#!/bin/sh
# script/example-app: build the image, and on it the example app in
# deploy/example-app, then run the app's container, with rproxy in it, and
# discriminator in a container of its own with a volume for the state files. It
# checks:
#   - that the health checks pass;
#   - that a request is served through rproxy, and a second one in a minute
#     bans the client;
#   - that a probe for /.env bans another client, which its next request bans
#     for good;
#   - that only discriminator's container changes the state directory's owner;
#   - that the app still answers through rproxy with discriminator stopped, and
#     that once discriminator has started again, bans apply again;
#   - that `sv stop` stops rproxy in order, and `docker stop` stops each
#     container without having to kill it;
#   - that a new discriminator container on the same volume still refuses the banned
#     client;
#   - that a discriminator container with its state files on a new volume mounted at
#     the directory SWW_WAF_STATE_DIR_FILE names becomes healthy;
#   - that one whose SWW_WAF_STATE_DIR does not exist logs discriminator's message
#     about it.
# discriminator runs with SWW_WAF_LOOKUP_SOURCE=off, so that no address is sent to
# GeoJS. The containers, the network, the volumes and both images are removed
# however the script ends. Building the app needs network access, for nixpkgs'
# binary cache. script/check does not run this.
set -eu

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"

# Named after this run, so that runs in other clones on the same host
# never touch each other's.
NAME="$("$SCRIPT_DIR/projectname")-example-$$"
IMAGE="$NAME-base"
APP_IMAGE="$NAME-app"
NETWORK="$NAME"
APP="$NAME-app-container"
DISCRIMINATOR="$NAME-discriminator"
VOLUME="$NAME-state"
# The volumes of the container whose state directory SWW_WAF_STATE_DIR_FILE
# names: its state files, and the file that names their directory.
MOVED_VOLUME="$NAME-moved-state"
SETTINGS_VOLUME="$NAME-settings"

cleanup() {
    docker rm --force "$APP" "$DISCRIMINATOR" >/dev/null 2>&1 || true
    docker network rm "$NETWORK" >/dev/null 2>&1 || true
    docker volume rm --force "$VOLUME" "$MOVED_VOLUME" "$SETTINGS_VOLUME" \
        >/dev/null 2>&1 || true
    docker rmi --force "$APP_IMAGE" "$IMAGE" >/dev/null 2>&1 || true
}

fail() {
    echo "example-app: $*; the app container's output:" >&2
    docker logs "$APP" >&2 || true
    echo "example-app: discriminator's output:" >&2
    docker logs "$DISCRIMINATOR" >&2 || true
    exit 1
}

# wait_for <what fails> <command>...: run the command every second until
# it succeeds, for at most a minute.
wait_for() {
    failure="$1"
    shift
    tries=0
    until "$@"; do
        tries=$((tries + 1))
        [ "$tries" -lt 60 ] || fail "$failure"
        sleep 1
    done
}

# healthy <container>: docker says the container's health check passes.
healthy() {
    status="$(docker inspect --format '{{.State.Health.Status}}' "$1")"
    [ "$status" = healthy ]
}

# logged <container> <text>...: a line of the container's output holds every
# text, in any order.
logged() {
    lines="$(docker logs "$1" 2>&1)"
    shift
    for text in "$@"; do
        lines="$(printf '%s\n' "$lines" | grep -F "$text")" || return 1
    done
}

# start_discriminator: run discriminator from the image, with the state files on the
# volume, a rate limit of one request a minute and no client looked up, and wait
# until it is healthy.
start_discriminator() {
    docker run --detach --name "$DISCRIMINATOR" --network "$NETWORK" \
        --volume "$VOLUME:/var/lib/sww" \
        --env SWW_COMMAND=discriminator \
        --env SWW_WAF_RATE_LIMIT_PER_MINUTE=1 \
        --env SWW_WAF_LOOKUP_SOURCE=off \
        "$IMAGE" >/dev/null
    wait_for "discriminator's health check did not pass" healthy "$DISCRIMINATOR"
}

# start_app: run the app's container, with rproxy in it, and wait until it is
# healthy.
start_app() {
    docker run --detach --name "$APP" --network "$NETWORK" --publish 127.0.0.1::8080 \
        --env SWW_RPROXY_WAF_BACKEND="http://$DISCRIMINATOR:8080" \
        "$APP_IMAGE" >/dev/null
    wait_for "the app's health check did not pass" healthy "$APP"
    address="$(docker port "$APP" 8080/tcp)"
}

# start_moved_discriminator: run discriminator with the state files on a new volume at
# /srv/state, which SWW_WAF_STATE_DIR_FILE names in a file only the sww
# user can read, as under "Settings given as files" in docs/settings.md, and
# wait until it is healthy. discriminator can write the new volume only once the run
# script has given it to that user.
start_moved_discriminator() {
    docker volume create "$MOVED_VOLUME" >/dev/null
    docker volume create "$SETTINGS_VOLUME" >/dev/null
    docker run --rm --volume "$SETTINGS_VOLUME:/settings" \
        --entrypoint bash "$IMAGE" -c 'echo /srv/state > /settings/state-dir &&
            chown sww:sww /settings/state-dir &&
            chmod 0400 /settings/state-dir'
    docker run --detach --name "$DISCRIMINATOR" --network "$NETWORK" \
        --volume "$MOVED_VOLUME:/srv/state" \
        --volume "$SETTINGS_VOLUME:/etc/sww/settings:ro" \
        --env SWW_COMMAND=discriminator \
        --env SWW_WAF_STATE_DIR_FILE=/etc/sww/settings/state-dir \
        --env SWW_WAF_LOOKUP_SOURCE=off \
        "$IMAGE" >/dev/null
    wait_for "discriminator's health check did not pass" healthy "$DISCRIMINATOR"
}

