Duplicate MySQL backend, then search'n'replace a bunch of stuff

postgresql_trillian.sh

#!/bin/bash

git checkout -b duplicate_mysql_to_postgresql

# Duplicate the MySQL quota.Manager and storage layer files into new PostgreSQL directories, preserving git line history.
# (h/t https://devblogs.microsoft.com/oldnewthing/20190919-00/?p=102904)
mkdir quota/postgresqlqm
git mv quota/mysqlqm/mysql_quota.go quota/postgresqlqm/postgresql_quota.go
git mv quota/mysqlqm/mysql_quota_test.go quota/postgresqlqm/postgresql_quota_test.go
git mv quota/mysqlqm/quota_provider.go quota/postgresqlqm
mkdir storage/postgresql
git mv storage/mysql/* storage/postgresql
git mv storage/postgresql/mysqlpb storage/postgresql/postgresqlpb
mkdir storage/postgresql/testdbpgx
git mv storage/testdb/testdb.go storage/postgresql/testdbpgx/testdbpgx.go
git mv storage/testdb/testdb_test.go storage/postgresql/testdbpgx/testdbpgx_test.go
git commit -m "Duplicate MySQL files to new PostgreSQL directories, preserving git line history"
git checkout HEAD~ quota/mysqlqm storage/mysql storage/testdb
git commit -m "Restore MySQL files"
git checkout -
git checkout -b postgresql_support
git merge --no-ff --no-edit duplicate_mysql_to_postgresql
git branch -D duplicate_mysql_to_postgresql

# Replace "MySQL" references with "PostgreSQL", preserving case of each reference.
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/mysql/postgresql/g" '{}' ';'
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/MySQL/PostgreSQL/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/mysql/postgresql/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/MySQL/PostgreSQL/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/mySQL/postgreSQL/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/Mysql/Postgresql/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/MYSQL/POSTGRESQL/g" '{}' ';'
sed -i "s/MySQL/PostgreSQL/g" storage/postgresql/schema/storage.sql
sed -i "s/MySQL/PostgreSQL/g" storage/postgresql/postgresqlpb/options.proto
sed -i "s/mysql/postgresql/g" storage/postgresql/postgresqlpb/options.proto
git commit -a -m "Replace 'MySQL' references with 'PostgreSQL', preserving case of each reference"

# Build the PostgreSQL protobuf definitions.
cd storage/postgresql/postgresqlpb
go generate
cd ../../..
git commit -a -m "Build the PostgreSQL protobuf definitions"

# Rename PostgreSQL "testdb" package to "testdbpgx".
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/\"github.com\/google\/trillian\/storage\/testdb/testdb \"github.com\/google\/trillian\/storage\/postgresql\/testdbpgx/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/\"github.com\/google\/trillian\/storage\/testdb/testdb \"github.com\/google\/trillian\/storage\/postgresql\/testdbpgx/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/package testdb/package testdbpgx/g" '{}' ';'
git commit -a -m "Rename PostgreSQL 'testdb' package to 'testdbpgx'"

# Convert from database/sql API to jackc/pgx/v5 API.
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/sql\.DB/pgxpool\.Pool/g" '{}' ';'          # "sql.DB" -> "pgxpool.Pool".
find storage/postgresql -iname "*.go" -exec sed -i "s/sql\.DB/pgxpool\.Pool/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/sql\.Open/pgxpool\.New/g" '{}' ';'         # "sql.Open" -> "pgxpool.New".
find storage/postgresql -iname "*.go" -exec sed -i "s/sql\.Result/pgconn\.CommandTag/g" '{}' ';' # "sql.Result" -> "pgconn.CommandTag".
find storage/postgresql -iname "*.go" -exec sed -i "s/\*sql\.Rows/pgx\.Rows/g" '{}' ';'          # "*sql.Rows" -> "pgx.Rows".
find storage/postgresql -iname "*.go" -exec sed -i "s/\*sql\.Tx/pgx\.Tx/g" '{}' ';'              # "*sql.Tx" -> "pgx.Tx".
find storage/postgresql -iname "*.go" -exec sed -i "s/sql\.ErrNoRows/pgx\.ErrNoRows/g" '{}' ';'  # "sql.ErrNoRows" -> "pgx.ErrNoRows".
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/ExecContext/Exec/g" '{}' ';'               # "ExecContext" -> "Exec".
find storage/postgresql -iname "*.go" -exec sed -i "s/ExecContext/Exec/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/PingContext/Ping/g" '{}' ';'               # "PingContext" -> "Ping".
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/QueryContext/Query/g" '{}' ';'             # "QueryContext" -> "Query".
find storage/postgresql -iname "*.go" -exec sed -i "s/QueryContext/Query/g" '{}' ';'
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/QueryRowContext/QueryRow/g" '{}' ';'       # "QueryRowContext" -> "QueryRow".
find storage/postgresql -iname "*.go" -exec sed -i "s/QueryRowContext/QueryRow/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/nil \/\* opts \*\//pgx.TxOptions\{\}/g" '{}' ';'  # "nil /* opts */" -> "pgx.TxOptions{}".
git commit -a -m "Convert from database/sql API to jackc/pgx/v5 API"

# Update imports.
echo "Using gopls to update imports.  Please wait..."
find storage/postgresql -iname "*.go" -exec sed -i "s/go-sql-driver\/postgresql/jackc\/pgx\/v5\/pgxpool/g" '{}' ';'
sed -i "s/build batched_queue/IGNOREbuild batched_queue/g" storage/postgresql/queue_batching.go
find quota/postgresqlqm -iname "*.go" -exec gopls imports -w '{}' ';' 2>/dev/null  # These first two 'gopls imports' are only partially successful and emit some errors.
find storage/postgresql -iname "*.go" -exec gopls imports -w '{}' ';' 2>/dev/null
find quota/postgresqlqm -iname "*.go" -exec sed -i "s/jackc\/pgx\/v4\/pgxpool/jackc\/pgx\/v5\/pgxpool/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/jackc\/pgx\/v4\/pgxpool/jackc\/pgx\/v5\/pgxpool/g" '{}' ';'
find storage/postgresql -iname "*.go" -exec sed -i "s/jackc\/pgx\"/jackc\/pgx\/v5\"/g" '{}' ';'
go mod tidy
find quota/postgresqlqm -iname "*.go" -exec gopls imports -w '{}' ';'  # Repeating the 'gopls imports' should succeed without errors.
find storage/postgresql -iname "*.go" -exec gopls imports -w '{}' ';'
sed -i "s/IGNOREbuild batched_queue/build batched_queue/g" storage/postgresql/queue_batching.go
git commit -a -m "Update imports"