Update cocoapods and podspec script (#1122)

Motivation:

The podspec script uses Package.resolved to determine dependencies for
the 'GRPC' module as well as version requirements. These version
requirements are wrong per se, but they are overly restrictire.
Additionally, while Package.resolved was previously correct, it no
longer takes into account dependencies resolved for non-product targets
(i.e. swift-argument-parser).

Modifications:

- Build podspec dependency requirements from 'swift package dump-package'
- Replace 'os.system' with 'subprocess.check_call'
- Update pods

Result:

Pod dependency requirementments match Package.swift

CGRPCZlib.podspec

@@ -2,7 +2,7 @@ Pod::Spec.new do |s|
 
     s.name = 'CGRPCZlib'
     s.module_name = 'CGRPCZlib'
-    s.version = '1.0.0-alpha.23'
+    s.version = '1.0.0-alpha.24'
     s.license = { :type => 'Apache 2.0', :file => 'LICENSE' }
     s.summary = 'Compression library that provides in-memory compression and decompression functions'
     s.homepage = 'https://www.grpc.io'

gRPC-Swift-Plugins.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
 
     s.name = 'gRPC-Swift-Plugins'
-    s.version = '1.0.0-alpha.23'
+    s.version = '1.0.0-alpha.24'
     s.license = { :type => 'Apache 2.0', :file => 'LICENSE' }
     s.summary = 'Swift gRPC code generator plugin binaries'
     s.homepage = 'https://www.grpc.io'

gRPC-Swift.podspec

@@ -2,7 +2,7 @@ Pod::Spec.new do |s|
 
     s.name = 'gRPC-Swift'
     s.module_name = 'GRPC'
-    s.version = '1.0.0-alpha.23'
+    s.version = '1.0.0-alpha.24'
     s.license = { :type => 'Apache 2.0', :file => 'LICENSE' }
     s.summary = 'Swift gRPC code generator plugin and runtime library'
     s.homepage = 'https://www.grpc.io'
@@ -17,13 +17,13 @@ Pod::Spec.new do |s|
 
     s.source_files = 'Sources/GRPC/**/*.{swift,c,h}'
 
-    s.dependency 'Logging', '>= 1.4.0', '< 2'
-    s.dependency 'SwiftNIO', '>= 2.25.0', '< 3'
-    s.dependency 'SwiftNIOExtras', '>= 1.7.0', '< 2'
-    s.dependency 'SwiftNIOHTTP2', '>= 1.16.2', '< 2'
-    s.dependency 'SwiftNIOSSL', '>= 2.10.1', '< 3'
-    s.dependency 'SwiftNIOTransportServices', '>= 1.9.1', '< 2'
-    s.dependency 'SwiftProtobuf', '>= 1.14.0', '< 2'
+    s.dependency 'SwiftProtobuf', '>= 1.9.0', '< 2.0.0'
+    s.dependency 'SwiftNIO', '>= 2.22.0', '< 3.0.0'
+    s.dependency 'SwiftNIOTransportServices', '>= 1.6.0', '< 2.0.0'
+    s.dependency 'SwiftNIOSSL', '>= 2.8.0', '< 3.0.0'
+    s.dependency 'SwiftNIOExtras', '>= 1.4.0', '< 2.0.0'
+    s.dependency 'Logging', '>= 1.4.0', '< 2.0.0'
+    s.dependency 'SwiftNIOHTTP2', '>= 1.16.1', '< 2.0.0'
     s.dependency 'CGRPCZlib', s.version.to_s
 
 end

scripts/build_podspecs.py

@@ -19,20 +19,28 @@ import json
 import random
 import string
 import argparse
+import subprocess
+import sys
 
-class Dependency:
-    def __init__(self, name, version='s.version.to_s', use_verbatim_version=True):
+
+class TargetDependency(object):
+    def __init__(self, name):
         self.name = name
-        self.version = version
-        self.use_verbatim_version = use_verbatim_version
 
-    def as_podspec(self):
-        indent='    '
+    def __str__(self):
+        return "s.dependency '{name}', s.version.to_s".format(name=self.name)
 
