will allow the recipe to proceed.

>>> rmdir(container)
>>> container = tmpdir('existing')
>>> existingdir = mkdir(container, 'src')

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... destination = %(dest)s
... strip-top-level-dir = true
... ignore-existing = true
... """ % dict(server=server, dest=container))

>>> print system(buildout)
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /existing
package1: Ignoring existing target: /existing/src

>>> ls(container)
- CHANGES.txt
- README.txt
d src

Also note that when the recipe is uninstalled the ignored targets will not be removed as they are not part of the output of this recipe. We can verify this by running the buildout again with a different destination.

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... strip-top-level-dir = true
... ignore-existing = true
... """ % dict(server=server))

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /sample-buildout/parts/package1

Now when we look into the directory containing the previous buildout we can see that the src directory is still there but the rest of the files are gone.

>>> ls(container)
d src

Offline mode

If the buildout is run in offline mode the recipe will still work if the package is cached in the downloads directory. Otherwise the user will be informed that downloading the file is not possible in offline mode.

>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
... offline = true
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... strip-top-level-dir = true
... """ % dict(server=server))

Let’s verify that we do have a cached copy in our downloads directory.

>>> ls(sample_buildout, 'downloads')
- package1-1.2.3-final.tar.gz

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Using a cached copy from /sample-buildout/downloads/package1-1.2.3-final.tar.gz
package1: MD5 checksum OK
package1: Extracting package to /sample-buildout/parts/package1

When we remove the file from the filesystem the recipe will not work.

>>> remove(sample_buildout, 'downloads', 'package1-1.2.3-final.tar.gz')
>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package1
... offline = true
...
... [package1]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... """ % dict(server=server))

>>> print system(buildout)
Uninstalling package1.
Installing package1.
package1: Unable to download file in offline mode. Either run the buildout in online mode or place a copy of the file in /sample-buildout/downloads/package1-1.2.3-final.tar.gz
While:
  Installing package1.
Error: Download error

Downloading arbitrary files

We can download any file when setting the download-only option to true. This will simply place the file in the destination directory.

>>> downloads = tmpdir('downloads')
>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = package
...
... [package]
... recipe = hexagonit.recipe.download
... url = %(server)s/package1-1.2.3-final.tar.gz
... md5sum = 821ecd681758d3fc03dcf76d3de00412
... destination = %(dest)s
... download-only = true
... """ % dict(server=server, dest=downloads))

>>> print system(buildout)
Installing package.
package: MD5 checksum OK

Looking into the destination directory we can see that the file was downloaded but not extracted. Using the download-only option will work for any file regardless of the type.

>>> ls(downloads)
-  package1-1.2.3-final.tar.gz