Add Gitlab Connector (#1869)

* Initial work on the Gitlab connector

* Add initial events

* Add merge events

* Handle label event and use dataclass for payload

* Create issue events

* Add generic gitlab event, add connector, target and raw_event arguments to events

* initial work on tests

* Write first test

* More tests and handle weird payload cases

* Add more tests and handle more events

* Remove url from events, update docstrings

* Add docs, rename issue events due to conflicts

* Add gitlab docs and fix spacing for event lists

* Maybe I should have updated the tests, right?

* Refactor connector, allow to send message, update docs

* Update tests

* Add mock skill - no clue why it got deleted

* Update example

docs/_static/custom.css

@@ -5,3 +5,7 @@
     font-size: 12px;
     line-height: 1.8;
 }
+
+dl {
+    margin-bottom: 15px !important;
+}

docs/connectors/gitlab.md

@@ -0,0 +1,201 @@
+# GitLab
+
+A connector for [GitLab](https://gitlab.com). 
+
+Note that this connector emits only upports sending messages back
+to the event (Issue, Merge Request), if you need to create more elaborate workflow, please
+use the [GitLab API](https://docs.gitlab.com/ee/api/) in your skill.
+
+## Requirements
+
+- A GitLab Account
+- A repository setup with a [webhook](https://docs.gitlab.com/ee/user/project/integrations/webhooks.html)
+- A [personal Access token](https://gitlab.com/-/profile/personal_access_tokens) if you want to send messages to GitLab
+
+## Configuration
+
+```yaml
+connectors:
+  gitlab:
+    # Optional but recommended
+    webhook-token: "my-very-secret-webhook-secret"
+    # Required if you want opsdroid to reply to issues/MRs
+    token: "<personal access token>"
+```
+
+## Setup Webhook
+
+You need to [expose Opsdroid to the internet](../exposing.md), when you have your url, you can go to your repository, click **Settings** and then select **Webhook**, you can then add the url with the `connector/<connector name>` enpoint. For example, assume that you are using `example.com` as your base url and using this connector with the default name, you can use the following url `https://example.com/connector/gitlab` to receive events from your repository.
+
+You can then choose a secret token - this will be your `webhook-token` in the Opsdroid configuration. It's highly recommended that you choose
+a strong token to validate the requests coming into the `https://example.com/connector/gitlab` endpoint.
+
+Finally, you can choose which events you want Gitlab to send you and choose if you want to turn off SSL verification. It's recommended that
+you use SSL at all times.
+
+## Examples
+
+The GitLab connector allows you to send back a message when an event is triggered. This is a great way to automate some workflows. For example, let's assume that you want to thank every user that opens a new issue in your repository.
+
+Here's a small example of how the opsdroid configuration looks like:
+
+```yaml
+connectors:
+  gitlab:
+  webhook-token: "my-secret-token"
+  token: "my-personal-token"
+skills:
+  thankyou:
+    path: "<skill pwd>"
+```
+
+Then you can create a new folder for your skill and write the following:
+
+```python
+from opsdroid.skill import Skill
+from opsdorid.matchers import match_event
+from opsdroid.connector.gitlab.events import GitlabIssueCreated
+from opsdroid.events import Message
+
+class ThankUser(Skill):
+    def __init__(self, opsdroid, config, *args, **kwargs):
+        super().__init__(opsdroid, config, *args, **kwargs)
+        self.opsdroid = opsdroid
+
+    @match_event(GitlabIssueCreated)
+    async def say_thank_you(self, event):
+        """Send message to issue, thanking user."""
+        await event.respond(
+            Message(
+                text="Thank you for opening this issue, a team member will be with you shortly!",
+                target=event.target
+            )
+        )
+```
+
+Now let's assume that you want to notify a slack channel every time a label was changed in an MR. This can be useful if you want to alert your team that an MR is ready for code review.
+
+A more robust opsdroid configuration:
+
+```yaml
+connectors:
+  gitlab:
+    webhook-token: "/secret-t0k3n|"
+    token: "<your secret token>"
+  slack:
+    bot-token: "<your token>"
+    socket-mode: false
+    bot-name: "Review-Bot"
+    default-room: "#code-reviews"
+skills:
+  alert-team:
+    path: "<skill pwd>"
+```
+
+The skill will look somewhat similar to the previous example with a few changes:
+
+```python
+from opsdroid.skill import Skill
+from opsdorid.matchers import match_event
+from opsdroid.connector.gitlab.events import GitlabIssueCreated
+from opsdroid.events import Message
+
+class AlertTeam(Skill):
+    def __init__(self, opsdroid, config, *args, **kwargs):
+        super().__init__(opsdroid, config, *args, **kwargs)
+        self.opsdroid = opsdroid
+
+    @match_event(MRLabeled)
+    async def mr_labeled(self, event):
+        """Send message slack if MR was labeled as code-review."""
+        slack = self.opsdroid.get_connector("slack")
+        if "code-review" in event.labels:
+            await slack.send(
+                Message(
+                    text=f"Hey folks, the MR ({event.url}) was just marked as ready for review!",
+                )
+            )
+```
+
+This skill will trigger every time an MR gets labeled with something but only sends the message to the 
+Slack channel `#code-reviews` when the MR is labeled with the  `code-review` label.
+
+## Events Available
+
+Currently, the GitLab connector handles Merge Requests and Issues events, any other event such as pipeline events, for example, will be retured as `GenericGitlabEvent`.
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GenericGitlabEvent
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GitlabIssueCreated
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GitlabIssueClosed
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GitlabIssueEdited
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GitlabIssueLabeled
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GenericIssueEvent
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.MRCreated
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.MRMerged
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.MRClosed
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.MRLabeled
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.MRApproved
+    :members:
+```
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.events.GenericMREvent
+    :members:
+```
+
+## Reference
+
+This dataclass is used internally within the Gitlab connector, but is worth noting a few things here.
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.GitlabPayload
+    :members:
+```
+
+This is the Connector reference
+
+```eval_rst
+.. autoclass:: opsdroid.connector.gitlab.ConnectorGitlab
+    :members:
+```

docs/connectors/index.md

@@ -7,6 +7,7 @@ Connectors are modules which connect opsdroid to an external event source. This
    :maxdepth: 1
 
    facebook
+   gitlab
    github
    gitter
    mattermost

opsdroid/configuration/example_configuration.yaml

@@ -176,6 +176,12 @@ connectors:
 #    ssl-verify: false # default: true
 #    connect-timeout: 30 # default: 30
 #
+#  ##GitLab (core)
+#  gitlab:
+#    # Optional but recomended
+#    webhook-token: <your token>
+#    # Required if sending message to gitlab
+#    token: <personal access token>
 #  ## Github (core)
 #  github:
 #    # required

opsdroid/connector/gitlab/__init__.py

@@ -0,0 +1,2 @@
+"""Import Gitlab connector."""
+from .connector import ConnectorGitlab, GitlabPayload  # noqa: F401