-        if self.use_verbatim_version:
-            return indent + "s.dependency '%s', %s\n" % (self.name, self.version)
 
-        return indent + "s.dependency '%s', '%s'\n" % (self.name, self.version)
+class ProductDependency(object):
+    def __init__(self, name, lower, upper):
+        self.name = name
+        self.lower = lower
+        self.upper = upper
+
+    def __str__(self):
+        return "s.dependency '{name}', '>= {lower}', '< {upper}'".format(
+                name=self.name, lower=self.lower, upper=self.upper)
+
 
 class Pod:
     def __init__(self, name, module_name, version, description, dependencies=None, is_plugins_pod=False):
@@ -40,16 +48,9 @@ class Pod:
         self.module_name = module_name
         self.version = version
         self.is_plugins_pod = is_plugins_pod
-
-        if dependencies is None:
-            dependencies = []
-
-        self.dependencies = dependencies
+        self.dependencies = dependencies if dependencies is not None else []
         self.description = description
 
-    def add_dependency(self, dependency):
-        self.dependencies.append(dependency)
-
     def as_podspec(self):
         print('\n')
         print('Building Podspec for %s' % self.name)
@@ -83,16 +84,17 @@ class Pod:
             podspec += "\n" if len(self.dependencies) > 0 else ""
 
         for dep in self.dependencies:
-            podspec += dep.as_podspec()
+            podspec += indent + str(dep) + "\n"
 
         podspec += "\nend"
         return podspec
 
 class PodManager:
-    def __init__(self, directory, version, should_publish):
+    def __init__(self, directory, version, should_publish, package_dump):
         self.directory = directory
         self.version = version
         self.should_publish = should_publish
+        self.package_dump = package_dump
 
     def write(self, pod, contents):
         print('    Writing to %s/%s.podspec ' % (self.directory, pod))
@@ -100,24 +102,26 @@ class PodManager:
             podspec_file.write(contents)
 
     def publish(self, pod_name):
-        os.system('pod repo update')
+        subprocess.check_call(['pod', 'repo', 'update'])
         print('    Publishing %s.podspec' % (pod_name))
-        os.system('pod trunk push --synchronous %s/%s.podspec' % (self.directory, pod_name))
+        subprocess.check_call(['pod', 'trunk', 'push', '--synchronous',
+                               self.directory + '/' + pod_name])
 
     def build_pods(self):
         cgrpczlib_pod = Pod(
-            'CGRPCZlib',
+            self.pod_name_for_grpc_target('CGRPCZlib'),
             'CGRPCZlib',
             self.version,
-            'Compression library that provides in-memory compression and decompression functions'
+            'Compression library that provides in-memory compression and decompression functions',
+            dependencies=self.build_dependency_list('CGRPCZlib')
         )
 
         grpc_pod = Pod(
-            'gRPC-Swift',
+            self.pod_name_for_grpc_target('GRPC'),
             'GRPC',
             self.version,
             'Swift gRPC code generator plugin and runtime library',
-            get_grpc_deps()
+            dependencies=self.build_dependency_list('GRPC')
         )
 
         grpc_plugins_pod = Pod(
@@ -125,13 +129,10 @@ class PodManager:
             '',
             self.version,
             'Swift gRPC code generator plugin binaries',
-            [],
+            dependencies=[TargetDependency("gRPC-Swift")],
             is_plugins_pod=True
         )
 
-        grpc_pod.add_dependency(Dependency(cgrpczlib_pod.name))
-        grpc_plugins_pod.add_dependency(Dependency(grpc_pod.name))
-
         return [cgrpczlib_pod, grpc_pod, grpc_plugins_pod]
 
     def go(self, start_from):
@@ -148,33 +149,91 @@ class PodManager:
             else:
                 print('    Skipping Publishing...')
 
