Added minimal support for data migrations.

README.textile

@@ -1,5 +1,7 @@
 h3. What's New?
 
+* 2009-05-27
+** Added minimal support for data migrations. Although CouchDB's nature removes the necessity for migrations, certain knowledge that all objects possess a particular property can simplify client logic. This desire for simplification is the rationale behind this change.
 * 2009-04-19 
 ** Defaults to taf2-curb, falling back to Net/HTTP if it taf2-curb can't be loaded. Thanks to "Fred Cheung":http://www.spacevatican.org/2009/4/13/fun-with-ruby-http-clients.
 ** For those interested in using RelaxDB with an ETag based cache, "look here":http://github.com/fcheung/relaxdb/commit/1d9acfd5f6b3c23da0d275252b6a6e064865440e
@@ -171,6 +173,20 @@ h3. Creating views by hand
 </code>
 </pre>
 
+h3. Migrations
+
+<pre>
+<code>
+  $ cat 001_double.rb
+  RelaxDB::Migration.run Primitives do |p| 
+    p.num *= 2 
+    p
+  end
+
+  $ ruby -e 'RelaxDB::Migration.run_all Dir["./*.rb"]'
+</code>
+</pre>
+
 h3. Visualise
 
 "Fuschia":http://github.com/paulcarey/fuschia/tree/master offers a web front end for visualising inter-document relationships.

Rakefile

@@ -4,7 +4,7 @@ require 'spec/rake/spectask'
 
 PLUGIN = "relaxdb"
 NAME = "relaxdb"
-GEM_VERSION = "0.3.2"
+GEM_VERSION = "0.3.3"
 AUTHOR = "Paul Carey"
 EMAIL = "paul.p.carey@gmail.com"
 HOMEPAGE = "http://github.com/paulcarey/relaxdb/"

lib/relaxdb.rb

@@ -30,6 +30,7 @@
 require 'relaxdb/extlib'
 require 'relaxdb/has_many_proxy'
 require 'relaxdb/has_one_proxy'
+require 'relaxdb/migration'
 require 'relaxdb/paginate_params'
 require 'relaxdb/paginator'
 require 'relaxdb/query'
@@ -43,5 +44,7 @@
 require 'relaxdb/views'
 require 'more/grapher.rb'
 
+require 'relaxdb/migration_version'
+
 module RelaxDB
 end

lib/relaxdb/migration.rb

@@ -0,0 +1,40 @@
+module RelaxDB
+
+  class Migration
+
+    def self.run klass, limit = 1000
+      query = lambda do |page_params|
+        RelaxDB.paginate_view "#{klass}_all", :startkey => nil, :endkey => {}, :attributes => [:_id],
+          :page_params => page_params, :limit => limit
+      end
+
+      objs = query.call({})
+      until objs.empty?
+        migrated = objs.map { |o| yield o }.flatten.reject { |o| o.nil? }
+        RelaxDB.bulk_save! *migrated
+        objs = objs.next_params ? query.call(objs.next_params) : []
+      end
+    end
+
+    #
+    # Runs all outstanding migrations in a given directory
+    #
+    # ==== Example
+    #   RelaxDB::Migration.run_all Dir["couchdb/migrations/**/*.rb"]
+    #
+    def self.run_all file_names, action = lambda { |fn| require fn }
+      v = RelaxDB::MigrationVersion.version
+      file_names.select { |fn| fv(fn) > v }.each do |fn|
+        RelaxDB.logger.info "Applying #{fn}"
+        action.call fn
+        RelaxDB::MigrationVersion.update fv(fn)
+      end
+    end
+
+    def self.fv file_name
+      File.basename(file_name).split("_")[0].to_i
+    end
+
+  end
+
+end

lib/relaxdb/migration_version.rb

@@ -0,0 +1,21 @@
+class RelaxDB::MigrationVersion < RelaxDB::Document
+
+  DOC_ID = "relaxdb_migration_version"
+
+  property :version, :default => 0
+
+  def self.version
+    retrieve.version
+  end
+
+  def self.update v
+    mv = retrieve
+    mv.version = v
+    mv.save!
+  end
+
+  def self.retrieve
+    (v = RelaxDB.load(DOC_ID)) ? v : new(:_id => DOC_ID).save!
+  end
+
+end

