Add script to download and install Backblaze CLI tool (#1748)

Related tiny-pilot/tinypilot-pro#1231
Related tiny-pilot/tinypilot-pro#1229

While working on tiny-pilot/tinypilot-pro#1246,
we needed to install the Backblaze CLI tool yet again. This PR moves the
download and installation of `b2` to a dedicated script.

Notes:
1. We've also updated the CircleCI image to the latest version because
[it comes pre-installed with the `wget`
command](https://codeapprove.com/pr/tiny-pilot/tinypilot-pro/1246#thread-b6949a01-6558-4619-a0ff-47ddb4dc9597).

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.circleci/config.yml

@@ -225,10 +225,11 @@ jobs:
           command: ./bundler/verify-bundle
   upload_bundle:
     docker:
-      - image: cimg/base:2020.01
+      - image: cimg/base:2024.02
     environment:
       UPLOAD_PREFIX: community
     steps:
+      - checkout
       - attach_workspace:
           at: ./
       - run:
@@ -237,17 +238,8 @@ jobs:
           name: Create LATEST file
           command: cd dist && ls tinypilot*.tgz | tee LATEST
       - run:
-          name: Download Backblaze CLI tool
-          command: |
-            sudo apt-get update && sudo apt-get install -y wget
-            wget https://github.com/Backblaze/B2_Command_Line_Tool/releases/download/v3.4.0/b2-linux --output-document=./b2
-            chmod +x ./b2
-            ./b2 version
-      - run:
-          name: Authorize Backblaze CLI tool
-          command: |
-            set -u
-            ./b2 authorize-account "${BACKBLAZE_KEY_ID}" "${BACKBLAZE_KEY}"
+          name: Setup Backblaze CLI tool
+          command: ./bundler/setup-b2-linux
       - run:
           name: Upload bundle to Backblaze
           command: |

bundler/setup-b2-linux

@@ -0,0 +1,40 @@
+#!/bin/bash
+#
+# Setup and configure the Backblaze CLI tool for a Linux based system.
+#
+# This includes the download, installation, and account authorization.
+
+# Exit script on first failure.
+set -e
+
+# Determine if there are any account credentials available.
+if [[ -n "${BACKBLAZE_KEY_ID}" ]] && [[ -n "${BACKBLAZE_KEY}" ]]; then
+  readonly HAS_CREDENTIALS='true'
+else
+  readonly HAS_CREDENTIALS='false'
+fi
+
+# Exit on unset variable.
+set -u
+
+# Download and install the Backblaze CLI tool, if it doesn't already exist.
+if [[ ! -f ./b2 ]]; then
+  readonly VERSION='3.4.0'
+  wget \
+    "https://github.com/Backblaze/B2_Command_Line_Tool/releases/download/v${VERSION}/b2-linux" \
+    --output-document ./b2 \
+    --no-verbose
+  chmod +x ./b2
+fi
+
+# Print current version.
+./b2 version
+
+# Authorize the Backblaze account, if account credentials are available.
+if "${HAS_CREDENTIALS}"; then
+  ./b2 authorize-account "${BACKBLAZE_KEY_ID}" "${BACKBLAZE_KEY}"
+else
+  echo 'No Backblaze account credentials were found.'
+  echo 'Manually authorize your account using the following command:'
+  echo '  ./b2 authorize-account'
+fi