Tavern GRPC support (#438)

---------

Co-authored-by: Kirils Mensikovs <kirils.mensikovs@cognite.com>
Co-authored-by: michaelboulton <michaelboulton@users.noreply.github.com>
Co-authored-by: Michael Boulton <michaelboulton@gmail.com>

.gitattributes

@@ -0,0 +1,3 @@
+**/*_pb2.py linguist-generated
+**/*_pb2_grpc.py linguist-generated
+**/*_pb2.pyi linguist-generated

.github/workflows/main.yml

@@ -89,6 +89,8 @@ jobs:
             TOXCFG: tox-integration.ini
           - TOXENV: py3-advanced
             TOXCFG: tox-integration.ini
+          - TOXENV: py3-grpc
+            TOXCFG: tox-integration.ini
 
     services:
       docker:
@@ -123,6 +125,12 @@ jobs:
         with:
           python-version: "3.11"
 
+      - name: Install Protoc
+        if: ${{ contains(matrix.TOXENV, 'grpc') }}
+        uses: arduino/setup-protoc@v2
+        with:
+          version: "23.x"
+
       - name: install deps
         run: |
           pip install tox -c constraints.txt

.gitignore

@@ -125,3 +125,4 @@ bazel-out
 bazel-tavern
 bazel-testlogs
 
+example/grpc/proto

CONTRIBUTING.md

@@ -23,8 +23,10 @@ If on Windows, you should be able to just run the 'tox' commands in that file.
 
 1. Update requirements files (BOTH of them)
 
-       pip-compile --all-extras --resolver=backtracking pyproject.toml --output-file requirements.txt --reuse-hashes --generate-hashes
-       pip-compile --all-extras --resolver=backtracking pyproject.toml --output-file constraints.txt --strip-extras
+```shell
+pip-compile --all-extras --resolver=backtracking pyproject.toml --output-file requirements.txt --reuse-hashes --generate-hashes -U
+pip-compile --all-extras --resolver=backtracking pyproject.toml --output-file constraints.txt --strip-extras -U
+```
 
 1. Run tests as above
 

MANIFEST.in

@@ -1,3 +1,4 @@
 include tavern/_core/schema/tests.jsonschema.yaml
 include tavern/_plugins/mqtt/jsonschema.yaml
+include tavern/_plugins/grpc/schema.yaml
 include LICENSE

