Class: Parse::Schema::IndexMigrator

Inherits:
Object
  • Object
show all
Defined in:
lib/parse/schema/index_migrator.rb

Overview

Reconciliation engine for ‘Parse::Core::Indexing` declarations vs. the actual MongoDB index state. Reads existing indexes via the reader connection (so `plan` works in dry-run mode without writer config); applies via the writer connection through MongoDB.create_index / MongoDB.drop_index (which re-check the triple gate and run their own per-call idempotency check on the writer-side index list).

Multi-collection. A single model can declare indexes against both its own collection (via ‘mongo_index`) and one or more `_Join:<field>:<ParentClass>` collections (via `mongo_relation_index`). `plan` returns a Hash keyed by collection name with one entry per unique target collection across the declaration list. `apply!` returns a similarly-keyed result Hash.

Parse-managed indexes (the ones Parse Server auto-creates on collections like ‘_User`, `_Session`, `_Role`) are never proposed for drop, regardless of whether they appear in the declaration list. The list is conservative — any name matching PARSE_MANAGED_INDEX_PATTERNS is treated as off-limits to the migrator, full stop.

Constant Summary collapse

PARSE_MANAGED_INDEX_PATTERNS =

Names / patterns of indexes Parse Server creates and owns. The migrator excludes these from both ‘to_drop` (so a missing declaration never proposes their removal) and from `in_sync` (so they don’t visually clutter operator review). They appear in ‘parse_managed:` for transparency.

**Coverage is not forward-compatible.** This list reflects the indexes Parse Server auto-creates as of Parse Server 7.x. Any future Parse Server release that adds a new managed index will cause that index to be classified as an orphan and be eligible for drop under ‘DROP=true`. Operators upgrading Parse Server should re-review this list before re-running `parse:mongo:indexes:apply` with the drop flag.

Any non-declared, non-managed index — including DBA-created diagnostic indexes, indexes created by other Parse SDKs, and MongoDB Atlas index recommendations — is also classified as an orphan. If you need to preserve such an index, declare it via Core::Indexing#mongo_index on the model.

[
  /\A_id_\z/,
  /\A_username_unique\z/,
  /\A_email_unique\z/,
  /\Aemail_1\z/,
  /\Ausername_1\z/,
  /\A_session_token_/,
  /\A_email_verify_token_/,
  /\A_perishable_token_/,
  /\A_account_lockout_/,
  /\Acase_insensitive_/,
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model_class) ⇒ IndexMigrator

Returns a new instance of IndexMigrator.



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# File 'lib/parse/schema/index_migrator.rb', line 62

def initialize(model_class)
  unless model_class.is_a?(Class) && model_class < Parse::Object
    raise ArgumentError, "IndexMigrator expects a Parse::Object subclass; got #{model_class.inspect}"
  end
  @model_class = model_class
end

Instance Attribute Details

#model_class ⇒ Object (readonly)

Returns the value of attribute model_class.



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# File 'lib/parse/schema/index_migrator.rb', line 60

def model_class
  @model_class
end

Instance Method Details

#apply!(drop: false) ⇒ Hash{String => Hash}

Apply the plan across all target collections. Additive by default; ‘drop: true` opts into orphan removal on every target. Each drop carries its own confirmation envelope through `Parse::MongoDB.drop_index`.

Returns:

  • (Hash{String => Hash}) —

    keyed by collection name. Each value Hash mirrors the legacy single-collection apply shape: ‘{ created:, skipped_exists:, dropped:, conflicts:, capacity_blocked: }`.



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# File 'lib/parse/schema/index_migrator.rb', line 151

def apply!(drop: false)
  target_collections.each_with_object({}) do |coll, h|
    h[coll] = apply_for!(coll, drop: drop)
  end
end

#apply_for!(collection, drop: false) ⇒ Object

Per-collection apply. Honors the same triple-gate / idempotency rules as the cross-collection ‘apply!`. When `drop: true` the method runs orphan drops BEFORE create_index so freed index slots are available to satisfy `to_create` — required when the collection is at or near the 64-index cap. Capacity is checked against the post-drop count, matching the actual mid-apply state.



