Add a script to download the latest version. (#134)

This facilitates use in CI.

Author: FGasper

README.md

@@ -3,9 +3,12 @@
 _If verifying a migration done via [mongosync](https://www.mongodb.com/docs/cluster-to-cluster-sync/current/), please check if it is possible to use the 
 [embedded verifier](https://www.mongodb.com/docs/cluster-to-cluster-sync/current/reference/verification/embedded/#std-label-c2c-embedded-verifier) as that is the preferred approach for verification._
 
-# To build
-
-
+# Obtaining
+To fetch the latest release:
+```
+curl -sSL https://raw.githubusercontent.com/mongodb-labs/migration-verifier/refs/heads/main/download_latest.sh | sh
+```
+… or, if you prefer to build locally, just do:
 ```
 ./build.sh
 ```

download_latest.sh

@@ -0,0 +1,43 @@
+#!/bin/sh
+
+set -o errexit
+
+filename=migration_verifier
+
+RELEASE_URL="https://api.github.com/repos/mongodb-labs/migration-verifier/releases/latest"
+
+OS=$(uname -o | tr '[:upper:]' '[:lower:]' | sed 's|gnu/||')
+ARCH=$(uname -m)
+if [ "$ARCH" = "aarch64" ]; then
+    ARCH=arm64
+fi
+
+echo "Looks like you’re running $OS on $ARCH."
+
+MANIFEST=$(curl -sSL "$RELEASE_URL")
+
+VERSION=$(printf "%s" "$MANIFEST" | jq -r .name)
+
+echo "Latest release: $VERSION"
+
+ALL_URLS=$(printf "%s" "$MANIFEST" \
+    | jq -r '.assets[] | .browser_download_url' \
+)
+
+DOWNLOAD_URL=$(echo "$ALL_URLS" \
+    | grep "_${OS}_" | grep "_$ARCH" ||: \
+)
+
+if [ -z "$DOWNLOAD_URL" ]; then
+    echo >&2 "No download URL found for $OS/$ARCH:"
+    echo >&2 "$ALL_URLS"
+    exit 1
+fi
+
+echo "Downloading $DOWNLOAD_URL …"
+
+curl -sSL "$DOWNLOAD_URL" > "$filename"
+
+chmod +x "$filename"
+
+echo "✅ Migration Verifier $VERSION is now saved as $filename."