Add check-db continuity script to migrate.sh (#32)

Adds a call to the check-db script in celo-migrate to migrate.sh.
This checks for gaps in the source directory and exits
immediately if gaps are found.

Adds some drive-by changes for things that came up during testing:

destination dir path should include "chaindata"
calls to readlink fail if path does not exist, so we check that the source directory exists before calling readlink on it
Tested locally using a baklava datadir with gaps and a baklava datadir without gaps

migrate.sh

@@ -42,18 +42,42 @@ echo "Source Directory: $source_dir"
 echo "Destination Directory: $destination_dir"
 echo "" # Blank line to separate from any failure output
 
-# Convert source and destination directories to absolute paths
+# Check if source directory exists
+if [ ! -d "${source_dir}" ]; then
+    printf "\033[0;31mError: Source directory does not exist\033[0m\n"
+    exit 1
+fi
+
+# Convert source directory to absolute path
 source_dir=$(readlink -f "$source_dir")
-destination_dir=$(readlink -f "$destination_dir")
+
+cel2_migration_tool_image="us-west1-docker.pkg.dev/devopsre/celo-blockchain-public/cel2-migration-tool"
+cel2_migration_tool_tag="5682b80ec60c47f582c6af8aa085ae6f9048d801"
+
+# Run check-db continuity script to ensure source db has no data gaps
+if docker run --platform=linux/amd64 -it --rm \
+    -v "${source_dir}/celo/chaindata:/old-db" \
+    "${cel2_migration_tool_image}:${cel2_migration_tool_tag}" \
+    check-db \
+      --db-path /old-db \
+      --fail-fast; then
+    printf "\033[0;32mDB check completed successfully. No gaps or missing data detected.\033[0m\n"
+else
+    printf "\033[0;31mDB check failed with exit code $?. If the logs indicate that the db is missing data, please retry with another source db. You can visit https://docs.celo.org/cel2/operators/migrate-node for instructions on how to check whether a db has missing data.\033[0m\n"
+    exit $?
+fi
 
 # Ensure destination directory exists for chaindata
-mkdir -p  "${destination_dir}/geth"
+mkdir -p  "${destination_dir}/geth/chaindata"
+
+# Convert destination directory to absolute path
+destination_dir=$(readlink -f "$destination_dir")
 
 if [ "${operation}" = "pre" ]; then
   docker run --platform=linux/amd64 -it --rm \
     -v "${source_dir}/celo/chaindata:/old-db" \
     -v "${destination_dir}/geth/chaindata:/new-db" \
-    us-west1-docker.pkg.dev/devopsre/celo-blockchain-public/cel2-migration-tool:5682b80ec60c47f582c6af8aa085ae6f9048d801 \
+    "${cel2_migration_tool_image}:${cel2_migration_tool_tag}" \
     "${operation}" \
       --old-db /old-db \
       --new-db /new-db
@@ -85,7 +109,7 @@ docker run --platform=linux/amd64 -it --rm \
   -v "${destination_dir}/geth/chaindata:/new-db" \
   -v "${migration_config_dir}:/migration-config" \
   -v "./envs/${network}/config:/out-config" \
-  us-west1-docker.pkg.dev/devopsre/celo-blockchain-public/cel2-migration-tool:5682b80ec60c47f582c6af8aa085ae6f9048d801 \
+  "${cel2_migration_tool_image}:${cel2_migration_tool_tag}" \
   "${operation}" \
     --old-db /old-db \
     --new-db /new-db \