Use the deployed protoc spec in samples and README

Author: jcanizales

examples/objective-c/auth_sample/AuthTestService.podspec

@@ -13,20 +13,20 @@ Pod::Spec.new do |s|
   # Base directory where the .proto files are.
   src = "../../protos"
 
-  # Directory where the generated files will be placed.
-  dir = "Pods/" + s.name
-
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
   s.dependency "!ProtoCompiler-gRPCPlugin", "~> 0.14"
 
-  repo_root = '../../..'
-  pods_root = "#{repo_root}/examples/objective-c/auth_sample/Pods"
+  # Pods directory corresponding to this app's Podfile, relative to the location of this podspec.
+  pods_root = './Pods'
 
+  # Path where Cocoapods downloads protoc and the gRPC plugin.
   protoc_dir = "#{pods_root}/!ProtoCompiler"
   protoc = "#{protoc_dir}/protoc"
-
   plugin = "#{pods_root}/!ProtoCompiler-gRPCPlugin/grpc_objective_c_plugin"
 
+  # Directory where the generated files will be placed.
+  dir = "#{pods_root}/#{s.name}"
+
   s.prepare_command = <<-CMD
     mkdir -p #{dir}
     #{protoc} \
@@ -38,21 +38,25 @@ Pod::Spec.new do |s|
         #{src}/auth_sample.proto
   CMD
 
+  # Files generated by protoc
   s.subspec "Messages" do |ms|
     ms.source_files = "#{dir}/*.pbobjc.{h,m}", "#{dir}/**/*.pbobjc.{h,m}"
     ms.header_mappings_dir = dir
     ms.requires_arc = false
+    # The generated files depend on the protobuf runtime.
     ms.dependency "Protobuf"
     # This is needed by all pods that depend on Protobuf:
     ms.pod_target_xcconfig = {
       'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
     }
   end
 
+  # Files generated by the gRPC plugin
   s.subspec "Services" do |ss|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
+    # The generated files depend on the gRPC runtime, and on the files generated by protoc.
     ss.dependency "gRPC-ProtoRPC"
     ss.dependency "#{s.name}/Messages"
   end

examples/objective-c/auth_sample/Podfile

@@ -3,16 +3,10 @@ platform :ios, '8.0'
 
 install! 'cocoapods', :deterministic_uuids => false
 
-# Location of gRPC's repo root relative to this file.
-GRPC_LOCAL_SRC = '../../..'
-
 target 'AuthSample' do
   # Depend on the generated AuthTestService library.
   pod 'AuthTestService', :path => '.'
 
   # Depend on Google's OAuth2 library
   pod 'Google/SignIn'
-
-  pod '!ProtoCompiler',  :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
-  pod '!ProtoCompiler-gRPCPlugin', :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
 end

examples/objective-c/helloworld/HelloWorld.podspec

@@ -13,20 +13,20 @@ Pod::Spec.new do |s|
   # Base directory where the .proto files are.
   src = "../../protos"
 
-  # Directory where the generated files will be placed.
-  dir = "Pods/" + s.name
-
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
   s.dependency "!ProtoCompiler-gRPCPlugin", "~> 0.14"
 
-  repo_root = '../../..'
-  pods_root = "#{repo_root}/examples/objective-c/helloworld/Pods"
+  # Pods directory corresponding to this app's Podfile, relative to the location of this podspec.
+  pods_root = './Pods'
 
+  # Path where Cocoapods downloads protoc and the gRPC plugin.
   protoc_dir = "#{pods_root}/!ProtoCompiler"
   protoc = "#{protoc_dir}/protoc"
-
   plugin = "#{pods_root}/!ProtoCompiler-gRPCPlugin/grpc_objective_c_plugin"
 
+  # Directory where the generated files will be placed.
+  dir = "#{pods_root}/#{s.name}"
+
   s.prepare_command = <<-CMD
     mkdir -p #{dir}
     #{protoc} \
@@ -38,21 +38,25 @@ Pod::Spec.new do |s|
         #{src}/helloworld.proto
   CMD
 
+  # Files generated by protoc
   s.subspec "Messages" do |ms|
     ms.source_files = "#{dir}/*.pbobjc.{h,m}", "#{dir}/**/*.pbobjc.{h,m}"
     ms.header_mappings_dir = dir
     ms.requires_arc = false
+    # The generated files depend on the protobuf runtime.
     ms.dependency "Protobuf"
     # This is needed by all pods that depend on Protobuf:
     ms.pod_target_xcconfig = {
       'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
     }
   end
 
