Environment configuration¶

All environments are defined as sections within the tool.hatch.envs table.

[tool.hatch.envs.<ENV_NAME>]

[envs.<ENV_NAME>]

The storage location for environments is completely configurable.

Unless an environment is explicitly selected on the command line, the default environment will be used. The type of this environment defaults to virtual.

Inheritance¶

All environments inherit from the environment defined by its template option, which defaults to default.

So for the following configuration:

[tool.hatch.envs.foo]
type = "baz"
skip-install = true

[tool.hatch.envs.bar]
template = "foo"
skip-install = false

[envs.foo]
type = "baz"
skip-install = true

[envs.bar]
template = "foo"
skip-install = false

the environment bar will be of type baz with skip-install set to false.

Self-referential environments¶

You can disable inheritance by setting template to the environment's own name:

[tool.hatch.envs.foo]
template = "foo"

[envs.foo]
template = "foo"

Detached environments¶

A common use case is standalone environments that do not require inheritance nor the installation of the project, such as for linting or sometimes building documentation. Enabling the detached option will make the environment self-referential and will skip project installation:

[tool.hatch.envs.lint]
detached = true

[envs.lint]
detached = true

Dependencies¶

You can install dependencies in addition to the ones defined by your project's metadata. Entries support context formatting.

[tool.hatch.envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
  "pytest-mock",
]

[envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
  "pytest-mock",
]

If you define environments with dependencies that only slightly differ from their inherited environments, you can use the extra-dependencies option to avoid redeclaring the dependencies option:

[tool.hatch.envs.default]
dependencies = [
  "foo",
  "bar",
]

[tool.hatch.envs.experimental]
extra-dependencies = [
  "baz",
]

[envs.default]
dependencies = [
  "foo",
  "bar",
]

[envs.experimental]
extra-dependencies = [
  "baz",
]

Installation¶

Features¶

If your project defines optional dependencies, you can select which groups to install using the features option:

[tool.hatch.envs.nightly]
features = [
  "server",
  "grpc",
]

[envs.nightly]
features = [
  "server",
  "grpc",
]

Dev mode¶

By default, environments will always reflect the current state of your project on disk. Set dev-mode to false to disable this behavior:

[tool.hatch.envs.static]
dev-mode = false

[envs.static]
dev-mode = false

Skip install¶

By default, environments will install your project during creation. To ignore this step, set skip-install to true:

[tool.hatch.envs.lint]
skip-install = true

[envs.lint]
skip-install = true

Environment variables¶

Defined¶

You can define environment variables with the env-vars option:

[tool.hatch.envs.docs]
dependencies = [
  "mkdocs"
]
[tool.hatch.envs.docs.env-vars]
SOURCE_DATE_EPOCH = "1580601600"

[envs.docs]
dependencies = [
  "mkdocs"
]
[envs.docs.env-vars]
SOURCE_DATE_EPOCH = "1580601600"

Filters¶

By default, environments will have access to all environment variables. You can filter with wildcard patterns using the env-include/env-exclude options:

[tool.hatch.envs.<ENV_NAME>]
env-include = [
  "FOO*",
]
env-exclude = [
  "BAR",
]

[envs.<ENV_NAME>]
env-include = [
  "FOO*",
]
env-exclude = [
  "BAR",
]

Exclusion patterns take precedence but will never affect defined environment variables.

Scripts¶

You can define named scripts that may be executed or referenced at the beginning of other scripts. Context formatting is supported.

For example, in the following configuration:

[tool.hatch.envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
  "pytest-mock",
]
[tool.hatch.envs.test.scripts]
run-coverage = "pytest --cov-config=pyproject.toml --cov=pkg --cov=tests"
run = "run-coverage --no-cov"

[envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
  "pytest-mock",
]
[envs.test.scripts]
run-coverage = "pytest --cov-config=pyproject.toml --cov=pkg --cov=tests"
run = "run-coverage --no-cov"

the run script would be expanded to:

pytest --cov-config=pyproject.toml --cov=pkg --cov=tests --no-cov

Scripts can also be defined as an array of strings.