lib/relaxdb/relaxdb.rb

@@ -73,7 +73,7 @@ def bulk_save!(*objs)
       end
 
       pre_save_success = objs.inject(true) { |s, o| s &= o.pre_save }
-      raise ValidationFailure, objs unless pre_save_success
+      raise ValidationFailure, objs.inspect unless pre_save_success
 
       docs = {}
       objs.each { |o| docs[o._id] = o }

lib/relaxdb/views.rb

@@ -8,7 +8,7 @@ def self.all(kls)
       function(doc) {        
         var class_match = #{kls_check kls}
         if (class_match) {
-          emit(null, doc);
+          emit(doc._id, doc);
         }
       }
       QUERY

relaxdb.gemspec

@@ -1,7 +1,10 @@
+# Updating the gemspec
+#   ruby -e 'Dir["spec/*"].each { |fn| puts "\"#{fn}\," }'
+
 Gem::Specification.new do |s|
   s.name = "relaxdb"
-  s.version = "0.3.2"
-  s.date = "2009-05-22"
+  s.version = "0.3.3"
+  s.date = "2009-05-27"
   s.summary = "RelaxDB provides a simple interface to CouchDB"
   s.email = "paul.p.carey@gmail.com"
   s.homepage = "http://github.com/paulcarey/relaxdb/"
@@ -21,6 +24,8 @@ Gem::Specification.new do |s|
    "lib/relaxdb/has_many_proxy.rb",
    "lib/relaxdb/has_one_proxy.rb",
    "lib/relaxdb/net_http_server.rb",
+   "lib/relaxdb/migration.rb",
+   "lib/relaxdb/migration_version.rb",
    "lib/relaxdb/paginate_params.rb",
    "lib/relaxdb/paginator.rb",
    "lib/relaxdb/query.rb",
@@ -39,18 +44,26 @@ Gem::Specification.new do |s|
    "lib/more/atomic_bulk_save_support.rb",
    "spec/belongs_to_spec.rb",
    "spec/callbacks_spec.rb",
-   "spec/design_doc_spec.rb",
    "spec/derived_properties_spec.rb",
+   "spec/design_doc_spec.rb",
+   "spec/doc_inheritable_spec.rb",
    "spec/document_spec.rb",
    "spec/has_many_spec.rb",
    "spec/has_one_spec.rb",
+   "spec/migration_spec.rb",
+   "spec/migration_version_spec.rb",
+   "spec/paginate_params_spec.rb",
+   "spec/paginate_spec.rb",
    "spec/query_spec.rb",
    "spec/references_many_spec.rb",
    "spec/relaxdb_spec.rb",
+   "spec/server_spec.rb",
    "spec/spec.opts",
    "spec/spec_helper.rb",
    "spec/spec_models.rb",
-   "spec/view_object_spec.rb"]
+   "spec/view_by_spec.rb",
+   "spec/view_object_spec.rb",
+   "spec/view_spec.rb"]
   s.bindir = "bin"
   s.autorequire = "relaxdb"
   s.add_dependency "extlib", ">= 0.9.4" # removed ", runtime" as was failing locally

