From 5825a0c9195b990b727d5c0d507671281f01da71 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julian-Samuel=20Geb=C3=BChr?= <julian-samuel@gebuehr.net>
Date: Fri, 9 Sep 2022 13:37:52 +0200
Subject: [PATCH] Cactus comments (#2089)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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* Add construct for cactus comments role

* Adjust config files

* Add docker self build to defaults

* Adjust tasks

* Fix smaller syntax errors

* Fix env argument

* Add tmp path to allow container writing there

Background why I did this: https://docs.gunicorn.org/en/stable/settings.html#worker-tmp-dir

* Change port back to 5000 as not configurable in container

* Try to add appservice config file for synapse to use

* Inject appservice file

* Correct copied variable name

* Comment out unused app service file injection

would need mounting the appservice file to the synapse container i guess

* Move role before synapse to be able to inject during runtime

* Remove unused parts

* Change default user id to mirror official docs

* Add docs

* Update roles/matrix-cactus-comments/tasks/setup_install.yml

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Update roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Generate secrets if necessary, adjust docs

* Rename cactusbot userid

* Shorten salt strings

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Use tmpfs instead of persistent mount

* Remove proxy option as it is nonsense

* Add download and serving of cc-client files

* Add documentation on client

* Clarify docs a bit

* Add nginx proxy to required services

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Use container address

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Correct comment of user id

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Use releases or local distributed client

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Move homeserver url to defaults

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Correct truth value

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Add documentation of variables

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Tabs vs. spaces

Co-authored-by: Slavi Pantaleev <slavi@devture.com>

* Make nginx root configurable

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Complete ake nginx root configurable

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Fix file permission

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

* Fix lint errors

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>

Signed-off-by: Julian-Samuel Gebühr <julian-samuel@gebuehr.net>
Co-authored-by: Slavi Pantaleev <slavi@devture.com>
---
 README.md                                     |   2 +
 docs/configuring-playbook-cactus-comments.md  |  63 ++++++++
 docs/configuring-playbook.md                  |   2 +
 docs/container-images.md                      |   2 +
 group_vars/matrix_servers                     |  29 ++++
 .../matrix-cactus-comments/defaults/main.yml  |  58 ++++++++
 roles/matrix-cactus-comments/tasks/init.yml   |  67 +++++++++
 roles/matrix-cactus-comments/tasks/main.yml   |  23 +++
 .../tasks/setup_install.yml                   | 138 ++++++++++++++++++
 .../tasks/setup_uninstall.yml                 |  36 +++++
 .../tasks/validate_config.yml                 |  10 ++
 .../templates/cactus_appservice.yaml.j2       |  19 +++
 roles/matrix-cactus-comments/templates/env.j2 |   6 +
 .../systemd/matrix-cactus-comments.service.j2 |  36 +++++
 setup.yml                                     |   1 +
 15 files changed, 492 insertions(+)
 create mode 100644 docs/configuring-playbook-cactus-comments.md
 create mode 100644 roles/matrix-cactus-comments/defaults/main.yml
 create mode 100644 roles/matrix-cactus-comments/tasks/init.yml
 create mode 100644 roles/matrix-cactus-comments/tasks/main.yml
 create mode 100644 roles/matrix-cactus-comments/tasks/setup_install.yml
 create mode 100644 roles/matrix-cactus-comments/tasks/setup_uninstall.yml
 create mode 100644 roles/matrix-cactus-comments/tasks/validate_config.yml
 create mode 100644 roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2
 create mode 100644 roles/matrix-cactus-comments/templates/env.j2
 create mode 100644 roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2

diff --git a/README.md b/README.md
index 221e8a85b..e545d18f0 100644
--- a/README.md
+++ b/README.md
@@ -137,6 +137,8 @@ Using this playbook, you can get the following services configured on your serve
 
 - (optional) the [Buscarron](https://gitlab.com/etke.cc/buscarron) bot - see [docs/configuring-playbook-bot-buscarron.md](docs/configuring-playbook-bot-buscarron.md) for setup documentation
 
+- (optional) [Cactus Comments](https://cactus.chat), a federated comment system built on matrix - see [docs/configuring-playbook-cactus-comments.md](docs/configuring-playbook-cactus-comments.md) for setup documentation
+
 Basically, this playbook aims to get you up-and-running with all the necessities around Matrix, without you having to do anything else.
 
