Support STREAMING_API_BASE_URL in Helm Chart (#18408)

This adds a mastodon.streaming.base_url setting in the Helm chart values
file to allow setting the STREAMING_API_BASE_URL in the Mastodon environnment
config map.

chart/templates/configmap-env.yaml

@@ -83,6 +83,9 @@ data:
   SMTP_TLS: {{ .Values.mastodon.smtp.tls | quote }}
   {{- end }}
   STREAMING_CLUSTER_NUM: {{ .Values.mastodon.streaming.workers | quote }}
+  {{- if .Values.mastodon.streaming.base_url }}
+  STREAMING_API_BASE_URL: {{ .Values.mastodon.streaming.base_url | quote }}
+  {{- end }}
   {{- if .Values.externalAuth.oidc.enabled }}
   OIDC_ENABLED: {{ .Values.externalAuth.oidc.enabled | quote }}
   OIDC_DISPLAY_NAME: {{ .Values.externalAuth.oidc.display_name }}
@@ -300,4 +303,4 @@ data:
   {{- if .Values.externalAuth.ldap.uid_conversion.replace }}
   LDAP_UID_CONVERSION_REPLACE: {{ .Values.externalAuth.ldap.uid_conversion.replace }}
   {{- end }}
-  {{- end }}
+  {{- end }}
\ No newline at end of file

chart/values.yaml

@@ -83,6 +83,9 @@ mastodon:
     # the node running the pod, which is unrelated to the resources allocated to
     # the pod by k8s
     workers: 1
+    # The base url for streaming can be set if the streaming API is deployed to
+    # a different domain/subdomain.
+    # base_url: wws://streaming.example.com
   web:
     port: 3000