Conda package specification¶
A conda package is a bzipped tar archive—.tar.bz2—that contains:
- Metadata under the
- A collection of files that are installed directly into an install prefix.
The format is 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
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.
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.
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||string||The lowercase name of the package. May contain the “-” character.|
|version||string||The package version. May not contain “-“. Conda acknowledges PEP 440.|
The build string. May not contain “-“. Differentiates builds of packages with otherwise identical names and versions, such as:
A non-negative integer representing the build number of the package.
Unlike the build string, the build_number is inspected by conda. 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 to 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.|
Optional. The architecture the package is built for.
Conda currently does not use this key.
Optional. The OS that the package is built for.
Conda currently does not use this key. Packages for a specific architecture and platform are usually distinguished by the repository subdirectory that contains them—see Repository structure and index.
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
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
- 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.
Optional file. The software license for the package.
Optional file. Contains the entries in the About section
meta.yaml file. The following keys are
info/about.json if present in the build recipe:
A directory containing the full contents of the build recipe.
A conda repository—or channel—is a directory tree, usually
served over HTTPS, which has platform subdirectories, each of
which contain conda packages and a repository index. The index
repodata.json lists all conda packages in the platform
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 add-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
<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.
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*.
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:
| means OR.
1.0|1.2matches version 1.0 or 1.2
* matches 0 or more characters in the version string. In terms of regular expressions, it is the same as
EXAMPLE: 1.0|1.4* matches 1.0, 1.4 and 1.4.1b2, but not 1.2.
<, >, <=, >=, == and != are relational operators on versions, which are compared using PEP-440. For example,
1.0, but not
!=are exact equality.
Pre-release versioning is also supported such that
EXAMPLE: <=1.0 matches 0.9, 0.9.1, and 1.0, but not 1.0.1.
, means AND.
EXAMPLE: >=2,<3 matches all packages in the 2 series. 2.0, 2.1 and 2.9 all match, but 3.0 and 1.0 do not.
, 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.
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.
The third part is always the exact build string. When there are 3 parts, the second part must be the exact version.
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. Furthermore,
matched as any version of a package named
When using the command line, put double quotes around any package version specification that contains the space character or any of the following characters: <, >, * or |.
conda install numpy=1.11 conda install numpy==1.11 conda install "numpy>1.11" conda install "numpy=1.11.1|1.11.3" conda install "numpy>=1.8,<2"
The OR constraint “numpy=1.11.1|1.11.3” matches with 1.11.1 or 1.11.3.
The AND constraint “numpy>=1.8,<2” matches with 1.8 and 1.9 but not 2.0.
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, 188.8.131.52 and so on.
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 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