 **Note**: the list above is exhaustive. It includes optional or even some advanced components that you will most likely not need.
diff --git a/docs/configuring-playbook-cactus-comments.md b/docs/configuring-playbook-cactus-comments.md
new file mode 100644
index 000000000..b62d33b27
--- /dev/null
+++ b/docs/configuring-playbook-cactus-comments.md
@@ -0,0 +1,63 @@
+# Setting up Cactus Comments (optional)
+
+The playbook can install and configure [Cactus Comments](https://cactus.chat) for you.
+
+Cactus Comments is a **federated comment system** built on Matrix. The role allows you to self-host the system.
+It respects your privacy, and puts you in control.
+
+See the project's [documentation](https://cactus.chat/docs/getting-started/introduction/) to learn what it
+does and why it might be useful to you.
+
+
+## Configuration
+
+Add the following block to your `vars.yaml` and make sure to exchange the tokens to randomly generated values.
+
+```ỳaml
+#################
+## Cactus Chat ##
+#################
+
+matrix_cactus_comments_enabled: true
+
+# To allow guest comments without users needing to log in, you need to have guest registration enabled.
+# To do this you need to uncomment one of the following lines (depending if you are using synapse or dentrite as a homeserver)
+# If you don't know which one you use: The default is synapse ;)
+# matrix_synapse_allow_guest_access: true
+# matrix_dentrite_allow_guest_access
+```
+
+## Installing
+
+After configuring the playbook, run the [installation](installing.md) command again:
+
+```
+ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start
+```
+
+
+## Usage
+
+To get started wit cactus comments message @bot.cactusbot:your-homeserver.com and type `help` to make sure it works.
+Then register a site by typing: `register <sitename>`. You will then be invited into a moderation room.
+Now you are good to go and can include the comment section on your website!
+
+**Careful:** To really make use of self-hosting you need change a few things in comparison to the official docs!
+
+Insert the following snippet into you page and make sure to replace `example.com` with your base domain!
+
+
+```html
+<script type="text/javascript" src="https://matrix.example.com/cactus-comments/cactus.js"></script>
+<link rel="stylesheet" href="https://matrix.example.com/cactus-comments/style.css" type="text/css">
+<div id="comment-section"></div>
+<script>
+initComments({
+  node: document.getElementById("comment-section"),
+  defaultHomeserverUrl: "https://matrix.example.com:8448",
+  serverName: "example.com",
+  siteName: "YourSiteName",
+  commentSectionId: "1"
+})
+</script>
+```
diff --git a/docs/configuring-playbook.md b/docs/configuring-playbook.md
index b3b44b5ff..b17f902f2 100644
--- a/docs/configuring-playbook.md
+++ b/docs/configuring-playbook.md
@@ -179,3 +179,5 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 - [Setting up the Sygnal push gateway](configuring-playbook-sygnal.md) (optional)
 
 - [Setting up the ntfy push notifications server](configuring-playbook-ntfy.md) (optional)
+
+- [Setting up a Cactus Comments server](configuring-playbook-cactus-comments.md) - a federated comment system built on Matrix (optional)
diff --git a/docs/container-images.md b/docs/container-images.md
index b16babff0..737a44578 100644
--- a/docs/container-images.md
+++ b/docs/container-images.md
@@ -117,3 +117,5 @@ These services are not part of our default installation, but can be enabled by [
 - [matrixdotorg/sygnal](https://hub.docker.com/r/matrixdotorg/sygnal/) - [Sygnal](https://github.com/matrix-org/sygnal) is a reference Push Gateway for Matrix
 