[tool.hatch.envs.style]
detached = true
dependencies = [
  "flake8",
  "black",
  "isort",
]
[tool.hatch.envs.style.scripts]
check = [
  "flake8 .",
  "black --check --diff .",
  "isort --check-only --diff .",
]
fmt = [
  "isort .",
  "black .",
  "check",
]

[envs.style]
detached = true
dependencies = [
  "flake8",
  "black",
  "isort",
]
[envs.style.scripts]
check = [
  "flake8 .",
  "black --check --diff .",
  "isort --check-only --diff .",
]
fmt = [
  "isort .",
  "black .",
  "check",
]

Similar to make, you can ignore the exit code of commands that start with - (a hyphen). For example, the script error defined by the following configuration would halt after the second command with 3 as the exit code:

[tool.hatch.envs.test.scripts]
error = [
  "- exit 1",
  "exit 3",
  "exit 0",
]

[envs.test.scripts]
error = [
  "- exit 1",
  "exit 3",
  "exit 0",
]

Commands¶

All commands are able to use any defined scripts. Also like scripts, context formatting is supported and the exit code of commands that start with a hyphen will be ignored.

Pre-install¶

You can run commands immediately before environments install your project.

[tool.hatch.envs.<ENV_NAME>]
pre-install-commands = [
  "...",
]

[envs.<ENV_NAME>]
pre-install-commands = [
  "...",
]

Post-install¶

You can run commands immediately after environments install your project.

[tool.hatch.envs.<ENV_NAME>]
post-install-commands = [
  "...",
]

[envs.<ENV_NAME>]
post-install-commands = [
  "...",
]

Python version¶

The python option specifies which version of Python to use, or an absolute path to a Python interpreter:

[tool.hatch.envs.<ENV_NAME>]
python = "3.10"

[envs.<ENV_NAME>]
python = "3.10"

All environment types should respect this option.

Supported platforms¶

The platforms option indicates the operating systems with which the environment is compatible:

[tool.hatch.envs.<ENV_NAME>]
platforms = ["linux", "windows", "macos"]

[envs.<ENV_NAME>]
platforms = ["linux", "windows", "macos"]

The following platforms are supported:

• linux
• windows
• macos

If unspecified, the environment is assumed to be compatible with all platforms.

Description¶

The description option is purely informational and is displayed in the output of the env show command:

[tool.hatch.envs.<ENV_NAME>]
description = """
Lorem ipsum ...
"""

[envs.<ENV_NAME>]
description = """
Lorem ipsum ...
"""

Type¶

An environment's type determines which environment plugin will be used for management. The only built-in environment type is virtual, which uses virtual Python environments.

Context formatting¶

All environments support the following extra context formatting fields:

Matrix¶

Environments can define a series of matrices with the matrix option:

[tool.hatch.envs.test]
dependencies = [
  "pytest"
]

[[tool.hatch.envs.test.matrix]]
python = ["27", "38"]
version = ["42", "3.14"]

[[tool.hatch.envs.test.matrix]]
python = ["38", "39"]
version = ["9000"]
feature = ["foo", "bar"]

[envs.test]
dependencies = [
  "pytest"
]

[[envs.test.matrix]]
python = ["27", "38"]
version = ["42", "3.14"]

[[envs.test.matrix]]
python = ["38", "39"]
version = ["9000"]
feature = ["foo", "bar"]

Doing so will result in the product of each variable combination being its own environment.

Naming¶

The name of the generated environments will be the variable values of each combination separated by hyphens, altogether prefixed by <ENV_NAME>.. For example, the following configuration:

[[tool.hatch.envs.test.matrix]]
version = ["42"]
feature = ["foo", "bar"]

[[envs.test.matrix]]
version = ["42"]
feature = ["foo", "bar"]

would indicate the following unique environments:

test.42-foo
test.42-bar

The two exceptions to this format are described below.