+  # Files generated by the gRPC plugin
   s.subspec "Services" do |ss|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
+    # The generated files depend on the gRPC runtime, and on the files generated by protoc.
     ss.dependency "gRPC-ProtoRPC"
     ss.dependency "#{s.name}/Messages"
   end

examples/objective-c/helloworld/Podfile

@@ -3,13 +3,7 @@ platform :ios, '8.0'
 
 install! 'cocoapods', :deterministic_uuids => false
 
-# Location of gRPC's repo root relative to this file.
-GRPC_LOCAL_SRC = '../../..'
-
 target 'HelloWorld' do
   # Depend on the generated HelloWorld library.
   pod 'HelloWorld', :path => '.'
-
-  pod '!ProtoCompiler',  :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
-  pod '!ProtoCompiler-gRPCPlugin', :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
 end

examples/objective-c/route_guide/Podfile

@@ -3,13 +3,7 @@ platform :ios, '8.0'
 
 install! 'cocoapods', :deterministic_uuids => false
 
-# Location of gRPC's repo root relative to this file.
-GRPC_LOCAL_SRC = '../../..'
-
 target 'RouteGuideClient' do
   # Depend on the generated RouteGuide library.
   pod 'RouteGuide', :path => '.'
-
-  pod '!ProtoCompiler',  :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
-  pod '!ProtoCompiler-gRPCPlugin', :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c"
 end

examples/objective-c/route_guide/RouteGuide.podspec

@@ -13,20 +13,20 @@ Pod::Spec.new do |s|
   # Base directory where the .proto files are.
   src = "../../protos"
 
-  # Directory where the generated files will be placed.
-  dir = "Pods/" + s.name
-
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
   s.dependency "!ProtoCompiler-gRPCPlugin", "~> 0.14"
 
-  repo_root = '../../..'
-  pods_root = "#{repo_root}/examples/objective-c/route_guide/Pods"
+  # Pods directory corresponding to this app's Podfile, relative to the location of this podspec.
+  pods_root = './Pods'
 
+  # Path where Cocoapods downloads protoc and the gRPC plugin.
   protoc_dir = "#{pods_root}/!ProtoCompiler"
   protoc = "#{protoc_dir}/protoc"
-
   plugin = "#{pods_root}/!ProtoCompiler-gRPCPlugin/grpc_objective_c_plugin"
 
+  # Directory where the generated files will be placed.
+  dir = "#{pods_root}/#{s.name}"
+
   s.prepare_command = <<-CMD
     mkdir -p #{dir}
     #{protoc} \
@@ -38,21 +38,25 @@ Pod::Spec.new do |s|
         #{src}/route_guide.proto
   CMD
 
+  # Files generated by protoc
   s.subspec "Messages" do |ms|
     ms.source_files = "#{dir}/*.pbobjc.{h,m}", "#{dir}/**/*.pbobjc.{h,m}"
     ms.header_mappings_dir = dir
     ms.requires_arc = false
+    # The generated files depend on the protobuf runtime.
     ms.dependency "Protobuf"
     # This is needed by all pods that depend on Protobuf:
     ms.pod_target_xcconfig = {
       'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
     }
   end
 
+  # Files generated by the gRPC plugin
   s.subspec "Services" do |ss|
     ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
     ss.header_mappings_dir = dir
     ss.requires_arc = true
+    # The generated files depend on the gRPC runtime, and on the files generated by protoc.
     ss.dependency "gRPC-ProtoRPC"
     ss.dependency "#{s.name}/Messages"
   end

src/objective-c/README.md

@@ -1,12 +1,12 @@
 [![Cocoapods](https://img.shields.io/cocoapods/v/gRPC.svg)](https://cocoapods.org/pods/gRPC)
 # gRPC for Objective-C
 
-- [Install protoc with the gRPC plugin](#install)
 - [Write your API declaration in proto format](#write-protos)
 - [Integrate a proto library in your project](#cocoapods)
 - [Use the generated library in your code](#use)
 - [Use gRPC without Protobuf](#no-proto)
-- [Alternative installation methods](#alternatives)
+- [Alternatives to the steps above](#alternatives)
+    - [Install protoc with the gRPC plugin](#install)
     - [Install protoc and the gRPC plugin without using Homebrew](#no-homebrew)
     - [Integrate the generated gRPC library without using Cocoapods](#no-cocoapods)
 
@@ -15,18 +15,6 @@ usage and adds some interoperability guarantees. Here we use [Protocol Buffers][
 plugin for the Protobuf Compiler (_protoc_) to generate client libraries to communicate with gRPC
 services.
 