 - [binwiederhier/ntfy](https://hub.docker.com/r/binwiederhier/ntfy/) - [ntfy](https://ntfy.sh/) is a self-hosted, UnifiedPush-compatible push notifications server
+
+- [cactuscomments/cactus-appservice](https://hub.docker.com/r/cactuscomments/cactus-appservice/) - [Cactus Comments](https://cactus.chat) a federated comment system built on Matrix
diff --git a/group_vars/matrix_servers b/group_vars/matrix_servers
index 2c14a917f..d96af3630 100755
--- a/group_vars/matrix_servers
+++ b/group_vars/matrix_servers
@@ -1332,6 +1332,35 @@ matrix_backup_borg_systemd_required_services_list: |
 # /matrix-backup-borg
 #
 ######################################################################
+######################################################################
+#
+# matrix-cactus-comments
+#
+######################################################################
+
+matrix_cactus_comments_enabled: false
+
+# Derive secret values from homeserver secret
+matrix_cactus_comments_as_token: "{{ '%s' | format(matrix_homeserver_generic_secret_key) | password_hash('sha512', 'cactus.as.token') | to_uuid }}"
+matrix_cactus_comments_hs_token: "{{ '%s' | format(matrix_homeserver_generic_secret_key) | password_hash('sha512', 'cactus.hs.token') | to_uuid }}"
+
+matrix_cactus_comments_container_image_self_build: "{{ matrix_architecture not in ['amd64', 'arm32', 'arm64'] }}"
+matrix_cactus_comments_systemd_required_services_list: |
+  {{
+    (['docker.service'])
+    +
+    (['matrix-nginx-proxy.service'] if matrix_nginx_proxy_enabled else [])
+    +
+    (['matrix-' + matrix_homeserver_implementation + '.service'])
+  }}
+
+matrix_cactus_comments_client_nginx_path: {{ '/cactus-comments/' if matrix_nginx_proxy_enabled else matrix_cactus_comments_client_path + '/' }}
+
+######################################################################
+#
+# /matrix-cactus-comments
+#
+######################################################################
 
