Environment configuration

---

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

pyproject.toml hatch.toml

[tool.hatch.envs.<ENV_NAME>]

[envs.<ENV_NAME>]

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:

pyproject.toml hatch.toml

[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.

Note

Environments do not inherit matrices.

Dependencies

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

pyproject.toml hatch.toml

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

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

Installation

Features

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

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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.

For example, in the following configuration:

pyproject.toml hatch.toml

[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.

pyproject.toml hatch.toml

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

Tip

Scripts inherit from parent environments just like options.

Commands

All commands are able to use any defined scripts.

Pre-install

You can run commands immediately before environments install your project.

pyproject.toml hatch.toml

[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.

pyproject.toml hatch.toml

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

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

Python version

The python option selects which version of Python to use:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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.

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.

Matrix

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

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[[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:

pyproject.toml hatch.toml

[[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

Note

The value of this variable sets the Python version.

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:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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:

pyproject.toml hatch.toml

[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.

pyproject.toml hatch.toml

[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.

pyproject.toml hatch.toml

[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.

pyproject.toml hatch.toml

[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-:

pyproject.toml hatch.toml

[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.

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:

pyproject.toml hatch.toml

[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"]

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Last update: December 29, 2021