## The `password` flow

Now let's go back a bit and understand what is all that.

The `password` "flow" is one of the ways ("flows") defined in OAuth2, to handle security and authentication.

OAuth2 was designed so that the backend or API could be independent of the server that authenticates the user.

But in this case, the same **FastAPI** application will handle the API and the authentication.

There's a small detail about names to keep in mind. 💡

The word "**server**" is commonly used to refer to both the remote/cloud computer (the physical or virtual machine) and also the program that is running on that machine (e.g. Uvicorn).

Just keep in mind that when you read "server" in general, it could refer to one of those two things.

// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

fi

if [ -z "${SHA}" ]; then
  fail "Unable to retrieve the commit SHA of istio/api from go.mod file. Not updating the CRD file. Please make sure istio/api exists in the Go module.";
fi

git clone --filter=tree:0 "https://${REPO}" "${API_TMP}" && cd "${API_TMP}"
git checkout "${SHA}"
if [ ! -f "${API_TMP}/kubernetes/customresourcedefinitions.gen.yaml" ]; then

FESS_ENV_FILE="${packaging.env.file}"
if [ -f "$FESS_ENV_FILE" ]; then
    . "$FESS_ENV_FILE"
fi

IS_UPGRADE=false

case "$1" in

    # Debian ####################################################
    configure)

        # If $1=configure and $2 is set, this is an upgrade
        if [ -n $2 ]; then
            IS_UPGRADE=true
        fi
    ;;
    abort-upgrade|abort-remove|abort-deconfigure)

#
# The original version of this file is located in the https://github.com/istio/common-files repo.
# If you're looking at this file in a different repo and want to make a change, please go to the
# common-files repo, make the change there and check it in. Then come back to this repo and run
# "make update-common".

# Copyright Istio Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");

#
# The original version of this file is located in the https://github.com/istio/common-files repo.
# If you're looking at this file in a different repo and want to make a change, please go to the
# common-files repo, make the change there and check it in. Then come back to this repo and run
# "make update-common".

# Copyright Istio Authors
#
#   Licensed under the Apache License, Version 2.0 (the "License");

/*
 * Copyright 2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright 2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright 2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,