Conda package specification#
A conda package is an archive file that contains:
Metadata under the
info/directory.A collection of files that are installed directly into an install prefix.
There are currently two formats of archives that are supported:
Type |
Description |
.tar.bz2 |
The original format of conda packages. Is the default output of conda-build. |
.conda |
2nd Gen. This is a more compact and thus faster. Can be outputed from conda-build by setting output in |
The formats are identical across platforms and operating systems.
During the install process, all files are extracted into the
install prefix, with the exception of the ones in info/.
Installing a conda package into an environment is similar to
executing the following commands:
cd <environment prefix>
tar xjf some-package-1.0-0.tar.bz2
Only files, including symbolic links, are part of a conda package. Directories are not included. Directories are created and removed as needed, but you cannot create an empty directory from the tar archive directly.
Package metadata#
The info/ directory contains all metadata about a package.
Files in this location are not installed under the install
prefix. Although you are free to add any file to this directory,
conda only inspects the content of the files discussed below.
info/index.json#
This file contains basic information about the package, such as
name, version, build string, and dependencies. The content of this
file is stored in repodata.json, which is the repository
index file, hence the name index.json. The JSON object is a
dictionary containing the keys shown below. The filename of the
conda package is composed of the first 3 values, as in:
<name>-<version>-<build>.tar.bz2 or <name>-<version>-<build>.conda.
Key |
Type |
Description |
name |
string |
The lowercase name of the package. May contain the "-" character. |
version |
string |
The package version. May not contain "-". Conda acknowledges PEP 440. |
build |
string |
The build string. May not contain "-". Differentiates builds of packages with otherwise identical names and versions, such as:
|
build_number |
integer |
A non-negative integer representing the build number of the package. Unlike the build string, the Conda uses it to sort packages that have otherwise identical names and versions to determine the latest one. This is important because new builds that contain bug fixes for the way a package is built may be added to a repository. |
depends |
list of strings |
A list of dependency specifications, where each element is a string, as outlined in Package match specifications. |
arch |
string |
Optional. The architecture the package is built for. EXAMPLE: Conda currently does not use this key. |
platform |
string |
Optional. The OS that the package is built for. EXAMPLE: Conda currently does not use this key. Packages for a specific architecture and platform are usually distinguished by the repository subdirectory that contains them. |
info/files#
Lists all files that are part of the package itself, 1 per line.
All of these files need to get linked into the environment. Any
files in the package that are not listed in this file are not
linked when the package is installed. The directory delimiter for
the files in info/files should always be "/", even on
Windows. This matches the directory delimiter used in the
tarball.
info/has_prefix#
Optional file. Lists all files that contain a hard-coded build prefix or placeholder prefix, which needs to be replaced by the install prefix at installation time.
Note
Due to the way the binary replacement works, the placeholder prefix must be longer than the install prefix.
Each line of this file should be either a path, in which case it
is considered a text file with the default placeholder
/opt/anaconda1anaconda2anaconda3, or a space-separated list
of placeholder, mode, and path, where:
Placeholder is the build or placeholder prefix.
Mode is either
textorbinary.Path is the relative path of the file to be updated.
EXAMPLE: On Windows:
"Scripts/script1.py"
"C:\Users\username\anaconda\envs\_build" text "Scripts/script2.bat"
"C:/Users/username/anaconda/envs/_build" binary "Scripts/binary"
EXAMPLE: On macOS or Linux:
bin/script.sh
/Users/username/anaconda/envs/_build binary bin/binary
/Users/username/anaconda/envs/_build text share/text
Note
The directory delimiter for the relative path must always
be "/", even on Windows. The placeholder may contain either "\"
or "/" on Windows, but the replacement prefix will match the
delimiter used in the placeholder. The default placeholder
/opt/anaconda1anaconda2anaconda3 is an exception, being
replaced with the install prefix using the native path
delimiter. On Windows, the placeholder and path always appear
in quotes to support paths with spaces.
info/license.txt#
Optional file. The software license for the package.
info/no_link#
Optional file. Lists all files that cannot be linked---either soft-linked or hard-linked---into environments and are copied instead.
info/about.json#
Optional file. Contains the entries in the About section
of the meta.yaml file. The following keys are
added to info/about.json if present in the build recipe:
home.
dev_url.
doc_url.
license_url.
license.
summary.
description.
license_family.
info/recipe#
A directory containing the full contents of the build recipe.
meta.yaml.rendered#
The fully rendered build recipe. See conda render.
