feat: add NATS executor

.gitignore

@@ -27,3 +27,4 @@ tests/pki_variables.yml
 *.xml
 test_results*.html
 !venom_output.html
+tests/nats/pki

executors/nats/README.md

@@ -0,0 +1,122 @@
+# Venom - Executor NATS
+
+Step to publish and subscribe to NATS subjects.
+
+Currently two commands are supported:
+
+- `publish`
+- `subscribe`
+
+## Input
+
+### Defaults
+
+This step includes some default values:
+
+- `url`: defaults to `nats://localhost:4222`
+- `messageLimit`: defaults to 1
+- `deadline`: defaults to 1 second
+
+### Authentication
+
+This step allows for connection with and without TLS. Without TLS, the step does not require additional options.
+
+To connect to a NATS server with TLS, declare:
+
+```yaml
+tls:
+  selfSigned: true
+  serverVerify: true
+  certificatePath: "/path/to/client_certificate"
+  keyPath: "/path/to/client_key"
+  caPath: ""/path/to/ca_certificate""
+```
+
+Enable `selfSigned` only if the NATS server uses self-signed certificates. If enabled, `caPath` is mandatory.
+
+Enable `serverVerify` only if the NATS server verifies the client certificates. If enabled `certificatePath` and `keyPath` are mandatory.
+
+### publish command
+
+The `publish` command allows to publish a payload to a specific NATS subject. Optionally it can wait for a reply.
+
+Full configuration example:
+
+```yaml
+- type: nats
+  url: "{{.url}}" # defaults to nats://localhost:4222 if not set
+  command: publish
+  subject: "{{.subject}}" # mandatory
+  payload: '{{.message}}'
+  headers:
+    customHeader:
+      - "some-value"
+  assertions:
+    - result.error ShouldBeEmpty
+```
+
+Full configuration with reply example:
+
+```yaml
+- type: nats
+  url: "{{.url}}" # defaults to nats://localhost:4222 if not set
+  command: publish
+  request: true
+  subject: "{{.subject}}" # mandatory
+  replySubject: "{{.subject}}.reply" # mandatory if `request = true`
+  payload: '{{.message}}'
+  assertions:
+    - result.error ShouldBeEmpty
+    - result.messages.__Len__ ShouldEqual 1
+```
+
+It is possible to publish to a Jetstream stream by declaring `jetstream: true` in the step.
+
+ For example:
+
+```yaml
+- type: nats
+  command: publish
+  subject: "{{.subject}}.hello" # mandatory
+  deadline: 2
+  jetstream:
+    enabled: true
+  assertions:
+    - result.error ShouldNotBeEmpty
+```
+
+### subscribe command
+
+The `subscribe` command allows to receive messages from a subject or a stream.
+
+Full configuration example:
+
+```yaml
+- type: nats
+  command: subscribe
+  subject: "{{.subject}}.>" # mandatory
+  messageLimit: 2 # defaults to 1
+  deadline: 10 # in seconds, defaults to 1
+  assertions:
+    - result.error ShouldBeEmpty
+    - result.messages.__Len__ ShouldEqual 2
+```
+
+Full configuration example with Jetstream:
+
+```yaml
+- type: nats
+  command: subscribe
+  subject: "{{.subject}}.>" # mandatory
+  messageLimit: 2 # defaults to 1
+  deadline: 10 # in seconds, defaults to 1
+  jetstream:
+    enabled: true
+    stream: TEST # mandatory, stream must exist
+    filterSubjects:
+      - "{{.subject}}.js.hello"
+      - "{{.subject}}.js.world"
+  assertions:
+    - result.error ShouldBeEmpty
+    - result.messages.__Len__ ShouldEqual 2
+```