constraints.txt

@@ -2,7 +2,7 @@
 # This file is autogenerated by pip-compile with Python 3.11
 # by the following command:
 #
-#    pip-compile --all-extras --output-file=constraints.txt --resolver=backtracking --strip-extras pyproject.toml
+#    pip-compile --all-extras --output-file=constraints.txt --strip-extras pyproject.toml
 #
 alabaster==0.7.16
     # via sphinx
@@ -25,7 +25,9 @@ build==1.0.3
 bump2version==1.0.1
     # via tavern (pyproject.toml)
 cachetools==5.3.2
-    # via tox
+    # via
+    #   google-auth
+    #   tox
 certifi==2023.11.17
     # via requests
 cffi==1.16.0
@@ -68,20 +70,54 @@ docutils==0.20.1
     #   tavern (pyproject.toml)
 execnet==2.0.2
     # via pytest-xdist
-faker==22.2.0
+faker==22.4.0
     # via tavern (pyproject.toml)
 filelock==3.13.1
     # via
     #   tox
     #   virtualenv
-flask==3.0.0
+flask==3.0.1
     # via tavern (pyproject.toml)
 flit==3.9.0
     # via tavern (pyproject.toml)
 flit-core==3.9.0
     # via flit
 fluent-logger==0.10.0
     # via tavern (pyproject.toml)
+google-api-core==2.15.0
+    # via google-api-python-client
+google-api-python-client==2.114.0
+    # via tavern (pyproject.toml)
+google-auth==2.26.2
+    # via
+    #   google-api-core
+    #   google-api-python-client
+    #   google-auth-httplib2
+google-auth-httplib2==0.2.0
+    # via google-api-python-client
+googleapis-common-protos==1.62.0
+    # via
+    #   google-api-core
+    #   grpcio-status
+grpc-interceptor==0.15.4
+    # via tavern (pyproject.toml)
+grpcio==1.60.0
+    # via
+    #   grpc-interceptor
+    #   grpcio-reflection
+    #   grpcio-status
+    #   grpcio-tools
+    #   tavern (pyproject.toml)
+grpcio-reflection==1.60.0
+    # via tavern (pyproject.toml)
+grpcio-status==1.60.0
+    # via tavern (pyproject.toml)
+grpcio-tools==1.60.0
+    # via tavern (pyproject.toml)
+httplib2==0.22.0
+    # via
+    #   google-api-python-client
+    #   google-auth-httplib2
 identify==2.5.33
     # via pre-commit
 idna==3.6
@@ -110,7 +146,7 @@ jinja2==3.1.3
     #   sphinx
 jmespath==1.0.1
     # via tavern (pyproject.toml)
-jsonschema==4.21.0
+jsonschema==4.21.1
     # via tavern (pyproject.toml)
 jsonschema-specifications==2023.12.1
     # via jsonschema
@@ -120,7 +156,7 @@ markdown==3.5.2
     # via sphinx-markdown-tables
 markdown-it-py==3.0.0
     # via rich
-markupsafe==2.1.3
+markupsafe==2.1.4
     # via
     #   jinja2
     #   werkzeug
@@ -166,8 +202,25 @@ pluggy==1.3.0
     #   tox
 pre-commit==3.6.0
     # via tavern (pyproject.toml)
+proto-plus==1.23.0
+    # via tavern (pyproject.toml)
+protobuf==4.25.2
+    # via
+    #   google-api-core
+    #   googleapis-common-protos
+    #   grpcio-reflection
+    #   grpcio-status
+    #   grpcio-tools
+    #   proto-plus
+    #   tavern (pyproject.toml)
 py==1.11.0
     # via tavern (pyproject.toml)
+pyasn1==0.5.1
+    # via
+    #   pyasn1-modules
+    #   rsa
+pyasn1-modules==0.3.0
+    # via google-auth
 pycparser==2.21
     # via cffi
 pygments==2.17.2
@@ -180,6 +233,8 @@ pyjwt==2.8.0
     # via tavern (pyproject.toml)
 pykwalify==1.8.0
     # via tavern (pyproject.toml)
+pyparsing==3.1.1
+    # via httplib2
 pyproject-api==1.6.1
     # via tox
 pyproject-hooks==1.0.0
@@ -215,6 +270,7 @@ referencing==0.32.1
 requests==2.31.0
     # via
     #   flit
+    #   google-api-core
     #   requests-toolbelt
     #   sphinx
     #   tavern (pyproject.toml)
@@ -229,11 +285,13 @@ rpds-py==0.17.1
     # via
     #   jsonschema
     #   referencing
+rsa==4.9
+    # via google-auth
 ruamel-yaml==0.18.5
     # via pykwalify
 ruamel-yaml-clib==0.2.8
     # via ruamel-yaml
-ruff==0.1.13
+ruff==0.1.14
     # via tavern (pyproject.toml)
 secretstorage==3.3.3
     # via keyring
@@ -281,6 +339,8 @@ types-setuptools==69.0.0.20240115
     # via tavern (pyproject.toml)
 typing-extensions==4.9.0
     # via mypy
+uritemplate==4.1.1
+    # via google-api-python-client
 urllib3==2.1.0
     # via
     #   requests

docs/source/conf.py

@@ -29,7 +29,6 @@
 # needs_sphinx = '1.0'
 
 import sphinx_rtd_theme
-import recommonmark
 from recommonmark.transform import AutoStructify
 