-<a name="install"></a>
-## Install protoc with the gRPC plugin
-
-On Mac OS X, install [homebrew][].
-
-Run the following command to install _protoc_ and the gRPC _protoc_ plugin:
-```sh
-$ curl -fsSL https://goo.gl/getgrpc | bash -
-```
-This will download and run the [gRPC install script][]. After the command completes, you're ready to
-proceed.
-
 <a name="write-protos"></a>
 ## Write your API declaration in proto format
 
@@ -40,7 +28,8 @@ Install [Cocoapods](https://cocoapods.org/#install).
 
 You need to create a Podspec file for your proto library. You may simply copy the following example
 to the directory where your `.proto` files are located, updating the name, version and license as
-necessary:
+necessary. You also need to set the `pods_root` variable to the correct value, depending on where
+you place this podspec relative to your Podfile.
 
 ```ruby
 Pod::Spec.new do |s|
@@ -55,16 +44,44 @@ Pod::Spec.new do |s|
   s.ios.deployment_target = '7.1'
   s.osx.deployment_target = '10.9'
 
+  # Base directory where the .proto files are.
+  src = '.'
+
+  # We'll use protoc with the gRPC plugin.
+  s.dependency '!ProtoCompiler-gRPCPlugin', '~> 0.14'
+
+  # Pods directory corresponding to this app's Podfile, relative to the location of this podspec.
+  pods_root = '<path to your Podfile>/Pods'
+
+  # Path where Cocoapods downloads protoc and the gRPC plugin.
+  protoc_dir = "#{pods_root}/!ProtoCompiler"
+  protoc = "#{protoc_dir}/protoc"
+  plugin = "#{pods_root}/!ProtoCompiler-gRPCPlugin/grpc_objective_c_plugin"
+
+  # Directory where you want the generated files to be placed. This is an example.
+  dir = "#{pods_root}/#{s.name}"
+
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
   # You can run this command manually if you later change your protos and need to regenerate.
-  s.prepare_command = "protoc --objc_out=. --objcgrpc_out=. *.proto"
+  # Alternatively, you can advance the version of this podspec and run `pod update`.
+  s.prepare_command = <<-CMD
+    mkdir -p #{dir}
+    #{protoc} \
+        --plugin=protoc-gen-grpc=#{plugin} \
+        --objc_out=#{dir} \
+        --grpc_out=#{dir} \
+        -I #{src} \
+        -I #{protoc_dir} \
+        #{src}/*.proto
+  CMD
 
   # The --objc_out plugin generates a pair of .pbobjc.h/.pbobjc.m files for each .proto file.
-  s.subspec "Messages" do |ms|
-    ms.source_files = "*.pbobjc.{h,m}"
-    ms.header_mappings_dir = "."
+  s.subspec 'Messages' do |ms|
+    ms.source_files = "#{dir}/*.pbobjc.{h,m}"
+    ms.header_mappings_dir = dir
     ms.requires_arc = false
-    ms.dependency "Protobuf", "~> 3.0.0-beta-2"
+    # The generated files depend on the protobuf runtime.
+    ms.dependency 'Protobuf'
     # This is needed by all pods that depend on Protobuf:
     ms.pod_target_xcconfig = {
       'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
@@ -73,11 +90,12 @@ Pod::Spec.new do |s|
 
   # The --objcgrpc_out plugin generates a pair of .pbrpc.h/.pbrpc.m files for each .proto file with
   # a service defined.
-  s.subspec "Services" do |ss|
-    ss.source_files = "*.pbrpc.{h,m}"
-    ss.header_mappings_dir = "."
+  s.subspec 'Services' do |ss|
+    ss.source_files = "#{dir}/*.pbrpc.{h,m}"
+    ss.header_mappings_dir = dir
     ss.requires_arc = true
-    ss.dependency "gRPC-ProtoRPC", "~> 0.14"
+    # The generated files depend on the gRPC runtime, and on the files generated by `--objc_out`.
+    ss.dependency 'gRPC-ProtoRPC'
     ss.dependency "#{s.name}/Messages"
   end
 end
@@ -89,11 +107,14 @@ Note: If your proto files are in a directory hierarchy, you might want to adjust
 the sample Podspec above. For example, you could use:
 
