This directory contains small examples showing how to use the Cloud Pub/Sub C++ client library in your own project. These instructions assume that you have some experience as a C++ developer and that you have a working C++ toolchain (compiler, linker, etc.) installed on your platform.
To run the quickstart program you will need a working Google Cloud Platform (GCP) project, and an existing Cloud Pub/Sub Topic. The Cloud Pub/Sub quickstarts is a good place to find information on how to setup a GCP project and create a topic. Make a note of the project and topic ids as you will need them later.
Like most Google Cloud Platform (GCP) services, Cloud Pub/Sub requires that
your application authenticates with the service before accessing any data. If
you are not familiar with GCP authentication please take this opportunity to
review the Authentication Overview. This library
uses the GOOGLE_APPLICATION_CREDENTIALS
environment variable to find the
credentials file. For example:
Shell | Command |
---|---|
Bash/zsh/ksh/etc. | export GOOGLE_APPLICATION_CREDENTIALS=[PATH] |
sh | GOOGLE_APPLICATION_CREDENTIALS=[PATH]; export GOOGLE_APPLICATION_CREDENTIALS |
csh/tsch | setenv GOOGLE_APPLICATION_CREDENTIALS [PATH] |
Windows Powershell | $env:GOOGLE_APPLICATION_CREDENTIALS=[PATH] |
Windows cmd.exe | set GOOGLE_APPLICATION_CREDENTIALS=[PATH] |
Setting this environment variable is the recommended way to configure the authentication preferences, though if the environment variable is not set, the library searches for a credentials file in the same location as the Cloud SDK. For more information about Application Default Credentials, see https://cloud.google.com/docs/authentication/production
⚠️ If you are using Windows or macOS there are additional instructions at the end of this document.
-
Install Bazel using the instructions from the
bazel.build
website. -
Compile this example using Bazel:
cd $HOME/google-cloud-cpp/google/cloud/pubsub/quickstart bazel build ...
Note that, as it is often the case with C++ libraries, compiling these dependencies may take several minutes.
-
Run the example, change the place holder to appropriate values:
bazel run :quickstart -- [GCP PROJECT ID] [TOPIC ID]
⚠️ If you are using Windows or macOS there are additional instructions at the end of this document.
-
Install CMake. The package managers for most Linux distributions include a package for CMake. Likewise, you can install CMake on Windows using a package manager such as chocolatey, and on macOS using homebrew. You can also obtain the software directly from the cmake.org.
-
Install the dependencies with your favorite tools. As an example, if you use vcpkg:
cd $HOME/vcpkg ./vcpkg install google-cloud-cpp
Note that, as it is often the case with C++ libraries, compiling these dependencies may take several minutes.
-
Configure CMake, if necessary, configure the directory where you installed the dependencies:
cd $HOME/gooogle-cloud-cpp/google/cloud/pubsub/quickstart cmake -H. -B.build -DCMAKE_TOOLCHAIN_FILE=$HOME/vcpkg/scripts/buildsystems/vcpkg.cmake cmake --build .build
-
Run the example, change the place holder to appropriate values:
.build/quickstart [GCP PROJECT ID] [PUB/SUB TOPIC ID]
gRPC requires an environment variable to configure the trust store for SSL certificates, you can download and configure this using:
curl -Lo roots.pem https://raw.githubusercontent.com/grpc/grpc/master/etc/roots.pem
export GRPC_DEFAULT_SSL_ROOTS_FILE_PATH="$PWD/roots.pem"
To workaround a bug in Bazel, gRPC requires this flag on
macOS builds, you can add the option manually or include it in your .bazelrc
file:
bazel build --copt=-DGRPC_BAZEL_BUILD ...
To correctly configure the MSVC runtime you should change the CMake minimum
required version to 3.15 or add -DCMAKE_POLICY_DEFAULT_CMP0091=NEW
to the
CMake configuration step.
gRPC requires an environment variable to configure the trust store for SSL certificates, you can download and configure this using:
@powershell -NoProfile -ExecutionPolicy unrestricted -Command ^
(new-object System.Net.WebClient).Downloadfile( ^
'https://raw.githubusercontent.com/grpc/grpc/master/etc/roots.pem', ^
'roots.pem')
set GRPC_DEFAULT_SSL_ROOTS_FILE_PATH=%cd%\roots.pem