goose/internal/gooseutil/resolve.go

125 lines
3.6 KiB
Go

// Package gooseutil provides utility functions we want to keep internal to the package. It's
// intended to be a collection of well-tested helper functions.
package gooseutil
import (
"fmt"
"math"
"sort"
"strconv"
"strings"
)
// UpVersions returns a list of migrations to apply based on the versions in the filesystem and the
// versions in the database. The target version can be used to specify a target version. In most
// cases this will be math.MaxInt64.
//
// The allowMissing flag can be used to allow missing migrations as part of the list of migrations
// to apply. Otherwise, an error will be returned if there are missing migrations in the database.
func UpVersions(
fsysVersions []int64,
dbVersions []int64,
target int64,
allowMissing bool,
) ([]int64, error) {
// Sort the list of versions in the filesystem. This should already be sorted, but we do this
// just in case.
sortAscending(fsysVersions)
// dbAppliedVersions is a map of all applied migrations in the database.
dbAppliedVersions := make(map[int64]bool, len(dbVersions))
var dbMaxVersion int64
for _, v := range dbVersions {
dbAppliedVersions[v] = true
if v > dbMaxVersion {
dbMaxVersion = v
}
}
// Get a list of migrations that are missing from the database. A missing migration is one that
// has a version less than the max version in the database and has not been applied.
//
// In most cases the target version is math.MaxInt64, but it can be used to specify a target
// version. In which case we respect the target version and only surface migrations up to and
// including that target.
var missing []int64
for _, v := range fsysVersions {
if dbAppliedVersions[v] {
continue
}
if v < dbMaxVersion && v <= target {
missing = append(missing, v)
}
}
// feat(mf): It is very possible someone may want to apply ONLY new migrations and skip missing
// migrations entirely. At the moment this is not supported, but leaving this comment because
// that's where that logic would be handled.
//
// For example, if database has 1,4 already applied and 2,3,5 are new, we would apply only 5 and
// skip 2,3. Not sure if this is a common use case, but it's possible someone may want to do
// this.
if len(missing) > 0 && !allowMissing {
return nil, newMissingError(missing, dbMaxVersion, target)
}
var out []int64
// 1. Add missing migrations to the list of migrations to apply, if any.
out = append(out, missing...)
// 2. Add new migrations to the list of migrations to apply, if any.
for _, v := range fsysVersions {
if dbAppliedVersions[v] {
continue
}
if v > dbMaxVersion && v <= target {
out = append(out, v)
}
}
// 3. Sort the list of migrations to apply.
sortAscending(out)
return out, nil
}
func newMissingError(
missing []int64,
dbMaxVersion int64,
target int64,
) error {
sortAscending(missing)
collected := make([]string, 0, len(missing))
for _, v := range missing {
collected = append(collected, strconv.FormatInt(v, 10))
}
msg := "migration"
if len(collected) > 1 {
msg += "s"
}
var versionsMsg string
if len(collected) > 1 {
versionsMsg = "versions " + strings.Join(collected, ",")
} else {
versionsMsg = "version " + collected[0]
}
desiredMsg := fmt.Sprintf("database version (%d)", dbMaxVersion)
if target != math.MaxInt64 {
desiredMsg += fmt.Sprintf(", with target version (%d)", target)
}
return fmt.Errorf("detected %d missing (out-of-order) %s lower than %s: %s",
len(missing), msg, desiredMsg, versionsMsg,
)
}
func sortAscending(versions []int64) {
sort.Slice(versions, func(i, j int) bool {
return versions[i] < versions[j]
})
}