-def process_package(string):
-    pod_mappings = {
-        'swift-log': 'Logging',
-        'swift-nio': 'SwiftNIO',
-        'swift-nio-extras': 'SwiftNIOExtras',
-        'swift-nio-http2': 'SwiftNIOHTTP2',
-        'swift-nio-ssl': 'SwiftNIOSSL',
-        'swift-nio-transport-services': 'SwiftNIOTransportServices',
-        'SwiftProtobuf': 'SwiftProtobuf'
-    }
 
-    return pod_mappings[string]
+    def pod_name_for_package(self, name):
+        """Return the CocoaPod name for a given Swift package."""
+        pod_mappings = {
+            'swift-log': 'Logging',
+            'swift-nio': 'SwiftNIO',
+            'swift-nio-extras': 'SwiftNIOExtras',
+            'swift-nio-http2': 'SwiftNIOHTTP2',
+            'swift-nio-ssl': 'SwiftNIOSSL',
+            'swift-nio-transport-services': 'SwiftNIOTransportServices',
+            'SwiftProtobuf': 'SwiftProtobuf'
+        }
+        return pod_mappings[name]
+
+
+    def pod_name_for_grpc_target(self, name):
+        """Return the CocoaPod name for a given gRPC Swift target."""
+        return {
+          'GRPC': 'gRPC-Swift',
+          'CGRPCZlib': 'CGRPCZlib'
+        }[name]
 
-def get_grpc_deps():
-    with open('Package.resolved') as package:
-        data = json.load(package)
 
-    deps = []
+    def get_package_requirements(self, package_name):
+        """
+        Returns the lower and upper bound version requirements for a given
+        package dependency.
+        """
+        for dependency in self.package_dump['dependencies']:
+            if dependency['name'] == package_name:
+                # There should only be 1 range.
+                requirement = dependency['requirement']['range'][0]
+                return (requirement['lowerBound'], requirement['upperBound'])
 
-    for obj in data['object']['pins']:
-        package = process_package(obj['package'])
-        version = obj['state']['version']
-        next_major_version = int(version.split('.')[0]) + 1
+        # This shouldn't happen.
+        raise ValueError('Could not find package called', package_name)
 
-        deps.append(Dependency(package, '\'>= {}\', \'< {}\''.format(version, next_major_version)))
 
-    return deps
+    def get_dependencies(self, target_name):
+        """
+        Returns a tuple of dependency lists for a given target.
+
+        The first entry is the list of product dependencies; dependencies on
+        products from other packages. The second entry is a list of target
+        dependencies, i.e. dependencies on other targets within the package.
+        """
+        for target in self.package_dump['targets']:
+            if target['name'] == target_name:
+                product_dependencies = set()
+                target_dependencies = []
+
+                for dependency in target['dependencies']:
+                    if 'product' in dependency:
+                        product_dependencies.add(dependency['product'][1])
+                    elif 'target' in dependency:
+                        target_dependencies.append(dependency['target'][0])
+                    else:
+                        raise ValueError('Unexpected dependency type:', dependency)
+
+                return (product_dependencies, target_dependencies)
+
+        # This shouldn't happen.
+        raise ValueError('Could not find dependency called', target_name)
+
+
+    def build_dependency_list(self, target_name):
+        """
+        Returns a list of dependencies for the given target.
+
+        Dependencies may be either 'TargetDependency' or 'ProductDependency'.
+        """
+        product, target = self.get_dependencies(target_name)
+        dependencies = []
+
+        for package_name in product:
+            (lower, upper) = self.get_package_requirements(package_name)
+            pod_name = self.pod_name_for_package(package_name)
+            dependencies.append(ProductDependency(pod_name, lower, upper))
+
+        for target_name in target:
+            pod_name = self.pod_name_for_grpc_target(target_name)
+            dependencies.append(TargetDependency(pod_name))
+
+        return dependencies
+
 
 def dir_path(path):
     if os.path.isdir(path):
@@ -206,7 +265,6 @@ def main():
     )
 
     parser.add_argument('version')
-
     args = parser.parse_args()
 
     should_publish = args.upload
@@ -217,7 +275,12 @@ def main():
     if not path:
         path = os.getcwd()
 
-    pod_manager = PodManager(path, version, should_publish)
+    print("Reading package description...")
+    lines = subprocess.check_output(["swift", "package", "dump-package"])
+    package_dump = json.loads(lines)
+    assert(package_dump["name"] == "grpc-swift")
+
+    pod_manager = PodManager(path, version, should_publish, package_dump)
     pod_manager.go(start_from)
 
     return 0