Merge pull request #8 from doximity/MOFONETPROFILES-135-add-routing-header-for-query-vs-write

Mofonetprofiles 135 add routing header for query vs write

Author: bsimpson

CHANGELOG.md

@@ -1,6 +1,9 @@
 Changelog
 =========
 
+## v1.0.2 07/19/2022
+* Adds an access_mode setting to cypher queries
+
 ## v1.0.1 05/24/2022
 * Expand documentation configuration settings
 

Gemfile.lock

@@ -1,16 +1,17 @@
 PATH
   remote: .
   specs:
-    neo4j-http (1.0.1)
+    neo4j-http (1.0.2)
       activesupport (>= 5.2)
       faraday (< 2)
       faraday-retry
       faraday_middleware
+      pry
 
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (7.0.3)
+    activesupport (7.0.3.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
@@ -35,20 +36,20 @@ GEM
     faraday-em_synchrony (1.0.0)
     faraday-excon (1.1.0)
     faraday-httpclient (1.0.1)
-    faraday-multipart (1.0.3)
-      multipart-post (>= 1.2, < 3)
+    faraday-multipart (1.0.4)
+      multipart-post (~> 2)
     faraday-net_http (1.0.1)
     faraday-net_http_persistent (1.2.0)
     faraday-patron (1.0.0)
     faraday-rack (1.0.0)
     faraday-retry (1.0.3)
     faraday_middleware (1.2.0)
       faraday (~> 1.0)
-    i18n (1.10.0)
+    i18n (1.12.0)
       concurrent-ruby (~> 1.0)
     method_source (1.0.0)
-    minitest (5.15.0)
-    multipart-post (2.1.1)
+    minitest (5.16.2)
+    multipart-post (2.2.3)
     parallel (1.22.1)
     parser (3.1.1.0)
       ast (~> 2.4.1)
@@ -100,7 +101,6 @@ PLATFORMS
 
 DEPENDENCIES
   neo4j-http!
-  pry
   rake (~> 12.0)
   rspec (~> 3.0)
   standard

README.md

@@ -33,6 +33,7 @@ The client is configured by default via a set of environment variables from [Neo
 * `NEO4J_DATABASE` - The database name to be used when connecting.  By default this will be `nil`.
 * `NEO4J_HTTP_USER_AGENT` - The user agent name provided in the request - defaults to `"Ruby Neo4j Http Client"`
 * `NEO4J_REQUEST_TIMEOUT_IN_SECONDS` - The number of seconds for the http request to time out if provided - defaults to `nil`
+* `ACCESS_MODE` - "WRITE", or "READ" for read only instances of Neo4j clients - defaults to `"WRITE"`
 
 These configuration values can also be set during initalization, and take precedence over the environment variables:
 
