Merge pull request abronte#42 from takeyuweb/json_key

Support JSON Key file authentication

Author: abronte

Gemfile.lock

@@ -3,6 +3,7 @@ PATH
   specs:
     bigquery (0.9.0)
       google-api-client (= 0.9.3)
+      googleauth (>= 0.5.0)
 
 GEM
   remote: https://rubygems.org/
@@ -36,9 +37,9 @@ GEM
       signet (~> 0.7)
     httpclient (2.7.1)
     hurley (0.2)
-    jwt (1.5.3)
+    jwt (1.5.4)
     little-plugger (1.1.4)
-    logging (2.0.0)
+    logging (2.1.0)
       little-plugger (~> 1.1)
       multi_json (~> 1.10)
     memoist (0.14.0)

bigquery.gemspec

@@ -16,6 +16,7 @@ Gem::Specification.new do |s|
   s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
 
   s.add_dependency "google-api-client", "0.9.3"
+  s.add_dependency "googleauth", ">=  0.5.0"
 
   s.add_development_dependency "bundler"
   s.add_development_dependency "rake"

lib/big_query/client.rb

@@ -47,18 +47,31 @@ def initialize(opts = {})
         @client.request_options.open_timeout_sec = opts['request_option']['open_timeout_sec']
       end
 
-      begin
-        key = Google::APIClient::KeyUtils.load_from_pkcs12(opts['key'], 'notasecret')
-      rescue ArgumentError
-        key = Google::APIClient::KeyUtils.load_from_pem(opts['key'], 'notasecret')
+      scope = 'https://www.googleapis.com/auth/bigquery'
+      if opts['json_key'].is_a?(String) && !opts['json_key'].empty?
+        if File.exist?(opts['json_key'])
+          auth = File.open(opts['json_key']) do |f|
+            Google::Auth::ServiceAccountCredentials.make_creds(json_key_io: f, scope: scope)
+          end
+        else
+          key = StringIO.new(opts['json_key'])
+          auth = Google::Auth::ServiceAccountCredentials.make_creds(json_key_io: key, scope: scope)
+        end
+      else
+        begin
+          key = Google::APIClient::KeyUtils.load_from_pkcs12(opts['key'], 'notasecret')
+        rescue ArgumentError
+          key = Google::APIClient::KeyUtils.load_from_pem(opts['key'], 'notasecret')
+        end
+        auth = Signet::OAuth2::Client.new(
+            token_credential_uri: 'https://accounts.google.com/o/oauth2/token',
+            audience: 'https://accounts.google.com/o/oauth2/token',
+            scope: scope,
+            issuer: opts['service_email'],
+            signing_key: key)
       end
 
-      @client.authorization = Signet::OAuth2::Client.new(
-        token_credential_uri: 'https://accounts.google.com/o/oauth2/token',
-        audience: 'https://accounts.google.com/o/oauth2/token',
-        scope: 'https://www.googleapis.com/auth/bigquery',
-        issuer: opts['service_email'],
-        signing_key: key)
+      @client.authorization = auth
 
       refresh_auth