 ```ruby
-  s.prepare_command = "protoc --objc_out=. --objcgrpc_out=. *.proto **/*.proto"
+  s.prepare_command = <<-CMD
+    ...
+        #{src}/*.proto #{src}/**/*.proto
+  CMD
   ...
-    ms.source_files = "*.pbobjc.{h,m}", "**/*.pbobjc.{h,m}"
+    ms.source_files = "#{dir}/*.pbobjc.{h,m}", "#{dir}/**/*.pbobjc.{h,m}"
   ...
-    ss.source_files = "*.pbrpc.{h,m}", "**/*.pbrpc.{h,m}"
+    ss.source_files = "#{dir}/*.pbrpc.{h,m}", "#{dir}/**/*.pbrpc.{h,m}"
 ```
 
 Once your library has a Podspec, Cocoapods can install it into any XCode project. For that, go into
@@ -121,19 +142,33 @@ pod install
 <a name="use"></a>
 ## Use the generated library in your code
 
-Please check this [sample app][] for examples of how to use a generated gRPC library.
+Please check the [example apps][] for examples of how to use a generated gRPC library.
 
 <a name="no-proto"></a>
 ## Use gRPC without Protobuf
 
-The [sample app][] has an example of how to use the generic gRPC Objective-C client without
-generated files.
+This [tests file](https://github.com/grpc/grpc/tree/master/src/objective-c/tests/GRPCClientTests.m)
+shows how to use the generic gRPC Objective-C client without generated protobuf files.
 
 <a name="alternatives"></a>
-## Alternative installation methods
+## Alternatives to the steps above
+
+<a name="install"></a>
+### Install _protoc_ with the gRPC plugin
+
+Although it's not recommended (because it can lead to hard-to-solve version conflicts), it is
+sometimes more convenient to install _protoc_ and the gRPC plugin in your development machine,
+instead of letting Cocoapods download the appropriate versions for you. To do so, on Mac OS X or
+later, install [homebrew][].
+
+The run the following command to install _protoc_ and the gRPC _protoc_ plugin:
+```sh
+$ curl -fsSL https://goo.gl/getgrpc | bash -
+```
+This will download and run the [gRPC install script][].
 
 <a name="no-homebrew"></a>
-### Install protoc and the gRPC plugin without using Homebrew
+### Install _protoc_ and the gRPC plugin without using Homebrew
 
 First install v3 of the Protocol Buffers compiler (_protoc_), by cloning
 [its Git repository](https://github.com/google/protobuf) and following these
@@ -145,15 +180,15 @@ cloned.
 
 Compile the gRPC plugins for _protoc_:
 ```sh
-make plugins
+make grpc_objective_c_plugin
 ```
 
 Create a symbolic link to the compiled plugin binary somewhere in your `$PATH`:
 ```sh
 ln -s `pwd`/bins/opt/grpc_objective_c_plugin /usr/local/bin/protoc-gen-objcgrpc
 ```
-(Notice that the name of the created link must begin with "protoc-gen-" for _protoc_ to recognize it
-as a plugin).
+(Notice that the name of the created link must begin with "`protoc-gen-`" for _protoc_ to recognize
+it as a plugin).
 
 If you don't want to create the symbolic link, you can alternatively copy the binary (with the
 appropriate name). Or you might prefer instead to specify the plugin's path as a flag when invoking
@@ -178,5 +213,5 @@ Objective-C Protobuf runtime library.
 [Protocol Buffers]:https://developers.google.com/protocol-buffers/
 [homebrew]:http://brew.sh
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
-[example Podfile]:https://github.com/grpc/grpc/blob/master/src/objective-c/examples/Sample/Podfile
-[sample app]: https://github.com/grpc/grpc/tree/master/src/objective-c/examples/Sample
+[example Podfile]:https://github.com/grpc/grpc/blob/master/examples/objective-c/helloworld/Podfile
+[example apps]: https://github.com/grpc/grpc/tree/master/examples/objective-c