@@ -44,6 +45,7 @@ Neo4j::Http.configure do |config|
   config.database_name = nil
   config.user_agent = "Ruby Neo4j Http Client"
   config.request_timeout_in_seconds = nil
+  config.access_mode = "WRITE"
 end
 ```
 

lib/neo4j/http/configuration.rb

@@ -9,6 +9,7 @@ class Configuration
       attr_accessor :uri
       attr_accessor :user
       attr_accessor :user_agent
+      attr_accessor :access_mode
 
       def initialize(options = ENV)
         @uri = options.fetch("NEO4J_URL", "http://localhost:7474")
@@ -17,6 +18,7 @@ def initialize(options = ENV)
         @database_name = options.fetch("NEO4J_DATABASE", nil)
         @user_agent = options.fetch("NEO4J_HTTP_USER_AGENT", "Ruby Neo4j Http Client")
         @request_timeout_in_seconds = options.fetch("NEO4J_REQUEST_TIMEOUT_IN_SECONDS", nil)
+        @access_mode = options.fetch("NEO4J_ACCESS_MODE", "WRITE")
       end
 
       # https://neo4j.com/developer/manage-multiple-databases/

lib/neo4j/http/cypher_client.rb

@@ -12,33 +12,47 @@ def self.default
         @default ||= new(Neo4j::Http.config)
       end
 
-      def initialize(configuration)
+      def initialize(configuration, injected_connection = nil)
         @configuration = configuration
+        @injected_connection = injected_connection
       end
 
+      # Executes a cypher query, passing in the cypher statement, with parameters as an optional hash
+      # e.g. Neo4j::Http::Cypherclient.execute_cypher("MATCH (n { foo: $foo }) LIMIT 1 RETURN n", { foo: "bar" })
       def execute_cypher(cypher, parameters = {})
+        # By default the access mode is set to "WRITE", but can be set to "READ"
+        # for improved routing performance on read only queries
+        access_mode = parameters.delete(:access_mode) || @configuration.access_mode
+
         request_body = {
           statements: [
-            {statement: cypher,
-             parameters: parameters.as_json}
+            {
+              statement: cypher,
+              parameters: parameters.as_json
+            }
           ]
         }
 
-        response = connection.post(transaction_path, request_body)
+        @connection = @injected_connection || connection(access_mode)
+        response = @connection.post(transaction_path, request_body)
         results = check_errors!(cypher, response, parameters)
 
         Neo4j::Http::Results.parse(results&.first || {})
       end
 
-      def connection
-        build_connection
+      def connection(access_mode)
+        build_connection(access_mode)
       end
 
       protected
 
       delegate :auth_token, :transaction_path, to: :@configuration
       def check_errors!(cypher, response, parameters)
         raise Neo4j::Http::Errors::InvalidConnectionUrl, response.status if response.status == 404
+        if response.body["errors"].any? { |error| error["message"][/Routing WRITE queries is not supported/] }
+          raise Neo4j::Http::Errors::ReadOnlyError
+        end
+
         body = response.body || {}
         errors = body.fetch("errors", [])
         return body.fetch("results", {}) unless errors.present?
@@ -61,8 +75,10 @@ def find_error_class(code)
         Neo4j::Http::Errors::Neo4jCodedError
       end
 
-      def build_connection
-        Faraday.new(url: @configuration.uri, headers: build_http_headers, request: build_request_options) do |f|
+      def build_connection(access_mode)
+        # https://neo4j.com/docs/http-api/current/actions/transaction-configuration/
+        headers = build_http_headers.merge({"access-mode" => access_mode})
+        Faraday.new(url: @configuration.uri, headers: headers, request: build_request_options) do |f|
           f.request :json # encode req bodies as JSON
           f.request :retry # retry transient failures
           f.response :json # decode response bodies as JSON

lib/neo4j/http/errors.rb

@@ -4,6 +4,7 @@ module Errors
       Neo4jError = Class.new(StandardError)
       InvalidConnectionUrl = Class.new(Neo4jError)
       Neo4jCodedError = Class.new(Neo4jError)
+      ReadOnlyError = Class.new(Neo4jError)
 
       # These are specific Errors Neo4j can raise
       module Neo

lib/neo4j/http/node_client.rb

@@ -41,15 +41,16 @@ def delete_node(node)
       def find_node_by(label:, **attributes)
         selectors = attributes.map { |key, value| "#{key}: $attributes.#{key}" }.join(", ")
         cypher = "MATCH (node:#{label} { #{selectors} }) RETURN node LIMIT 1"
-        results = @cypher_client.execute_cypher(cypher, attributes: attributes)
+        results = @cypher_client.execute_cypher(cypher, attributes: attributes.merge(access_mode: "READ"))
         return if results.empty?
+
         results.first&.fetch("node")
       end
 
       def find_nodes_by(label:, attributes:, limit: 100)
         selectors = build_selectors(attributes)
         cypher = "MATCH (node:#{label}) where #{selectors} RETURN node LIMIT #{limit}"
-        results = @cypher_client.execute_cypher(cypher, attributes: attributes)
+        results = @cypher_client.execute_cypher(cypher, attributes: attributes.merge(access_mode: "READ"))
         results.map { |result| result["node"] }
       end
 

lib/neo4j/http/relationship_client.rb

@@ -52,7 +52,13 @@ def find_relationship(from:, relationship:, to:)
           RETURN from, to, relationship
         CYPHER
 
-        results = @cypher_client.execute_cypher(cypher, from: from, to: to, relationship: relationship)
+        results = @cypher_client.execute_cypher(
+          cypher,
+          from: from,
+          to: to,
+          relationship: relationship,
+          access_mode: "READ"
+        )
         results&.first
       end
 

lib/neo4j/http/results.rb

@@ -4,7 +4,10 @@ module Neo4j
   module Http
     class Results
       # Example result set:
-      # [{"columns"=>["n"], "data"=>[{"row"=>[{"name"=>"Foo", "uuid"=>"8c7dcfda-d848-4937-a91a-2e6debad2dd6"}], "meta"=>[{"id"=>242, "type"=>"node", "deleted"=>false}]}]}]
+      # [{"columns"=>["n"],
+      # "data"=>
+      # [{"row"=>[{"name"=>"Foo", "uuid"=>"8c7dcfda-d848-4937-a91a-2e6debad2dd6"}],
+      #   "meta"=>[{"id"=>242, "type"=>"node", "deleted"=>false}]}]}]
       #
       def self.parse(results)
         columns = results["columns"]

lib/neo4j/http/version.rb

@@ -1,5 +1,5 @@
 module Neo4j
   module Http
-    VERSION = "1.0.1"
+    VERSION = "1.0.2"
   end
 end