 ######################################################################
 #
diff --git a/roles/matrix-cactus-comments/defaults/main.yml b/roles/matrix-cactus-comments/defaults/main.yml
new file mode 100644
index 000000000..dbd5b8441
--- /dev/null
+++ b/roles/matrix-cactus-comments/defaults/main.yml
@@ -0,0 +1,58 @@
+---
+# Cactus Comments is a federated comment system built on Matrix
+
+matrix_cactus_comments_enabled: true
+matrix_cactus_comments_serve_client_enabled: true
+matrix_cactus_comments_container_image_self_build: false
+matrix_cactus_comments_docker_repo: "https://gitlab.com/cactus-comments/cactus-appservice.git"
+matrix_cactus_comments_docker_repo_version: "{{ matrix_cactus_comments_version if matrix_cactus_comments_version != 'latest' else 'main' }}"
+matrix_cactus_comments_docker_src_files_path: "{{ matrix_cactus_comments_base_path }}/docker-src"
+
+
+matrix_cactus_comments_base_path: "{{ matrix_base_data_path }}/cactus-comments"
+matrix_cactus_comments_container_tmp_path: "{{ matrix_cactus_comments_base_path }}/tmp"
+matrix_cactus_comments_client_path: "{{ matrix_cactus_comments_base_path }}/client"
+matrix_cactus_comments_client_file_permissions: "0644"
+
+matrix_cactus_comments_app_service_config_file: "{{ matrix_cactus_comments_base_path }}/cactus_appservice.yaml"
+matrix_cactus_comments_app_service_env_file: "{{ matrix_cactus_comments_base_path }}/cactus.env"
+
+matrix_cactus_comments_as_token: ''
+matrix_cactus_comments_hs_token: ''
+matrix_cactus_comments_homeserver_url: "{{ matrix_homeserver_container_url }}"
+matrix_cactus_comments_user_id: "bot.cactusbot"
+matrix_cactus_comments_tmp_directory_size_mb: 1
+
+matrix_cactus_comments_container_port: 5000
+
+matrix_cactus_comments_version: latest
+matrix_cactus_comments_docker_image: "{{ matrix_container_global_registry_prefix }}cactuscomments/cactus-appservice:{{ matrix_cactus_comments_version }}"
+matrix_cactus_comments_docker_image_force_pull: "{{ matrix_cactus_comments_docker_image.endswith(':latest') }}"
+
+# matrix_cactus_comments_client_version specifies the version of the cactus-client release to use.
+# For available versions, see: https://gitlab.com/cactus-comments/cactus-client/-/releases
+# Also see: `matrix_cactus_comments_client_local_dir`
+matrix_cactus_comments_client_version: "0.13.0"
+
+# matrix_cactus_comments_client_local_dir specifies a local directory (on the Ansible controller, not on the remote server) with cactus-client files to use.
+# This is an alternative to `matrix_cactus_comments_client_version`, to be used when you'd like to
+# provide the files locally / manually.
+matrix_cactus_comments_client_local_dir: ''
+
+# matrix_cactus_comments_client_nginx_path specifies the path where nginx can access the client files.
+# The default value assumes a container setup. If you're running nginx without a container, consider adjusting this path
+matrix_cactus_comments_client_nginx_path: "/cactus-comments/"
+
+# matrix_cactus_comments_client_endpoint specifies where nginx will serve the files in nginx is enabled
+matrix_cactus_comments_client_endpoint: "/cactus-comments/"
+
+# List of systemd services that matrix-cactus-comments.service depends on
+matrix_bot_cactus_comments_systemd_required_services_list: ['docker.service']
+
+# List of systemd services that matrix-cactus-comments.service wants
+matrix_bot_cactus_comments_systemd_wanted_services_list: []
+
+# A list of extra arguments to pass to the container
+matrix_cactus_comments_container_extra_arguments: []
+
+matrix_cactus_comments_environment_variables_extension: ''
diff --git a/roles/matrix-cactus-comments/tasks/init.yml b/roles/matrix-cactus-comments/tasks/init.yml
new file mode 100644
index 000000000..78cdd319d
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/init.yml
@@ -0,0 +1,67 @@
+---
+
+- ansible.builtin.set_fact:
+    matrix_systemd_services_list: "{{ matrix_systemd_services_list + ['matrix-cactus-comments.service'] }}"
+  when: matrix_cactus_comments_enabled | bool
+
+# If the matrix-synapse role is not used, these variables may not exist.
+- ansible.builtin.set_fact:
+    matrix_homeserver_container_runtime_injected_arguments: >
+      {{
+        matrix_homeserver_container_runtime_injected_arguments | default([])
+        +
+        ["--mount type=bind,src={{ matrix_cactus_comments_app_service_config_file }},dst=/matrix-cactus-comments.yaml,ro"]
+      }}
+
+    matrix_homeserver_app_service_runtime_injected_config_files: >
+      {{
+        matrix_homeserver_app_service_runtime_injected_config_files | default([])
+        +
+        ["/matrix-cactus-comments.yaml"]
+      }}
+  when: matrix_cactus_comments_enabled | bool
+
+- block:
+    - name: Fail if matrix-nginx-proxy role already executed
+      ansible.builtin.fail:
+        msg: >-
+          Trying to append Cactus Comment's reverse-proxying configuration to matrix-nginx-proxy,
