Environment Variables

Reference to including remote environment variables

Overview

mirrord lets you run a local process in the context of remote environment i.e. environment variables present in the remote pod will be loaded into the local process.

For example, if you want your local process to access a remote database, the connection string configured in the remote pod's environment variable can be used by your local process.

How does it work?

mirrord - fileops

mirrord-layer sends a message to mirrord-agent requesting remote environment variables, which are then set before the local process starts.

Usage

To include/exclude environment variables selectively, use the --override-env-vars-include flag to include and --override-env-vars-exclude to exclude with environment variables specified in a semicolon separated list.

Note: These flags are mutually exclusive. For example, if one chooses to exclude using the --override-env-vars-exclude flag, then there is no need to use --override-env-vars-include="*" to include all other environment variables.

By default, all environment variables are included.

Example

If on our target pod, we have the environment variable ENV_VAR1 with the value remote-value and on our local machine we have ENV_VAR1 with value local-value, then Running the python interpreter with mirrord would look like this:

MIRRORD_AGENT_IMAGE=test MIRRORD_AGENT_RUST_LOG=trace RUST_LOG=debug target/debug/mirrord exec -c --target pod/py-serv-deployment-ff89b5974-x9tjx python3

Python 3.9.13 (v3.9.13:6de2ca5339, May 17 2022, 11:23:25)
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> print(os.environ['ENV_VAR1'])
remote-value

Logs

❯ MIRRORD_AGENT_IMAGE=test MIRRORD_AGENT_RUST_LOG=trace RUST_LOG=debug target/debug/mirrord exec -c --target pod/py-serv-deployment-ff89b5974-x9tjx python3
...
2022-07-01T17:18:33.744996Z DEBUG mirrord_layer: ClientMessage::GetEnvVarsRequest codec_result Ok(
    (),
)
2022-07-01T17:18:33.754270Z DEBUG mirrord_layer: DaemonMessage::GetEnvVarsResponse Ok(
    {
        "KUBERNETES_PORT": "tcp://10.96.0.1:443",
        "LANG": "C.UTF-8",
        "KUBERNETES_SERVICE_PORT": "443",
        "PY_SERV_PORT": "tcp://10.96.139.36:80",
        "KUBERNETES_PORT_443_TCP": "tcp://10.96.0.1:443",
        "PY_SERV_SERVICE_PORT": "80",
        "KUBERNETES_SERVICE_PORT_HTTPS": "443",
        "PYTHON_SETUPTOOLS_VERSION": "58.1.0",
        "PY_SERV_PORT_80_TCP_ADDR": "10.96.139.36",
        "PYTHON_GET_PIP_SHA256": "ba3ab8267d91fd41c58dbce08f76db99f747f716d85ce1865813842bb035524d",
        "ENV_VAR1": "remote-value",
        "KUBERNETES_SERVICE_HOST": "10.96.0.1",
        "KUBERNETES_PORT_443_TCP_PORT": "443",
        "HOSTNAME": "py-serv-deployment-ff89b5974-x9tjx",
        "KUBERNETES_PORT_443_TCP_ADDR": "10.96.0.1",
        "GPG_KEY": "E3FF2839C048B25C084DEBE9B26995E310250568",
        "PYTHON_GET_PIP_URL": "https://github.com/pypa/get-pip/raw/6ce3639da143c5d79b44f94b04080abf2531fd6e/public/get-pip.py",
        "PY_SERV_PORT_80_TCP": "tcp://10.96.139.36:80",
        "KUBERNETES_PORT_443_TCP_PROTO": "tcp",
        "PYTHON_VERSION": "3.9.13",
        "PY_SERV_PORT_80_TCP_PROTO": "tcp",
        "PY_SERV_PORT_80_TCP_PORT": "80",
        "PY_SERV_SERVICE_HOST": "10.96.139.36",
        "PYTHON_PIP_VERSION": "22.0.4",
    },
)!
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