cmd_init.go

package main

import (
	"fmt"
	"os"
	"path"
	"strconv"
	"strings"

	log "github.com/sirupsen/logrus"
	"github.com/skeema/mybase"
	"github.com/skeema/skeema/dumper"
	"github.com/skeema/skeema/fs"
	"github.com/skeema/tengo"
)

func init() {
	summary := "Save a DB instance's schemas and tables to the filesystem"
	desc := `Creates a filesystem representation of the schemas and tables on a db instance.
For each schema on the instance (or just the single schema specified by
--schema), a subdir with a .skeema config file will be created. Each directory
will be populated with .sql files containing CREATE TABLE statements for every
table in the schema.

You may optionally pass an environment name as a CLI option. This will affect
which section of .skeema config files the host and schema names are written to.
For example, running ` + "`" + `skeema init staging` + "`" + ` will add config directives to the
[staging] section of config files. If no environment name is supplied, the
default is "production", so directives will be written to the [production]
section of the file.`

	cmd := mybase.NewCommand("init", summary, desc, InitHandler)
	cmd.AddOption(mybase.StringOption("host", 'h', "", "Database hostname or IP address"))
	cmd.AddOption(mybase.StringOption("port", 'P', "3306", "Port to use for database host"))
	cmd.AddOption(mybase.StringOption("socket", 'S', "/tmp/mysql.sock", "Absolute path to Unix socket file used if host is localhost"))
	cmd.AddOption(mybase.StringOption("dir", 'd', "<hostname>", "Subdir name to use for this host's schemas"))
	cmd.AddOption(mybase.StringOption("schema", 0, "", "Only import the one specified schema; skip creation of subdirs for each schema"))
	cmd.AddOption(mybase.BoolOption("include-auto-inc", 0, false, "Include starting auto-inc values in table files"))
	cmd.AddOption(mybase.StringOption("ignore-schema", 0, "", "Ignore schemas that match regex"))
	cmd.AddOption(mybase.StringOption("ignore-table", 0, "", "Ignore tables that match regex"))
	cmd.AddArg("environment", "production", false)
	CommandSuite.AddSubCommand(cmd)
}

// InitHandler is the handler method for `skeema init`
func InitHandler(cfg *mybase.Config) error {
	// Ordinarily, we use a dir structure of: host_dir/schema_name/*.sql
	// However, if --schema option used, we're only importing one schema and the
	// schema_name level is skipped.
	onlySchema := cfg.Get("schema")
	if isSystemSchema(onlySchema) {
		return NewExitValue(CodeBadConfig, "Option --schema may not be set to a system database name")
	}
	separateSchemaSubdir := (onlySchema == "")

	environment := cfg.Get("environment")
	if environment == "" || strings.ContainsAny(environment, "[]\n\r") {
		return NewExitValue(CodeBadConfig, "Environment name \"%s\" is invalid", environment)
	}

	hostDir, err := createHostDir(cfg)
	if err != nil {
		return err
	}

	// Validate connection-related options (host, port, socket, user, password) by
	// testing connection. This is done before writing an option file, so that the
	// dir may still be re-used after correcting any problems in CLI options
	inst, err := hostDir.FirstInstance()
	if err != nil {
		return err
	} else if inst == nil {
		return NewExitValue(CodeBadConfig, "Command line did not specify which instance to connect to")
	}

	// Build list of schemas
	schemaNameFilter := []string{}
	if onlySchema != "" {
		schemaNameFilter = []string{onlySchema}
	}
	schemas, err := inst.Schemas(schemaNameFilter...)
	if err != nil {
		return NewExitValue(CodeFatalError, "Cannot examine schemas on %s: %s", inst, err)
	}
	if onlySchema != "" && len(schemas) == 0 {
		return NewExitValue(CodeBadConfig, "Schema %s does not exist on instance %s", onlySchema, inst)
	}

	// Write host option file
	err = createHostOptionFile(cfg, hostDir, inst, schemas)
	if err != nil {
		return err
	}

	// Iterate over the schemas. For each one, create a dir with .skeema and *.sql files
	for _, s := range schemas {
		if err := PopulateSchemaDir(s, hostDir, separateSchemaSubdir); err != nil {
			return err
		}
	}

	return nil
}

func isSystemSchema(name string) bool {
	systemSchemas := map[string]bool{
		"mysql":              true,
		"information_schema": true,
		"performance_schema": true,
		"sys":                true,
	}
	return systemSchemas[name]
}

func createHostDir(cfg *mybase.Config) (*fs.Dir, error) {
	if !cfg.OnCLI("host") {
		return nil, NewExitValue(CodeBadConfig, "Option --host must be supplied on the command-line")
	}
	hostDirName := cfg.Get("dir")
	if !cfg.Changed("dir") { // default for dir is to base it on the hostname
		port := cfg.GetIntOrDefault("port")
		if port > 0 && cfg.Changed("port") {
			hostDirName = fmt.Sprintf("%s:%d", cfg.Get("host"), port)
		} else {
			hostDirName = cfg.Get("host")
		}
	}

	dir, err := fs.ParseDir(".", cfg)
	if err != nil {
		return nil, err
	}
	hostDir, err := dir.CreateSubdir(hostDirName, nil) // nil because we'll set up the option file later
	if err != nil {
		return nil, NewExitValue(CodeBadConfig, err.Error())
	}
	return hostDir, nil
}

