gRPC is designed to plug-in a number of authentication mechanisms. We provide an overview
of the various auth mechanisms supported, discuss the API and demonstrate usage through
code examples, and conclude with a discussion of extensibility.
gRPC is designed to plug-in a number of authentication mechanisms. This document provides a quick overview
of the various auth mechanisms supported, discusses the API with some examples, and concludes with a discussion of extensibility. More documentation and examples are coming soon!
## Supported auth mechanisms
###SSL/TLS
gRPC has SSL/TLS integration and promotes the use of SSL/TLS to authenticate the server,
and encrypt all the data exchanged between the client and the server. Optional
mechanisms are available for clients to provide certificates to accomplish mutual
and encrypt all the data exchanged between the client and the server. Optional
mechanisms are available for clients to provide certificates to accomplish mutual
authentication.
###OAuth 2.0
gRPC provides a generic mechanism (described below) to attach metadata to requests
and responses. This mechanism can be used to attach OAuth 2.0 Access Tokens to
RPCs being made at a client. Additional support for acquiring Access Tokens while
accessing Google APIs through gRPC is provided for certain auth flows, demonstrated
gRPC provides a generic mechanism (described below) to attach metadata to requests
and responses. This mechanism can be used to attach OAuth 2.0 Access Tokens to
RPCs being made at a client. Additional support for acquiring Access Tokens while
accessing Google APIs through gRPC is provided for certain auth flows, demonstrated
through code examples below.
###API
To reduce complexity and minimize API clutter, gRPC works with a unified concept of
a Credentials object. Users construct gRPC credentials using corresponding bootstrap
credentials (e.g., SSL client certs or Service Account Keys), and use the
credentials while creating a gRPC channel to any server. Depending on the type of
credential supplied, the channel uses the credentials during the initial SSL/TLS
##Authentication API
To reduce complexity and minimize API clutter, gRPC works with a unified concept of
a Credentials object. Users construct gRPC credentials using corresponding bootstrap
credentials (e.g., SSL client certs or Service Account Keys), and use the
credentials while creating a gRPC channel to any server. Depending on the type of
credential supplied, the channel uses the credentials during the initial SSL/TLS
handshake with the server, or uses the credential to generate and attach Access
Tokens to each request being made on the channel.
###Code Examples
####SSL/TLS for server authentication and encryption
###SSL/TLS for server authentication and encryption
This is the simplest authentication scenario, where a client just wants to
authenticate the server and encrypt all data.
```
SslCredentialsOptions ssl_opts; // Options to override SSL params, empty by default
```cpp
SslCredentialsOptions ssl_opts; // Options to override SSL params, empty by default
// Create the credentials object by providing service account key in constructor
grpc::Status s = stub->sayHello(&context, *request, response);
```
This credential works for applications using Service Accounts as well as for
applications running in Google Compute Engine (GCE). In the former case, the
This credential works for applications using Service Accounts as well as for
applications running in [Google Compute Engine (GCE)](https://cloud.google.com/compute/). In the former case, the
service account’s private keys are loaded from the file named in the environment
variable `GOOGLE_APPLICATION_CREDENTIALS`. The
keys are used to generate bearer tokens that are attached to each outgoing RPC
keys are used to generate bearer tokens that are attached to each outgoing RPC
on the corresponding channel.
For applications running in GCE, a default service account and corresponding
@ -75,38 +75,40 @@ tokens and attaches them to each outgoing RPC on the corresponding channel.
Extending gRPC to support other authentication mechanisms
The gRPC protocol is designed with a general mechanism for sending metadata
associated with RPC. Clients can send metadata at the beginning of an RPC and
servers can send back metadata at the beginning and end of the RPC. This
provides a natural mechanism to support OAuth2 and other authentication
mechanisms that need attach bearer tokens to individual request.
servers can send back metadata at the beginning and end of the RPC. This
provides a natural mechanism to support OAuth2 and other authentication
mechanisms that need attach bearer tokens to individual request.
In the simplest case, there is a single line of code required on the client
to add a specific token as metadata to an RPC and a corresponding access on
the server to retrieve this piece of metadata. The generation of the token
to add a specific token as metadata to an RPC and a corresponding access on
the server to retrieve this piece of metadata. The generation of the token
on the client side and its verification at the server can be done separately.
A deeper integration can be achieved by plugging in a gRPC credentials implementation for any custom authentication mechanism that needs to attach per-request tokens. gRPC internals also allow switching out SSL/TLS with other encryption mechanisms.
These authentication mechanisms will be available in all gRPC's supported languages.
The following sections demonstrate how authentication and authorization features described above appear in each language
## Examples
####SSL/TLS for server authentication and encryption (Ruby)
gRPC's supported authentication mechanisms will be available in _all gRPC's supported languages_.
The following sections show how authentication and authorization features described above appear in each language (more examples coming soon).
###SSL/TLS for server authentication and encryption (Ruby)