NAME

       envassert - Ensure that the environment variables match what you need, or abort.

VERSION

       version 0.010

SYNOPSIS

       envassert [options]

       Options:
           --help
           --man
           --version
           --break-at-error
           --env-description

DESCRIPTION

       envassert checks that your runtime environment, as defined with environment variables,
       matches with what you want.

       You can define your required environment in a file.  Default file is .envassert but you
       can use any file.

       It is advantageous to use envassert for examnple when running a container. If you check
       your environment for missing or wrongly defined environment variables at the beginning of
       the container run, your container will fail sooner instead of in a later point in
       execution when the variables are needed.

   Errors
       There are three kinds of errors:

       ENV_ASSERT_MISSING_FROM_ENVIRONMENT
               "Variable <var_name> is missing from environment"

       ENV_ASSERT_INVALID_CONTENT_IN_VARIABLE
               "Variable <var_name> has invalid content"

       ENV_ASSERT_MISSING_FROM_DEFINITION
               "Variable <var_name> is missing from description"

               This error will only be reported if you have set the special option exact. See
               below.

   Environment Description Language
       Environment is described in file .envdesc.  Environment description file is a Unix shell
       compatible file, similar to a .env file.

       .envdesc Format

       In .envdesc file there is only environment variables, comments or empty rows.  Example:

           # Required env
           ## envassert (opts: exact=1)
           FILENAME=^[[:word:]]{1,}$

       Env var name is followed by a regular expression. The regexp is an extended Perl regular
       expression without quotation marks.  One env var and its descriptive regexp use one row.

       A comment begins at the beginning of the row and uses the whole row.  It start with '#'
       character.

       Two comment characters and the word envassert at the beginning of the row mean this is an
       envassert meta command.  You can specify different environment related options with these
       commands.

       Supported options:

       exact   The option exact means that all allowed env variables are described in this file.
               Any unknown env var causes an error when verifying.

   CLI interface without dependencies
       The envassert command is also available as self contained executable.  You can download it
       and run it as it is without additional installation of CPAN packages.  Of course, you
       still need Perl, but Perl comes with any normal Linux installation.

       This can be convenient if you want to, for instance, include envassert in a docker
       container build.

           curl -LSs -o envassert https://raw.githubusercontent.com/mikkoi/env-assert/main/envassert.self-contained
           chmod +x ./envassert

OPTIONS

       --help  Print a brief help message and exits.

       --man   Prints the manual page and exits.

       --version
               Prints the version and exits.

       -b, --break-at-first-error
               Break checking at the first error and report back.  Default: false

       -e, --env-description
               Path to file which has the environment description.  Default: .envdesc

       -x, --exact
               Fail check if environment contains variables not defined in environment descript.
               This option will override the equivalent option in .envdesc file.  Default: false

EXAMPLES

           $ envassert
           Environment Assert: ERRORS:
               variables:
                   FIRST_VAR: Variable FIRST_VAR is missing from environment
                   FOURTH_VAR: Variable FOURTH_VAR is missing from environment

DEPENDENCIES

       No external dependencies outside Perl's standard distribution.

AUTHOR

       Mikko Koivunalho <mikkoi@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2023 by Mikko Koivunalho.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.