This directory is present only when the the include_recipe flag
is True in the Build section.
Link and unlink scripts#
You may optionally execute scripts before and after the link and unlink steps. For more information, see Adding pre-link, post-link, and pre-unlink scripts.
Repository structure and index#
A conda repository---or channel---is a directory tree, usually
served over HTTPS, which has platform subdirectories, each of
which contains conda packages and a repository index. The index
file repodata.json lists all conda packages in the platform
subdirectory. Use conda index to create such an index from
the conda packages within a directory. It is simple mapping of
the full conda package filename to the dictionary object in
info/index.json described in Adding pre-link, post-link, and pre-unlink scripts.
In the following example, a repository provides the conda package
misc-1.0-np17py27_0.tar.bz2 on 64-bit Linux and 32-bit
Windows:
<some path>/linux-64/repodata.json
repodata.json.bz2
misc-1.0-np17py27_0.tar.bz2
/win-32/repodata.json
repodata.json.bz2
misc-1.0-np17py27_0.tar.bz2
Note
Both conda packages have identical filenames and are distinguished only by the repository subdirectory that contains them.
Package match specifications#
This match specification is not the same as the syntax used at
the command line with conda install, such as
conda install python=3.4. Internally, conda translates the
command line syntax to the spec defined in this section.
EXAMPLE: python=3.4 is translated to python 3.4.*. conda search 'python=3.1' does NOT bring up Python 3.10, only Python 3.1.*.
Package dependencies are specified using a match specification. A match specification is a space-separated string of 1, 2, or 3 parts:
The first part is always the exact name of the package.
The second part refers to the version and may contain special characters. See table below.
The third part is always the exact build string. When there are three parts, the second part must be the exact version.
Symbol |
Meaning |
Example |
|---|---|---|
<, >, <=, >= |
Relational operators on versions, which are compared using PEP-440. |
|
==, and != |
Exact equality and not equalities. |
|
~= |
Compatibility Release |
|
| |
OR |
|
* |
Matches 0 or more characters in the version string. In terms of regular expressions, it is the same as |
|
, |
AND |
|
Hint
, has higher precedence than |, so >=1,<2|>3 means greater than or equal to 1 AND less than 2 or greater than 3, which matches 1, 1.3 and 3.0, but not 2.2.
Note
For package match specifications, pre-release versioning is also supported such that >1.0b4 will match 1.0b5 and 1.0rc1 but not 1.0b4 or 1.0a5.
Conda parses the version by splitting it into parts separated by |. If the part begins with <, >, =, or !, it is parsed as a relational operator. Otherwise, it is parsed as a version, possibly containing the "*" operator.
Remember that the version specification cannot contain spaces,
as spaces are used to delimit the package, version, and build
string in the whole match specification. python >= 2.7 is an
invalid match specification. However, "python >= 2.7" (with double or single quotes) is
matched as any version of a package named python>=2.7.
Examples of Package Specs#
The build string constraint "numpy=1.11.2=*nomkl*" matches the NumPy 1.11.2 packages without MKL, but not the normal MKL NumPy 1.11.2 packages.
The build string constraint "numpy=1.11.1|1.11.3=py36_0" matches NumPy 1.11.1 or 1.11.3 built for Python 3.6, but not any versions of NumPy built for Python 3.5 or Python 2.7.
The following are all valid match specifications for numpy-1.8.1-py27_0:
numpy
numpy 1.8*
numpy 1.8.1
numpy >=1.8
numpy ==1.8.1
numpy 1.8|1.8*
numpy >=1.8,<2
numpy >=1.8,<2|1.9
numpy 1.8.1 py27_0
numpy=1.8.1=py27_0
Command Line Match Spec Examples#
When using the command line, put double or single quotes around any package version specification that contains the space character or any of the following characters: <, >, *, or |.
Example |
Meaning |
|---|---|
|
The fuzzy constraint numpy=1.11 matches 1.11, 1.11.0, 1.11.1, 1.11.2, 1.11.18, and so on. |
|
The exact constraint numpy==1.11 matches 1.11, 1.11.0, 1.11.0.0, and so on. |
|
The OR constraint "numpy=1.11.1|1.11.3" matches with 1.11.1 or 1.11.3. |
|
Any numpy version 1.12.0a or greater. |
|
The AND constraint "numpy>=1.8,<2" matches with 1.8 and 1.9 but not 2.0. |