Module: PgEasyReplicate

Extended by:
Helper
Defined in:
lib/pg_easy_replicate.rb,
lib/pg_easy_replicate/cli.rb,
lib/pg_easy_replicate/group.rb,
lib/pg_easy_replicate/query.rb,
lib/pg_easy_replicate/stats.rb,
lib/pg_easy_replicate/helper.rb,
lib/pg_easy_replicate/version.rb,
lib/pg_easy_replicate/orchestrate.rb,
lib/pg_easy_replicate/index_manager.rb

Defined Under Namespace

Modules: Helper, IndexManager Classes: CLI, Error, Group, Orchestrate, Query, Stats

Constant Summary collapse

SCHEMA_FILE_LOCATION = 
"/tmp/pger_schema.sql"
VERSION = 
"0.2.7"

Class Method Summary collapse

Methods included from Helper

abort_with, connection_info, convert_to_array, db_name, db_user, determine_tables, internal_schema_name, internal_user_name, list_all_tables, logger, publication_name, quote_ident, secondary_source_db_url, source_db_url, subscription_name, target_db_url, test_env?, underscore, validate_table_lists

Class Method Details

.assert_config(special_user_role: nil, copy_schema: false, tables: "", exclude_tables: "", schema_name: nil) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 84

def assert_config(
  special_user_role: nil,
  copy_schema: false,
  tables: "",
  exclude_tables: "",
  schema_name: nil
)
  config_hash =
    config(
      special_user_role: special_user_role,
      copy_schema: copy_schema,
      tables: tables,
      exclude_tables: exclude_tables,
      schema_name: schema_name,
    )

  if copy_schema && !config_hash.dig(:pg_dump_exists)
    abort_with("pg_dump must exist if copy_schema (-c) is passed")
  end

  unless assert_wal_level_logical(config_hash.dig(:source_db))
    abort_with("WAL_LEVEL should be LOGICAL on source DB")
  end

  unless assert_wal_level_logical(config_hash.dig(:target_db))
    abort_with("WAL_LEVEL should be LOGICAL on target DB")
  end

  unless config_hash.dig(:source_db_is_super_user)
    abort_with("User on source database does not have super user privilege")
  end

  validate_table_lists(tables, exclude_tables, schema_name)

  unless config_hash.dig(:tables_have_replica_identity)
    abort_with(
      "Ensure all tables involved in logical replication have an appropriate replica identity set. This can be done using:
    1. Default (Primary Key): `ALTER TABLE table_name REPLICA IDENTITY DEFAULT;`
    2. Unique Index: `ALTER TABLE table_name REPLICA IDENTITY USING INDEX index_name;`
    3. Full (All Columns): `ALTER TABLE table_name REPLICA IDENTITY FULL;`",
    )
  end

  return if config_hash.dig(:target_db_is_super_user)
  abort_with("User on target database does not have super user privilege")
end

.assert_wal_level_logical(db_config) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 293

def assert_wal_level_logical(db_config)
  db_config&.find do |r|
    r.dig(:name) == "wal_level" && r.dig(:setting) == "logical"
  end
end

.bootstrap(options) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 131

def bootstrap(options)
  logger.info("Setting up schema")
  setup_internal_schema

  if options[:copy_schema]
    logger.info("Setting up schema on target database")
    copy_schema(
      source_conn_string: source_db_url,
      target_conn_string: target_db_url,
    )
  end

  logger.info("Setting up replication user on source database")
  create_user(
    conn_string: source_db_url,
    special_user_role: options[:special_user_role],
    grant_permissions_on_schema: true,
  )

  logger.info("Setting up replication user on target database")
  create_user(
    conn_string: target_db_url,
    special_user_role: options[:special_user_role],
  )

  logger.info("Setting up groups tables")
  Group.setup
rescue => e
  abort_with("Unable to bootstrap: #{e.message}")
end

.cleanup(options) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 162

def cleanup(options)
  cleanup_steps = [
    -> do
      logger.info("Dropping groups table")
      Group.drop
    end,
    -> do
      if options[:everything]
        logger.info("Dropping schema")
        drop_internal_schema
      end
    end,
    -> do
      if options[:everything] || options[:sync]
        logger.info("Dropping publication on source database")
        Orchestrate.drop_publication(
          group_name: options[:group_name],
          conn_string: source_db_url,
        )
      end
    end,
    -> do
      if options[:everything] || options[:sync]
        logger.info("Dropping subscription on target database")
        Orchestrate.drop_subscription(
          group_name: options[:group_name],
          target_conn_string: target_db_url,
        )
      end
    end,
    -> do
      if options[:everything]
        logger.info("Dropping replication user on source database")
        drop_user(conn_string: source_db_url)
      end
    end,
    -> do
      if options[:everything]
        logger.info("Dropping replication user on target database")
        drop_user(conn_string: target_db_url)
      end
    end,
  ]

  cleanup_steps.each do |step|
    step.call
  rescue => e
    logger.warn(
      "Part of the cleanup step failed with #{e.message}. Continuing...",
    )
  end

  logger.info("Cleanup process completed.")
rescue => e
  abort_with("Unable to cleanup: #{e.message}")
end

