Clojure library for programatically Compressing & Decompressing JAR files
(compress! source-jar & {:as options})
(decompress! source-jar & {:as options})
Why would you want to do this? Maybe you're bundling a bunch of JARs inside your uberjar and then extracting them and adding them to the classpath at runtime. Might as well shrink those JARs as small as we can
(compress! "/Users/cam/metabase/resources/modules/sparksql.metabase-driver.jar"
:blacklist "/Users/cam/metabase/uberjar-blacklist.txt"
:pack200 {:classes-to-skip ["org/apache/hadoop/hive/shims/Hadoop23Shims.class"]}
:compression :gz)
The first arg to compress!
is the source JAR. It can be either a
String filename, java.nio.files.Path
, or an InputStream
.
You can optionally include a list of files to exclude from the
destination JAR by specifiying :blacklist
. The blacklist can be
either a collection of filename strings, or a single string filename
containing a list of filenames separated by newlines; a typical way to
generate this file would be something like:
jar -tf target/uberjar/metabase.jar > uberjar-blacklist.txt
Whether to use Pack 200 to pack the JAR. Defaults to true
. You may
instead pass a map of pack 200 options. Currently, the only supported
option is classes-to-skip
; like :blacklist
, this may be either a
collection or the name of a file containing a list of classes to skip.
(Yes, Pack 200 is deprecated, but until we target only the version of Java where it is removed and above we will be able to continue to use it, which should be many years in the future. For example, if we compile against Java 8, there's no reason we can't include the Pack 200 classes as part of this library to support usage on Java 13 or whatever version removes those classes; only when we start compiling against Java 13 will it be time to retire things entirely.)
Whether to strip directories from the resulting JAR. Defaults to
true
. You should only set this to false
if you need to get a URI
to one of the directories in the JAR, e.g. via class.getResource()
or the like;
this isn't true of any Metabase drivers, which is why it is false
by
default.
In contrast, note that the Metabase uberjar itself needs to keep
directory entries because we iterate over entries under the modules
directory (via io/resource
).
Whether to strip Clojure and Java source files from the compressed JAR. Default: true
Compression method to use. Defaults to :xz
. Allowed options are
:xz
, :gz
(GZIP), or :none
. Note that JARs are already
compressed, so using :compression
without pack 200 is unlikely to
reduce the JAR size by more that a few percentage points.
Name of the String
destination file, or Path
, or OutputStream
,
to write the packed and compressed bytes to. Defaults to something
like <input-filename>.pack.xz
, with extensions based on the values
of the :pack200
and :compression
options. Note that if the input
isn't a String filename or Path, we can't come up with a default
output filename, and you'll have to specify :out
.
(decompress! "/Users/cam/metabase/resources/modules/sparksql.metabase-driver.jar.pack.xz")
Name of the (String) filename to decompress, or a Path
or InputStream
.
Whether this should be pack200-unpacked. Defaults to true
if the
input filename contains .pack
as the last or second-to-last
extension. Note that if input is not a filename (i.e., if input is an
InputStream
), we cannot determine the default value of this, and so you
must specify this option.
Compression algorithm to use to decompress input. By default, inferred
from the input filename; if input is an InputStream
, you must
specify this option manually.
It is probably possibly to look at the first few bytes and infer the algorithm that way instead; PRs welcome!
String or Path
Filename to write decompressed/unpacked results
bytes, or an OutputStream
. Defaults to the input filename without
.pack
and without .xz
/.gz
; if input is not a filename, you must
specify this option manually.
You can add support for additional compression algorithms by adding
implementations for metabase.jar-compression.algorithms
methods
compressed-input-stream
and compressed-output-stream
.
You can add support for more input and output types besides String
and Path
filenames and InputStream
/OutputStream
by adding
implementations for metabase.jar-compression.common
methods
->input-stream
and ->output-stream
.
Copyright © 2018 Metabase, Inc.
Distributed under the Eclipse Public License, same as Clojure.
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