func createHostOptionFile(cfg *mybase.Config, hostDir *fs.Dir, inst *tengo.Instance, schemas []*tengo.Schema) error {
	environment := cfg.Get("environment")
	hostOptionFile := mybase.NewFile(hostDir.Path, ".skeema")
	hostOptionFile.SetOptionValue(environment, "host", inst.Host)
	if inst.Host == "localhost" && inst.SocketPath != "" {
		hostOptionFile.SetOptionValue(environment, "socket", inst.SocketPath)
	} else {
		hostOptionFile.SetOptionValue(environment, "port", strconv.Itoa(inst.Port))
	}
	if flavor := inst.Flavor(); !flavor.Known() {
		log.Warnf("Unable to automatically determine database vendor/version. To set manually, use the \"flavor\" option in %s", hostOptionFile)
	} else {
		hostOptionFile.SetOptionValue(environment, "flavor", flavor.String())
	}
	for _, persistOpt := range []string{"user", "ignore-schema", "ignore-table", "connect-options"} {
		if cfg.OnCLI(persistOpt) {
			hostOptionFile.SetOptionValue(environment, persistOpt, cfg.Get(persistOpt))
		}
	}

	// If a schema name was supplied, a "flat" dir is created that represents both
	// the host and the schema. The schema name is placed outside of any named
	// section/environment since the default assumption is that schema names match
	// between environments.
	if cfg.Changed("schema") {
		hostOptionFile.SetOptionValue("", "schema", cfg.Get("schema"))
		hostOptionFile.SetOptionValue("", "default-character-set", schemas[0].CharSet)
		hostOptionFile.SetOptionValue("", "default-collation", schemas[0].Collation)
	}

	// By default, Skeema normally connects using strict sql_mode as well as
	// innodb_strict_mode=1; see InstanceDefaultParams() in fs/dir.go. If existing
	// tables aren't recreatable with those settings though, disable them.
	var nonStrictWarning string
	if !cfg.OnCLI("connect-options") {
		if compliant, err := inst.StrictModeCompliant(schemas); err == nil && !compliant {
			nonStrictWarning = fmt.Sprintf("Detected some tables are incompatible with strict-mode; setting relaxed connect-options in %s\n", hostOptionFile)
			hostOptionFile.SetOptionValue(environment, "connect-options", "innodb_strict_mode=0,sql_mode='ONLY_FULL_GROUP_BY,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION'")
		}
	}

	// Write the option file
	if err := hostDir.CreateOptionFile(hostOptionFile); err != nil {
		return NewExitValue(CodeCantCreate, "Unable to use directory %s: Unable to write to %s: %s", hostDir.Path, hostOptionFile.Path(), err)
	}

	var suffix string
	if cfg.Changed("schema") {
		suffix = "; skipping schema-level subdirs"
	}
	if nonStrictWarning == "" {
		suffix += "\n"
	}
	log.Infof("Using host dir %s for %s%s", hostDir.Path, inst, suffix)
	if nonStrictWarning != "" {
		log.Warn(nonStrictWarning)
	}
	return nil
}

// PopulateSchemaDir writes out *.sql files for all tables in the specified
// schema. If makeSubdir==true, a subdir with name matching the schema name
// will be created, and a .skeema option file will be created. Otherwise, the
// *.sql files will be put in parentDir, and it will be the caller's
// responsibility to ensure its .skeema option file exists and maps to the
// correct schema name.
func PopulateSchemaDir(s *tengo.Schema, parentDir *fs.Dir, makeSubdir bool) error {
	// Ignore any attempt to populate a dir for the temp schema
	if s.Name == parentDir.Config.Get("temp-schema") {
		return nil
	}

	if ignoreSchema, err := parentDir.Config.GetRegexp("ignore-schema"); err != nil {
		return NewExitValue(CodeBadConfig, err.Error())
	} else if ignoreSchema != nil && ignoreSchema.MatchString(s.Name) {
		log.Debugf("Skipping schema %s because ignore-schema='%s'", s.Name, ignoreSchema)
		return nil
	}

	var dir *fs.Dir
	var err error
	if makeSubdir {
		optionFile := mybase.NewFile(path.Join(parentDir.Path, s.Name), ".skeema")
		optionFile.SetOptionValue("", "schema", s.Name)
		optionFile.SetOptionValue("", "default-character-set", s.CharSet)
		optionFile.SetOptionValue("", "default-collation", s.Collation)
		dir, err = parentDir.CreateSubdir(s.Name, optionFile)
		if err != nil {
			return NewExitValue(CodeCantCreate, "Unable to create subdirectory for schema %s: %s", s.Name, err)
		}
	} else {
		dir = parentDir
	}
	log.Infof("Populating %s", dir)

	dumpOpts := dumper.Options{
		IncludeAutoInc: dir.Config.GetBool("include-auto-inc"),
	}
	dumpOpts.IgnoreTable, err = dir.Config.GetRegexp("ignore-table")
	if err != nil {
		return NewExitValue(CodeBadConfig, err.Error())
	}

	if _, err = dumper.DumpSchema(s, dir, dumpOpts); err != nil {
		return NewExitValue(CodeCantCreate, "Unable to write in %s: %s", dir, err)
	}
	os.Stderr.WriteString("\n")
	return nil
}