.config(special_user_role: nil, copy_schema: false, tables: "", exclude_tables: "", schema_name: nil) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 29

def config(
  special_user_role: nil,
  copy_schema: false,
  tables: "",
  exclude_tables: "",
  schema_name: nil
)
  abort_with("SOURCE_DB_URL is missing") if source_db_url.nil?
  abort_with("TARGET_DB_URL is missing") if target_db_url.nil?

  if !tables.empty? && !exclude_tables.empty?
    abort_with(
      "Options --tables(-t) and --exclude-tables(-e) cannot be used together.",
    )
  end

  system("which pg_dump")
  pg_dump_exists = $CHILD_STATUS.success?

  @config ||=
    begin
      q =
        "select name, setting from pg_settings where name in  ('max_wal_senders', 'max_worker_processes', 'wal_level',  'max_replication_slots', 'max_logical_replication_workers');"

      {
        source_db_is_super_user:
          is_super_user?(source_db_url, special_user_role),
        target_db_is_super_user:
          is_super_user?(target_db_url, special_user_role),
        source_db:
          Query.run(
            query: q,
            connection_url: source_db_url,
            user: db_user(source_db_url),
          ),
        target_db:
          Query.run(
            query: q,
            connection_url: target_db_url,
            user: db_user(target_db_url),
          ),
        pg_dump_exists: pg_dump_exists,
        tables_have_replica_identity:
          tables_have_replica_identity?(
            conn_string: source_db_url,
            tables: tables,
            exclude_tables: exclude_tables,
            schema_name: schema_name,
          ),
      }
    rescue => e
      abort_with("Unable to check config: #{e.message}")
    end
end

.copy_schema(source_conn_string:, target_conn_string:) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 259

def copy_schema(source_conn_string:, target_conn_string:)
  export_schema(conn_string: source_conn_string)
  import_schema(conn_string: target_conn_string)
end

.create_user(conn_string:, special_user_role: nil, grant_permissions_on_schema: false) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 329

def create_user(
  conn_string:,
  special_user_role: nil,
  grant_permissions_on_schema: false
)
  return if user_exists?(conn_string: conn_string, user: internal_user_name)

  password = connection_info(conn_string)[:password].gsub("'") { "''" }

  sql = "    create role \#{quote_ident(internal_user_name)} with password '\#{password}' login createdb createrole;\n    grant all privileges on database \#{quote_ident(db_name(conn_string))} TO \#{quote_ident(internal_user_name)};\n  SQL\n\n  Query.run(\n    query: sql,\n    connection_url: conn_string,\n    user: db_user(conn_string),\n    transaction: false,\n  )\n\n  sql =\n    if special_user_role\n      \"grant \#{quote_ident(special_user_role)} to \#{quote_ident(internal_user_name)};\"\n    else\n      \"alter user \#{quote_ident(internal_user_name)} with superuser;\"\n    end\n\n  Query.run(\n    query: sql,\n    connection_url: conn_string,\n    user: db_user(conn_string),\n    transaction: false,\n  )\n\n  return unless grant_permissions_on_schema\n  Query.run(\n    query:\n      \"grant all on schema \#{quote_ident(internal_schema_name)} to \#{quote_ident(internal_user_name)}\",\n    connection_url: conn_string,\n    user: db_user(conn_string),\n    transaction: false,\n  )\nrescue => e\n  raise \"Unable to create user: \#{e.message}\"\nend\n"

.drop_internal_schema ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 219

def drop_internal_schema
  Query.run(
    query:
      "DROP SCHEMA IF EXISTS #{quote_ident(internal_schema_name)} CASCADE",
    connection_url: source_db_url,
    schema: internal_schema_name,
    user: db_user(source_db_url),
  )
rescue => e
  raise "Unable to drop schema: #{e.message}"
end

.drop_user(conn_string:, user: internal_user_name) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 376

def drop_user(conn_string:, user: internal_user_name)
  return unless user_exists?(conn_string: conn_string, user: user)

  sql = "   revoke all privileges on database \#{quote_ident(db_name(conn_string))} from \#{quote_ident(user)};\n  SQL\n\n  Query.run(\n    query: sql,\n    connection_url: conn_string,\n    user: db_user(conn_string),\n  )\n\n  sql = <<~SQL\n    drop role if exists \#{quote_ident(user)};\n  SQL\n\n  Query.run(\n    query: sql,\n    connection_url: conn_string,\n    user: db_user(conn_string),\n  )\nrescue => e\n  raise \"Unable to drop user: \#{e.message}\"\nend\n"

.export_schema(conn_string:) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 264

def export_schema(conn_string:)
  logger.info("Exporting schema to #{SCHEMA_FILE_LOCATION}")
  _, stderr, status =
    Open3.capture3(
      "pg_dump",
      conn_string,
      "-f",
      SCHEMA_FILE_LOCATION,
      "--schema-only",
    )

  success = status.success?
  raise stderr unless success
rescue => e
  raise "Unable to export schema: #{e.message}"
end