Python variables¶

If the variables py or python are specified, then they will rank first in the product result and will be prefixed by py if the value is not. For example, the following configuration:

[[tool.hatch.envs.test.matrix]]
version = ["42"]
python = ["39", "pypy3"]

[[envs.test.matrix]]
version = ["42"]
python = ["39", "pypy3"]

would generate the following environments:

test.py39-42
test.pypy3-42

Name formatting¶

You can set the matrix-name-format option to modify how each variable part is formatted which recognizes the placeholders {variable} and {value}. For example, the following configuration:

[tool.hatch.envs.test]
matrix-name-format = "{variable}_{value}"

[[tool.hatch.envs.test.matrix]]
version = ["42"]
feature = ["foo", "bar"]

[envs.test]
matrix-name-format = "{variable}_{value}"

[[envs.test.matrix]]
version = ["42"]
feature = ["foo", "bar"]

would produce the following environments:

test.version_42-feature_foo
test.version_42-feature_bar

By default this option is set to {value}.

Default environment¶

If the default environment defines matrices, then the generated names will not be prefixed by the environment name. This can be useful for projects that only need a single series of matrices without any standalone environments.

Selection¶

Rather than selecting a single generated environment, you can select the root environment to target all of them. For example, if you have the following configuration:

[tool.hatch.envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
]

[tool.hatch.envs.test.scripts]
cov = 'pytest --cov-report=term-missing --cov-config=pyproject.toml --cov=pkg --cov=tests'

[[tool.hatch.envs.test.matrix]]
python = ["27", "38"]
version = ["42", "3.14"]

[envs.test]
dependencies = [
  "coverage[toml]",
  "pytest",
  "pytest-cov",
]

[envs.test.scripts]
cov = 'pytest --cov-report=term-missing --cov-config=pyproject.toml --cov=pkg --cov=tests'

[[envs.test.matrix]]
python = ["27", "38"]
version = ["42", "3.14"]

you could then run your tests consecutively in all 4 environments with:

hatch run test:cov

Option overrides¶

You can modify options based on the conditions of different sources like matrix variables with the overrides table, using dotted key syntax for each declaration:

[tool.hatch.envs.<ENV_NAME>.overrides]
<SOURCE>.<CONDITION>.<OPTION> = <VALUE>

[envs.<ENV_NAME>.overrides]
<SOURCE>.<CONDITION>.<OPTION> = <VALUE>

The type of the selected option determines the types of values.

Platform overrides¶

Options can be modified based on the current platform using the platform source.

[tool.hatch.envs.test.overrides]
platform.windows.scripts = [
  'run=pytest -m "not io_uring"',
]

[envs.test.overrides]
platform.windows.scripts = [
  'run=pytest -m "not io_uring"',
]

The following platforms are supported:

• linux
• windows
• macos

Environment variable overrides¶

Environment variables can modify options using the env source.

[tool.hatch.envs.test.overrides]
env.GITHUB_ACTIONS.dev-mode = { value = false, if = ["true"] }

[envs.test.overrides]
env.GITHUB_ACTIONS.dev-mode = { value = false, if = ["true"] }

Matrix variable overrides¶

The matrix variables used to generate each environment can be used to modify options within using the matrix source.

[tool.hatch.envs.test.overrides]
matrix.version.env-vars = "PRODUCT_VERSION"
matrix.auth.features = [
  { value = "oauth", if = ["oauth2"] },
  { value = "kerberos", if = ["krb5"] },
]

[[tool.hatch.envs.test.matrix]]
python = ["27", "38"]
version = ["legacy", "latest"]
auth = ["oauth2", "krb5", "noauth"]

[envs.test.overrides]
matrix.version.env-vars = "PRODUCT_VERSION"
matrix.auth.features = [
  { value = "oauth", if = ["oauth2"] },
  { value = "kerberos", if = ["kerberos"] },
]

[[envs.test.matrix]]
python = ["27", "38"]
version = ["legacy", "latest"]
auth = ["oauth2", "kerberos", "noauth"]

Types¶

• Literal types like strings for the Python version or booleans for skipping installation can be set using the value itself, an inline table, or an array. For example:

  pyproject.toml hatch.toml

  [tool.hatch.envs.test.overrides]
  matrix.foo.python = "310"
  matrix.bar.skip-install = { value = true, if = ["..."] }
  env.CI.dev-mode = [
    { value = false, if = ["..."] },
    true,
  ]
  

  [envs.test.overrides]
  matrix.foo.python = "310"
  matrix.bar.skip-install = { value = true, if = ["..."] }
  env.CI.dev-mode = [
    { value = false, if = ["..."] },
    true,
  ]
  

  For arrays, the first allowed value will be used.