 # Add any Sphinx extension module names here, as strings. They can be

docs/source/grpc.md

@@ -0,0 +1,168 @@
+# gRPC integration testing
+
+## Current limitations / future plans
+
+- Should be able to specify channel credentials.
+- Currently there is no way of doing custom TLS options (like with rest/mqtt)
+- Better syntax around importing modules
+- Some way of representing streaming RPCs? This is pretty niche and Tavern is built around a core of only making 1
+  request which doesn't work well with streaming request RPCs, but streaming response RPCs could be handled like
+  multiple MQTT responses.
+- Much like the tavern-flask plugin it wouldn't be too difficult to write a plugin which started a Python gRPC server
+  in-process and ran tests against that instead of having to use a remote server
+- Fix comparing results - currently it serialises with
+
+      including_default_value_fields=True,
+      preserving_proto_field_name=True,
+
+  Which formats a field like `my_field_name` as `my_field_name` and not `myFieldName` which is what protojson in Go
+  converts it to for example, need to provide a way to allow people to write tests using either one
+- protos are compiled into a folder based on `tempfile.gettempdir()`, this could be configurable
+
+## Connection
+
+There are 2 ways of specifying the grpc connection, in the `grpc` block at the top of the test similarly to an mqtt
+connection block, or in the test stage itself.
+
+In the `grpc.connect` block:
+
+```yaml
+grpc:
+  connect:
+    host: localhost
+    port: 50052
+```
+
+In the test stage itself:
+
+```yaml
+stages:
+  - name: Do a thing
+    grpc_request:
+      host: "localhost: 50052"
+      service: my.cool.service/Waoh
+      body:
+        ...
+```
+
+The connection will be established at the beginning of the test and dropped when it finishes.
+
+### SSL connection
+
+Tavern currently _defaults to an insecure connection_ when connecting to grpc, to enable SSL connections add
+the `secure` key in the `connect` block:
+
+```yaml
+grpc:
+  connect:
+    secure: true
+```
+
+### Metadata
+
+Generic metadata can be passed on every message using the `metadata` key:
+
+```yaml
+grpc:
+  metadata:
+    my-extra-info: something
+```
+
+### Advanced: connection options
+
+Generic connection options can be passed as key:value pairs under the `options` block:
+
+```yaml
+grpc:
+  connect:
+    options:
+      grpc.max_send_message_length: 10000000
+```
+
+See [the gRPC documentation](https://grpc.github.io/grpc/core/group__grpc__arg__keys.html) for a list of possible
+options, note that some of these may not be implemented in Python.
+
+## Requests
+
+The `grpc_request` block requires, at minimum, the name of the service to send the request to
+
+```yaml
+stages:
+  - name: Say hello
+    grpc_request:
+      service: helloworld.v3.Greeter/SayHello
+      body:
+        name: "John"
+```
+
+The 'body' block will be reflected into the protobuf message type expected for the service, if the schema is invalid
+then an exception will be raised.
+
+## Responses
+
+If no response is specified, Tavern will assume that _any_ response with an `OK` status code to be successful.
+
+Other status codes are specified using the `status` key. The gRPC status code should be a string matching
+a [gRPC status code](https://grpc.github.io/grpc/core/md_doc_statuscodes.html), for
+example `OK`, `NOT_FOUND`, etc. or the numerical value of the code. It can also be a list of codes.
+
+```yaml
+stages:
+  - name: Echo text
+    grpc_request:
+      service: helloworld.v1.Greeter/SayHello
+      body:
+        name: "John"
+    grpc_response:
+      status: "OK"  # Also the default
+```
+
+## Loading protobuf definitions
+
+There are 3 different ways Tavern will try to load the appropriate proto definitions:
+
+#### Specifying the proto module to use
+
+If you already have all the Python gRPC stubs in your repository. Example:
+
+```yaml
+grpc:
+  proto:
+    module: server/helloworld_pb2_grpc
+```
+
+This will attempt to import the given module (it should not be a Python file, but the path to the module containing the
+existing stubs) and register all the protos in it.
+
+#### Specifying a folder with some protos in
+
+Example:
+
+```yaml
+grpc:
+  proto:
+    source: path/to/protos
+```
+
+This will attempt to find all files ending in `.proto` in the given folder and compile them using
+the protoc compiler. It first checks the value of the environment variable `PROTOC` and use that,
+and if not defined it will then look for a binary called `protoc` in the path. proto files are
+compiled into a folder called `proto` under the same folder that the Tavern yaml is in.
+
+This has a few drawbacks, especially that if it can't find the protoc compiler at runtime it will
+fail, but it might be useful if you're talking to a Java/Go/other server and you don't want to keep
+some compiled Python gRPC stubs in your repository.
+
+#### Server reflection
+
+This is obviously the least useful method. If you don't specify a proto source or module, the client
+can attempt to
+use [gRPC reflection](https://github.com/grpc/grpc/blob/master/doc/server-reflection.md) to
+determine what is the appropriate message type for the message you're trying to send. This is not
+reliable as the server you're trying to talk to might not have reflection turned on. This needs to be specified in
+the `grpc` block:
+
+```yaml
+grpc:
+  attempt_reflection: true
+```

docs/source/index.md

@@ -32,6 +32,7 @@ Tavern is still in active development and is used by 100s of companies.
 * [Basic Concepts](basics.md)
 * [HTTP Integration testing](http.md)
 * [MQTT Integration testing](mqtt.md)
+* [gRPC Integration testing](grpc.md)
 * [Plugins](plugins.md)
 * [Debugging Tests](debugging.md)
 * [Examples](examples.md)