.import_schema(conn_string:) ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 281

def import_schema(conn_string:)
  logger.info("Importing schema from #{SCHEMA_FILE_LOCATION}")

  _, stderr, status =
    Open3.capture3("psql", "-f", SCHEMA_FILE_LOCATION, conn_string)

  success = status.success?
  raise stderr unless success
rescue => e
  raise "Unable to import schema: #{e.message}"
end

.is_super_user?(url, special_user_role = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_easy_replicate.rb', line 299

def is_super_user?(url, special_user_role = nil)
  if special_user_role
    sql = "      SELECT r.rolname AS username,\n        r1.rolname AS \"role\"\n      FROM pg_catalog.pg_roles r\n      LEFT JOIN pg_catalog.pg_auth_members m ON (m.member = r.oid)\n      LEFT JOIN pg_roles r1 ON (m.roleid=r1.oid)\n      WHERE r.rolname = '\#{db_user(url)}'\n      ORDER BY 1;\n    SQL\n\n    r = Query.run(query: sql, connection_url: url, user: db_user(url))\n    # If special_user_role is passed just ensure the url in conn_string has been granted\n    # the special_user_role\n    r.any? { |q| q[:role] == special_user_role }\n  else\n    r =\n      Query.run(\n        query:\n          \"SELECT rolname, rolsuper FROM pg_roles where rolname = '\#{db_user(url)}';\",\n        connection_url: url,\n        user: db_user(url),\n      )\n    r.any? { |q| q[:rolsuper] }\n  end\nrescue => e\n  raise \"Unable to check superuser conditions: \#{e.message}\"\nend\n"

.logger ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 248

def logger
  @logger ||=
    begin
      logger = Ougai::Logger.new($stdout)
      logger.level =
        ENV["DEBUG"] ? Ougai::Logger::TRACE : Ougai::Logger::INFO
      logger.with_fields = { version: PgEasyReplicate::VERSION }
      logger
    end
end

.setup_internal_schema ⇒ Object 



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# File 'lib/pg_easy_replicate.rb', line 231

def setup_internal_schema
  sql = "    create schema if not exists \#{quote_ident(internal_schema_name)};\n    grant usage on schema \#{quote_ident(internal_schema_name)} to \#{quote_ident(db_user(source_db_url))};\n    grant create on schema \#{quote_ident(internal_schema_name)} to \#{quote_ident(db_user(source_db_url))};\n  SQL\n\n  Query.run(\n    query: sql,\n    connection_url: source_db_url,\n    schema: internal_schema_name,\n    user: db_user(source_db_url),\n  )\nrescue => e\n  raise \"Unable to setup schema: \#{e.message}\"\nend\n"

.tables_have_replica_identity?(conn_string:, tables: "", exclude_tables: "", schema_name: nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_easy_replicate.rb', line 422

def tables_have_replica_identity?(
  conn_string:,
  tables: "",
  exclude_tables: "",
  schema_name: nil
)
  schema_name ||= "public"

  table_list =
    determine_tables(
      schema: schema_name,
      conn_string: source_db_url,
      list: tables,
      exclude_list: exclude_tables,
    )
  return false if table_list.empty?

  formatted_table_list = table_list.map { |table| "'#{table}'" }.join(", ")

  sql = "    SELECT t.relname AS table_name,\n          CASE\n            WHEN t.relreplident = 'd' THEN 'default'\n            WHEN t.relreplident = 'n' THEN 'nothing'\n            WHEN t.relreplident = 'i' THEN 'index'\n            WHEN t.relreplident = 'f' THEN 'full'\n          END AS replica_identity\n    FROM pg_class t\n    JOIN pg_namespace ns ON t.relnamespace = ns.oid\n    WHERE ns.nspname = '\#{schema_name}'\n      AND t.relkind = 'r'\n      AND t.relname IN (\#{formatted_table_list})\n  SQL\n\n  results =\n    Query.run(\n      query: sql,\n      connection_url: conn_string,\n      user: db_user(conn_string),\n    )\n\n  results.all? { |r| r[:replica_identity] != \"nothing\" }\nend\n"

.user_exists?(conn_string:, user: internal_user_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_easy_replicate.rb', line 402

def user_exists?(conn_string:, user: internal_user_name)
  sql = "    SELECT r.rolname AS username,\n      r1.rolname AS \"role\"\n    FROM pg_catalog.pg_roles r\n    LEFT JOIN pg_catalog.pg_auth_members m ON (m.member = r.oid)\n    LEFT JOIN pg_roles r1 ON (m.roleid=r1.oid)\n    WHERE r.rolname = '\#{user}'\n    ORDER BY 1;\n  SQL\n\n  Query\n    .run(\n      query: sql,\n      connection_url: conn_string,\n      user: db_user(conn_string),\n    )\n    .any? { |q| q[:username] == user }\nend\n"