From 435907d68de26f330dbc7ac1cfb4eb7c2c146076 Mon Sep 17 00:00:00 2001
From: Daniel Moran <danxmoran@gmail.com>
Date: Wed, 3 Nov 2021 15:16:24 -0400
Subject: [PATCH] build: add a CI job to test `influxd downgrade` (#22822)

---
 .circleci/config.yml         |  15 +++++
 scripts/ci/test-downgrade.sh | 115 +++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100755 scripts/ci/test-downgrade.sh

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 304085570ce..46e7d15d5cb 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -110,6 +110,9 @@ workflows:
       - cross_build:
           requires:
             - godeps
+      - test-downgrade:
+          requires:
+            - build
       - e2e-monitor-ci:
           filters:
             branches:
@@ -1110,6 +1113,18 @@ jobs:
       - store_test_results:
           path: ~/project/results
 
+  test-downgrade:
+    executor: cross-builder
+    working_directory: /home/circleci/go/src/github.com/influxdata/influxdb
+    steps:
+      - checkout
+      - attach_workspace:
+          at: /home/circleci/go/src/github.com/influxdata/influxdb
+      - run:
+          name: Run downgrade tests
+          command: |
+            ./scripts/ci/test-downgrade.sh $(pwd)/dist/influxd_linux_amd64/influxd
+
   share-testing-image:
     executor: linux-amd64
     working_directory: /home/circleci/go/src/github.com/influxdata/influxdb
diff --git a/scripts/ci/test-downgrade.sh b/scripts/ci/test-downgrade.sh
new file mode 100755
index 00000000000..25154ebde29
--- /dev/null
+++ b/scripts/ci/test-downgrade.sh
@@ -0,0 +1,115 @@
+#!/usr/bin/env bash
+set -exo pipefail
+
+declare -a DOWNGRADE_TARGETS=('2.0')
+
+declare -r TEST_ORG=testorg
+declare -r TEST_TOKEN=supersecretfaketoken
+declare -r INIT_PING_ATTEMPTS=600
+
+function download_older_binary () {
+    local -r target_version=$1 dl_dir=$2
+
+    local dl_url
+    local dl_sha
+    case ${target_version} in
+        2.0)
+            dl_url=https://dl.influxdata.com/influxdb/releases/influxdb2-2.0.9-linux-amd64.tar.gz
+            dl_sha=64b9cfea1b5ca07479a16332056f9e7f806ad71df9c6cc0ec70c4333372b9d26
+            ;;
+        *)
+            >&2 echo Error: Unknown downgrade target "'$target_version'"
+            exit 1
+            ;;
+    esac
+
+    local -r archive="influxd-${target_version}.tar.gz"
+    curl -sL -o "${dl_dir}/${archive}" "$dl_url"
+    echo "${dl_sha}  ${dl_dir}/${archive}" | sha256sum --check --
+    tar xzf "${dl_dir}/${archive}" -C "$dl_dir" --strip-components=1
+    rm "${dl_dir}/${archive}"
+    mv "${dl_dir}/influxd" "${dl_dir}/influxd-${target_version}"
+}
+
+function test_downgrade_target () {
+    local -r influxd_path=$1 target_version=$2 tmp=$3
+
+    download_older_binary "$target_version" "$tmp"
+
+    local -r bolt_path="${tmp}/influxd-${target_version}.bolt"
+    local -r sqlite_path="${tmp}/influxd-${target_version}.sqlite"
+
+    cp "${tmp}/influxd.bolt" "$bolt_path"
+    cp "${tmp}/influxd.sqlite" "$sqlite_path"
+
+    "$influxd_path" downgrade \
+        --bolt-path "$bolt_path" \
+        --sqlite-path "$sqlite_path" \
+        "$target_version"
+
+    INFLUXD_BOLT_PATH="$bolt_path" INFLUXD_SQLITE_PATH="$sqlite_path" INFLUXD_ENGINE_PATH="${tmp}/engine" \
+        "${tmp}/influxd-${target_version}" &
+    local -r influxd_pid="$!"
+
+    wait_for_influxd "$influxd_pid"
+
+    if [[ "$(curl -s -o /dev/null -H "Authorization: Token $TEST_TOKEN" "http://localhost:8086/api/v2/me" -w "%{http_code}")" != "200" ]]; then
+        >&2 echo Error: "Downgraded DB doesn't recognize auth token"
+        exit 1
+    fi
+
+    kill -TERM "$influxd_pid"
+    wait "$influxd_pid" || true
+}
+
+function wait_for_influxd () {
+    local -r influxd_pid=$1
+    local ping_count=0
+    while kill -0 "${influxd_pid}" && [ ${ping_count} -lt ${INIT_PING_ATTEMPTS} ]; do
+        sleep 1
+        ping_count=$((ping_count+1))
+        if [[ "$(curl -s -o /dev/null "http://localhost:8086/health" -w "%{http_code}")" = "200" ]]; then
+            return
+        fi
+    done
+    if [ ${ping_count} -eq ${INIT_PING_ATTEMPTS} ]; then
+        >&2 echo influxd took too long to start up
+    else
+        >&2 echo influxd crashed during startup
+    fi
+    return 1
+}
+
+function setup_influxd () {
+    local -r influxd_path=$1 tmp=$2
+    INFLUXD_BOLT_PATH="${tmp}/influxd.bolt" INFLUXD_SQLITE_PATH="${tmp}/influxd.sqlite" INFLUXD_ENGINE_PATH="${tmp}/engine" \
+        "$influxd_path" &
+    local -r influxd_pid="$!"
+
+    wait_for_influxd "$influxd_pid"
+    curl -s -o /dev/null -XPOST \
+        -d '{"username":"default","password":"fakepassword","org":"'$TEST_ORG'","bucket":"unused","token":"'$TEST_TOKEN'"}' \
+        http://localhost:8086/api/v2/setup
+
+    kill -TERM "$influxd_pid"
+    wait "$influxd_pid" || true
+}
+
+function main () {
+    if [[ $# != 1 ]]; then
+        >&2 echo Usage: $0 '<influxd-path>'
+        exit 1
+    fi
+    local -r influxd_path=$1
+
+    local -r tmp="$(mktemp -d -t "test-downgrade-${target_version}-XXXXXX")"
+    trap "rm -rf ${tmp}" EXIT
+
+    setup_influxd "$influxd_path" "$tmp"
+
+    for target in ${DOWNGRADE_TARGETS[@]}; do
+        test_downgrade_target "$influxd_path" "$target" "$tmp"
+    done
+}
+
+main "${@}"