spec/migration_spec.rb

@@ -0,0 +1,97 @@
+require File.join(File.dirname(__FILE__), "spec_helper")
+require File.join(File.dirname(__FILE__), "spec_models")
+
+describe RelaxDB::Migration do
+
+  before(:each) do
+    @mig = RelaxDB::Migration
+    setup_test_db
+  end
+
+  it "should yield each obj to the block and save the result" do
+    Primitives.new(:num => 5).save!
+    r = @mig.run Primitives do |p|
+      pn = Primitives.new(:num => p.num * 2)
+      [p, pn]
+    end
+    Primitives.by_num.map { |p| p.num}.should == [5, 10]
+  end
+
+  it "should raise an exception if a save results in a conflict" do
+    op = Primitives.new.save!
+    lambda do 
+      @mig.run Primitives do |p|
+        op.save!
+        p
+      end
+    end.should raise_error(RelaxDB::UpdateConflict)
+  end
+
+  it "should not save docs for blocks that return nil" do
+    Primitives.new.save!
+    @mig.run Primitives do |p| 
+      nil
+    end
+  end
+
+  describe "multiple docs" do
+
+    before(:each) do
+      ps = (1..5).map { |i| Primitives.new :num => i }
+      RelaxDB.bulk_save *ps
+      RelaxDB.db.reset_req_count
+    end
+
+    # Note: two extra requests per paginate_view request are required
+    it "should operate on a doc set of the given size aka limit" do
+      @mig.run(Primitives, 1) { |p| p.num *= p.num; p }
+      RelaxDB.db.req_count.should == 10 + 5 * 2 
+      Primitives.by_num.map { |p| p.num }.should == [1, 4, 9, 16, 25]      
+    end
+
+    it "should operate on a doc set of default size" do
+      @mig.run(Primitives) { |p| p.num *= p.num; p }
+      RelaxDB.db.req_count.should == 2 + 1 * 2
+      Primitives.by_num.map { |p| p.num }.should == [1, 4, 9, 16, 25]      
+    end
+
+  end
+
+  describe "#fv" do
+    it "should return valid numbers" do
+      @mig.fv("foo/bar/001_foo.rb").should == 1 
+    end
+  end
+
+  describe ".run_all" do
+
+    it "should save the version after each successful migration" do
+      @mig.run_all "a/b/1_", lambda {}
+      RelaxDB::MigrationVersion.version.should == 1
+    end
+
+    it "should not run those migrations whose version is less than the current version" do
+      v = RelaxDB::MigrationVersion.retrieve
+      v.version = 2
+      v.save!
+      @mig.run_all "3_", lambda {}
+      RelaxDB::MigrationVersion.version.should == 3
+    end
+
+    it "should run those migrations whose version is greater than the current version" do
+      v = RelaxDB::MigrationVersion.retrieve
+      v.version = 2
+      v.save!
+      @mig.run_all "1_foo", lambda {}
+      RelaxDB::MigrationVersion.version.should == 2
+    end
+
+    it "should raise an exception on failure" do
+      lambda do
+        @mig.run_all "1_foo", lambda { raise "Expected" }
+      end.should raise_error(RuntimeError, "Expected")
+    end
+
+  end
+
+end

spec/migration_version_spec.rb

@@ -0,0 +1,28 @@
+require File.join(File.dirname(__FILE__), "spec_helper")
+require File.join(File.dirname(__FILE__), "spec_models")
+
+describe RelaxDB::MigrationVersion do
+
+  before(:each) do
+    setup_test_db
+  end
+
+  it "should not exist in a clean db" do
+    RelaxDB.load(RelaxDB::MigrationVersion::DOC_ID).should be_nil
+  end
+
+  it "should return zero when it doesnt exist" do
+    RelaxDB::MigrationVersion.version.should == 0
+  end
+
+  it "should autosave on retrieval when when it doesnt exist" do
+    RelaxDB::MigrationVersion.version
+    RelaxDB.load(RelaxDB::MigrationVersion::DOC_ID).should be
+  end
+
+  it "should return the saved version" do
+    RelaxDB::MigrationVersion.update 10
+    RelaxDB::MigrationVersion.version.should == 10
+  end
+
+end

spec/relaxdb_spec.rb

@@ -39,11 +39,7 @@
       ta.should == t1
       tb.should == t2
     end
-
-    it "should succeed when passed no args" do
-      RelaxDB.bulk_save
-    end
-
+
     it "should return false on failure" do
       c = Class.new(RelaxDB::Document) do
         property :foo, :validator => lambda { false }
@@ -128,6 +124,16 @@
 
   describe ".bulk_save!" do
 
+    it "should succeed when passed no args" do
+      RelaxDB.bulk_save!
+    end
+
+    it "should raise when passed a nil value" do
+      lambda do
+        RelaxDB.bulk_save! *[nil]
+      end.should raise_error
+    end
+
     it "should raise an exception if a obj fails validation" do
       c = Class.new(RelaxDB::Document) do
         property :foo, :validator => lambda { false }

spec/spec_helper.rb

@@ -9,8 +9,12 @@
 $:.unshift(File.dirname(__FILE__) + '/../lib')
 require 'relaxdb'
 
+class RdbFormatter; def call(sv, time, progname, msg); puts msg; end; end
+
 def setup_test_db
   # RelaxDB.configure :host => "localhost", :port => 5984, :design_doc => "spec_doc", :logger => Logger.new(STDOUT)
+  # RelaxDB.logger.formatter = RdbFormatter.new
+
   RelaxDB.configure :host => "localhost", :port => 5984, :design_doc => "spec_doc"
 
   RelaxDB.delete_db "relaxdb_spec" rescue "ok"