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Check whether a Conda environment exists

Source: R/env_exists.R
env_exists.Rd

Checks whether an environment name is present in the environments managed by condathis.

Usage

env_exists(env_name = "condathis-env", method = "auto", verbose = "silent")

Arguments

env_name

Character string with the environment name. It must be a plain directory name that is valid on Linux, macOS and Windows:

  • Not empty, and not . or ...

  • Not starting with -, and not ending with ..

  • Without path separators, :, #, whitespace, control characters or <>"|?*.

  • Not a Windows device name, such as NUL or COM1 (see Environment names in create_env()).

Invalid values abort with class condathis_invalid_env_name. Functions that take only names reject an env_path() value with class condathis_env_path_read_only. run(), run_bin(), run_pipeline() and run_step() accept one.

method

Character string naming the backend to query. "auto" (the default) covers every registered backend, in getOption("condathis.backend_priority") order, also a backend that reports itself unavailable. Any name from list_registered_backend_names() queries only that backend. "micromamba" is built in. The name of a backend whose package condathis knows, such as "rattler" of the rattlerthis package, also queries only that backend. condathis loads that package. When it is not installed, the call aborts with class condathis_backend_not_installed. "native" is a deprecated alias for "micromamba" (warns once per session). Invalid values abort with class condathis_invalid_method.

verbose

Character string that controls the console output. One of:

  • "output": show the output of the command and the messages of condathis.

  • "silent": show nothing.

  • "cmd": show the command line.

  • "spinner": show only a spinner.

  • "full": show the command line, the output, and the backend's own log.

TRUE means "output" and FALSE means "silent". Every level except "silent" shows a spinner in interactive sessions. Invalid values abort with class condathis_invalid_verbose (see condathis-conditions). The default is shown in Usage.

The command line shown, the cmd of a result and the messages of condathis show the password and the token of a URL as *****. micromamba does the same (https://user:*****@host/channel, https://host/t/*****/channel). The command still gets them.

Value

TRUE when a queried backend reports the environment. FALSE when every queried backend reports it absent. When the query fails for the backend that method names, env_exists() aborts with class condathis_env_exists_failed (also condathis_backend_error). With method = "auto", env_exists() skips a backend whose query fails and warns with class condathis_backend_query_failed. It aborts only when every backend fails.

Details

env_exists() is a query: it never creates an environment. When env_name has no directory under a backend's data directory, as on a new data directory, env_exists() returns FALSE. It does not start or install micromamba. When no micromamba binary is installed, the micromamba backend reads the envs directory of its data directory and the package records in conda-meta/ instead. It never installs micromamba.

See also

condathis-conditions for every condition class.

Other environments: create_env(), env_path(), get_env_dir(), install_packages(), list_envs(), list_packages(), remove_env(), validate_env()

Examples

if (FALSE) { # \dontrun{
condathis::with_sandbox_dir({
  # A local channel shipped with condathis, with `polyglot`: a
  # dependency-free script that runs on Linux, macOS and Windows.
  channel <- system.file(
    "extdata", "polyglot-channel",
    package = "condathis"
  )

  # Create the environment
  condathis::create_env(
    "polyglot",
    env_name = "polyglot-env",
    channels = channel
  )

  # Check if the environment exists
  print(condathis::env_exists("polyglot-env"))
  #> [1] TRUE

  # Check for a non-existent environment
  condathis::env_exists("non-existent-env")
  #> [1] FALSE
})
} # }