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# File 'lib/parse/schema/index_migrator.rb', line 164

def apply_for!(collection, drop: false)
  p = plan_for(collection)
  capacity_ok = drop ? p[:capacity_ok_with_drop] : p[:capacity_ok]
  return { created: [], skipped_exists: [], dropped: [], conflicts: p[:conflicts],
           capacity_blocked: true } unless capacity_ok

  created = []
  # Pre-seed skipped_exists with the declarations the plan already
  # classified as in_sync — they don't go through create_index, but
  # callers expect the result to reflect EVERY declaration's fate.
  skipped = p[:in_sync].dup
  dropped = []

  # Drops run BEFORE creates so a full collection with one orphan
  # and one new declaration doesn't hit "too many indexes" before
  # the drop frees a slot.
  if drop
    p[:orphans].each do |name|
      confirm = "drop:#{collection}:#{name}"
      res = Parse::MongoDB.drop_index(collection, name, confirm: confirm,
                                      allow_system_classes: collection.start_with?("_Join:"))
      dropped << name if res == :dropped
    end
  end

  p[:to_create].each do |decl|
    result = Parse::MongoDB.create_index(
      collection,
      decl[:keys],
      name:                decl[:options][:name],
      unique:              decl[:options][:unique] == true,
      sparse:              decl[:options][:sparse] == true,
      partial_filter:      decl[:options][:partial_filter],
      expire_after:        decl[:options][:expire_after],
      allow_system_classes: collection.start_with?("_Join:"),
    )
    (result == :exists ? skipped : created) << decl
  end

  {
    created:        created,
    skipped_exists: skipped,
    dropped:        dropped,
    conflicts:      p[:conflicts],
    capacity_blocked: false,
  }
end

#collection_name ⇒ String

Returns the model’s primary collection name (parse_class).

Returns:

  • (String) —

    the model’s primary collection name (parse_class).



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# File 'lib/parse/schema/index_migrator.rb', line 70

def collection_name
  @model_class.parse_class
end

#plan ⇒ Hash{String => Hash}

Compute the plan: what would change if ‘apply!` ran now.

Returns:

  • (Hash{String => Hash}) —

    keyed by collection name. Each value Hash carries the per-collection result (see #plan_for).



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# File 'lib/parse/schema/index_migrator.rb', line 86

def plan
  target_collections.each_with_object({}) do |coll, h|
    h[coll] = plan_for(coll)
  end
end

#plan_for(collection) ⇒ Hash

Per-collection plan. Filters declarations to those targeting ‘collection`, then runs the diff against the actual MongoDB state for that collection.

Capacity accounting reports two scenarios so callers can reason about both apply modes from a single plan:

- `:capacity_after`, `:capacity_ok` — additive-only mode
  (no drops). Equal to `used + to_create.size`.
- `:capacity_after_with_drop`, `:capacity_ok_with_drop` —
  additive + orphan removal. Equal to `used + to_create.size
  - orphans.size`. Use these when planning an `apply!(drop:
  true)` call.

Parameters:

  • collection (String) —

    target collection name

Returns:

  • (Hash) —

    per-collection plan



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# File 'lib/parse/schema/index_migrator.rb', line 107

def plan_for(collection)
  existing = fetch_existing_indexes(collection)
  declared = declarations_for(collection)
  managed, ours = partition_parse_managed(existing)
  to_create, in_sync, conflicts = diff_declarations(declared, ours)
  declared_names = declared.map { |d| d[:options][:name] }.compact.to_set
  declared_sigs  = declared.map { |d| key_sig(d[:keys]) }.to_set
  orphans = ours.reject do |idx|
    declared_sigs.include?(key_sig(idx["key"] || idx[:key])) ||
      declared_names.include?(idx["name"] || idx[:name])
  end

  max = Parse::Core::Indexing::MAX_INDEXES_PER_COLLECTION
  used = existing.size
  after_no_drop = used + to_create.size
  after_with_drop = after_no_drop - orphans.size

  {
    collection:               collection,
    declared:                 declared,
    existing:                 existing,
    parse_managed:            managed.map { |i| i["name"] || i[:name] },
    to_create:                to_create,
    in_sync:                  in_sync,
    conflicts:                conflicts,
    orphans:                  orphans.map { |i| i["name"] || i[:name] }.compact,
    capacity_used:            used,
    capacity_after:           after_no_drop,
    capacity_remaining:       max - after_no_drop,
    capacity_ok:              after_no_drop <= max,
    capacity_after_with_drop: after_with_drop,
    capacity_remaining_with_drop: max - after_with_drop,
    capacity_ok_with_drop:    after_with_drop <= max,
  }
end

#target_collections ⇒ Array<String>

Returns unique target collections across all declarations. Includes the parent collection only when at least one declaration targets it (i.e. a non-relation index).

Returns:

  • (Array<String>) —

    unique target collections across all declarations. Includes the parent collection only when at least one declaration targets it (i.e. a non-relation index).



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# File 'lib/parse/schema/index_migrator.rb', line 77

def target_collections
  @model_class.mongo_index_declarations.map { |d| d[:collection] || collection_name }.uniq
end