• Array types like dependencies or commands can be appended to using an array of strings or inline tables. For example:

  pyproject.toml hatch.toml

  [tool.hatch.envs.test.overrides]
  matrix.foo.dependencies = [
    "httpx",
    { value = "cryptography" },
  ]
  

  [envs.test.overrides]
  matrix.foo.dependencies = [
    "httpx",
    { value = "cryptography" },
  ]
  

• Mapping types like environment variables or scripts can have keys set using a string, or an array of strings or inline tables. For example:

  pyproject.toml hatch.toml

  [tool.hatch.envs.test.overrides]
  matrix.foo.env-vars = "KEY=VALUE"
  matrix.bar.env-vars = [
    "KEY1=VALUE1",
    { key = "KEY2", value = "VALUE2" },
  ]
  

  [envs.test.overrides]
  matrix.foo.env-vars = "KEY=VALUE"
  matrix.bar.env-vars = [
    "KEY1=VALUE1",
    { key = "KEY2", value = "VALUE2" },
  ]
  

  If the value is missing (no = for strings, no value key for inline tables), then the value will be set to the value of the source condition.

Overwriting¶

Rather than supplementing the values within mapping types or array types, you can overwrite the option as a whole by prefixing the name with set-:

[tool.hatch.envs.test.overrides]
matrix.foo.set-platforms = ["macos", "linux"]

[envs.test.overrides]
matrix.foo.set-platforms = ["macos", "linux"]

When overwriting entire options or keys within mappings, override sources are applied in the following order:

1. platform
2. environment variables
3. matrix variables

Conditions¶

You may specify certain extra keys for any inline table that will determine whether or not to apply that entry. These modifiers may be combined with others and any negative evaluation will immediately cause the entry to be skipped.

Allowed values¶

The if key represents the allowed values for that condition. If the value of the condition is not listed, then that entry will not be applied:

[tool.hatch.envs.test.overrides]
matrix.version.python = { value = "pypy", if = ["3.14"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[tool.hatch.envs.test.matrix]]
version = ["42", "3.14"]

[envs.test.overrides]
matrix.version.python = { value = "pypy", if = ["3.14"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[envs.test.matrix]]
version = ["42", "3.14"]

Specific platforms¶

The platform key represents the desired platforms. If the current platform is not listed, then that entry will not be applied:

[tool.hatch.envs.test.overrides]
env.EXPERIMENTAL.python = { value = "pypy", if = ["1"], platform = ["macos"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"], platform = ["linux"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[tool.hatch.envs.test.matrix]]
version = ["42", "3.14"]

[envs.test.overrides]
env.EXPERIMENTAL.python = { value = "pypy", if = ["1"], platform = ["macos"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"], platform = ["linux"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[envs.test.matrix]]
version = ["42", "3.14"]

Required environment variables¶

The env key represents the required environment variables. If any of the listed environment variables are not set or the defined value does not match, then that entry will not be applied:

[tool.hatch.envs.test.overrides]
platform.windows.python = { value = "pypy", env = ["EXPERIMENTAL"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"], env = ["FOO", "BAR=BAZ"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[tool.hatch.envs.test.matrix]]
version = ["42", "3.14"]

[envs.test.overrides]
platform.windows.python = { value = "pypy", env = ["EXPERIMENTAL"] }
matrix.version.env-vars = [
  { key = "KEY1", value = "VALUE1", if = ["42"], env = ["FOO", "BAR=BAZ"] },
  { key = "KEY2", value = "VALUE2", if = ["3.14"] },
]

[[envs.test.matrix]]
version = ["42", "3.14"]