# status_from <client> <path>: print the status a request for path from client,
# as X-Forwarded-For names it, gets. rproxy believes the header from docker's
# gateway, a private address.
status_from() {
    curl --silent --output /dev/null --write-out '%{http_code}' \
        --max-time 10 --header "X-Forwarded-For: $1" "http://$address$2" || true
}

# refused: a request to the container gets 403, SWW_WAF_BAN_RESPONSE's
# default.
refused() {
    code="$(curl --silent --output /dev/null --write-out '%{http_code}' \
        --max-time 10 "http://$address/")" || true
    [ "$code" = 403 ]
}

# refused_from <client> <path>: a request for path from client gets 403.
refused_from() {
    [ "$(status_from "$1" "$2")" = 403 ]
}

# owner_of_state_dir <container>: print who owns /var/lib/sww there.
owner_of_state_dir() {
    docker exec "$1" stat --format '%U' /var/lib/sww
}

main() {
    cd "$ROOT"
    trap cleanup EXIT
    trap 'exit 1' HUP INT TERM

    docker build --no-cache -t "$IMAGE" .
    docker build --no-cache --build-arg SWW_IMAGE="$IMAGE" \
        -t "$APP_IMAGE" deploy/example-app

    docker network create "$NETWORK" >/dev/null
    docker volume create "$VOLUME" >/dev/null
    start_discriminator
    start_app
    echo "example-app: the health checks pass"

    [ "$(owner_of_state_dir "$DISCRIMINATOR")" = sww ] ||
        fail "discriminator's container did not give the state directory to sww"
    [ "$(owner_of_state_dir "$APP")" = root ] ||
        fail "the app's container changed the state directory's owner"
    echo "example-app: only discriminator's container changes the state directory's owner"

    page="$(curl --fail --silent --show-error --max-time 10 "http://$address/")" ||
        fail "no answer on port 8080"
    [ "$page" = "hello from the example app" ] || fail "port 8080 answered $page"
    wait_for "discriminator logged no request it allowed" \
        logged "$DISCRIMINATOR" '"action":"forward"' '"discriminator_line":"report"'
    echo "example-app: rproxy passes a request to the app and its answer back"

    refused || fail "a second request in a minute was not refused"
    wait_for "discriminator logged no ban" logged "$DISCRIMINATOR" '"action":"rate_limited"'
    echo "example-app: a second request in a minute bans the client"

    refused_from 203.0.113.9 /.env || fail "a probe for /.env was not refused"
    wait_for "discriminator logged no ban for the probe" \
        logged "$DISCRIMINATOR" '"action":"banned"' '"rule_ids":["env-file"]'
    refused_from 203.0.113.9 / || fail "the client of the probe was let through"
    wait_for "the client's next request did not make its ban permanent" \
        logged "$DISCRIMINATOR" '"ban_expires":"permanent"'
    echo "example-app: a probe for /.env bans the client, its next request for good"

    docker exec "$DISCRIMINATOR" sv stop sww >/dev/null ||
        fail "sv stop sww failed in discriminator's container"
    wait_for "discriminator did not stop in order" logged "$DISCRIMINATOR" '"msg":"stopped"'
    [ "$(status_from 203.0.113.9 /)" = 200 ] ||
        fail "with discriminator stopped, the app did not answer through rproxy"
    wait_for "rproxy logged no request SWW_RPROXY_DEFAULT_DISPOSITION decided" \
        logged "$APP" '"default_disposition":true'
    docker exec "$APP" /usr/local/bin/sww healthcheck ||
        fail "with discriminator stopped, the app's health check failed"
    echo "example-app: with discriminator stopped, the app answers through rproxy"

    docker exec "$DISCRIMINATOR" sv start sww >/dev/null ||
        fail "sv start sww failed in discriminator's container"
    wait_for "once discriminator had started again, the ban did not apply" \
        refused_from 203.0.113.9 /
    echo "example-app: once discriminator has started again, bans apply again"

    docker exec "$APP" sv stop sww >/dev/null ||
        fail "sv stop sww failed in the app's container"
    wait_for "rproxy did not stop in order" logged "$APP" '"msg":"stopped"'
    echo "example-app: sv stop stops rproxy in order"

    for container in "$APP" "$DISCRIMINATOR"; do
        docker stop "$container" >/dev/null
        status="$(docker inspect --format '{{.State.ExitCode}}' "$container")"
        [ "$status" = 0 ] || fail "docker stop left exit status $status"
    done
    echo "example-app: docker stop stops each container in order"

    docker rm "$APP" "$DISCRIMINATOR" >/dev/null
    start_discriminator
    start_app
    refused || fail "the new discriminator container let the banned client through"
    wait_for "discriminator logged no request refused under the ban" \
        logged "$DISCRIMINATOR" '"action":"banned"'
    echo "example-app: a new discriminator container on the same volume keeps the ban"

    docker rm --force "$DISCRIMINATOR" >/dev/null
    start_moved_discriminator
    echo "example-app: the run script gives the state files' directory named" \
        "by SWW_WAF_STATE_DIR_FILE to the sww user"

    docker rm --force "$DISCRIMINATOR" >/dev/null
    docker run --detach --name "$DISCRIMINATOR" --network "$NETWORK" \
        --env SWW_COMMAND=discriminator \
        --env SWW_WAF_STATE_DIR=/srv/missing \
        --env SWW_WAF_LOOKUP_SOURCE=off \
        "$IMAGE" >/dev/null
    wait_for "discriminator did not report the missing state directory" \
        logged "$DISCRIMINATOR" "SWW_WAF_STATE_DIR cannot be written"
    echo "example-app: discriminator reports a state directory that does not exist"
}

main "$@"