+          but it's pointless since the matrix-nginx-proxy role had already executed.
+          To fix this, please change the order of roles in your playbook,
+          so that the matrix-nginx-proxy role would run after the matrix-cactus-comments role.
+      when: matrix_nginx_proxy_role_executed | default(False) | bool
+
+    - name: Mount volume
+      ansible.builtin.set_fact:
+        matrix_nginx_proxy_container_additional_volumes: >
+          {{
+                    matrix_nginx_proxy_container_additional_volumes | default([])
+            +
+            [{"src": "{{ matrix_cactus_comments_client_path }}", "dst": "/cactus-comments/cactus-comments", "options": "ro"}]
+          }}
+    - name: Generate Cactus Comment proxying configuration for matrix-nginx-proxy
+      ansible.builtin.set_fact:
+        matrix_cactus_comments_nginx_proxy_configuration: |
+          location {{ matrix_cactus_comments_client_endpoint }} {
+              root {{ matrix_cactus_comments_client_nginx_path }};
+          }
+      when: "matrix_nginx_proxy_enabled | default(False) | bool"
+    - name: Register Cactus Comment proxying configuration with matrix-nginx-proxy
+      ansible.builtin.set_fact:
+        matrix_nginx_proxy_proxy_matrix_additional_server_configuration_blocks: |
+          {{
+            matrix_nginx_proxy_proxy_matrix_additional_server_configuration_blocks | default([])
+            +
+            [matrix_cactus_comments_nginx_proxy_configuration]
+          }}
+    - name: Warn about reverse-proxying if matrix-nginx-proxy not used
+      ansible.builtin.debug:
+        msg: >-
+          NOTE: You've enabled Cactus Comments but are not using the matrix-nginx-proxy
+          reverse proxy.
+          Please make sure that you're proxying client files in {{ matrix_cactus_comments_client_path }} correctly
+      when: "not matrix_nginx_proxy_enabled | default(False) | bool"
+
+  tags:
+    - always
+  when: matrix_cactus_comments_enabled | bool and matrix_cactus_comments_serve_client_enabled | bool
diff --git a/roles/matrix-cactus-comments/tasks/main.yml b/roles/matrix-cactus-comments/tasks/main.yml
new file mode 100644
index 000000000..857e2db19
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/main.yml
@@ -0,0 +1,23 @@
+---
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/init.yml"
+  tags:
+    - always
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/validate_config.yml"
+  when: "run_setup | bool and matrix_cactus_comments_enabled | bool"
+  tags:
+    - setup-all
+    - setup-cactus-comments
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/setup_install.yml"
+  when: "run_setup | bool and matrix_cactus_comments_enabled | bool"
+  tags:
+    - setup-all
+    - setup-cactus-comments
+
+- ansible.builtin.import_tasks: "{{ role_path }}/tasks/setup_uninstall.yml"
+  when: "run_setup | bool and not matrix_cactus_comments_enabled | bool"
+  tags:
+    - setup-all
+    - setup-cactus-comments
diff --git a/roles/matrix-cactus-comments/tasks/setup_install.yml b/roles/matrix-cactus-comments/tasks/setup_install.yml
new file mode 100644
index 000000000..8e6bb68ed
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/setup_install.yml
@@ -0,0 +1,138 @@
+---
+
+- name: Ensure cactus comments paths exist
+  ansible.builtin.file:
+    path: "{{ item.path }}"
+    state: directory
+    mode: 0750
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  with_items:
+    - {path: "{{ matrix_cactus_comments_base_path }}", when: true}
+    - {path: "{{ matrix_cactus_comments_client_path }}", when: true}
+    - {path: "{{ matrix_cactus_comments_container_tmp_path }}", when: true}
+    - {path: "{{ matrix_cactus_comments_docker_src_files_path }}", when: matrix_cactus_comments_container_image_self_build}
+  when: "item.when | bool"
+
+- name: Ensure cactus comments environment file created
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/env.j2"
+    dest: "{{ matrix_cactus_comments_app_service_env_file }}"
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+    mode: 0640
+
+- name: Ensure cactus comments appservice file created
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/cactus_appservice.yaml.j2"
+    dest: "{{ matrix_cactus_comments_app_service_config_file }}"
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+    mode: 0640
+
+- name: Ensure cactus comments image is pulled
+  docker_image:
+    name: "{{ matrix_cactus_comments_docker_image }}"
+    source: "{{ 'pull' if ansible_version.major > 2 or ansible_version.minor > 7 else omit }}"
+    force_source: "{{ matrix_cactus_comments_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_cactus_comments_docker_image_force_pull }}"
+  when: "not matrix_cactus_comments_container_image_self_build | bool"
+  register: result
+  retries: "{{ matrix_container_retries_count }}"
+  delay: "{{ matrix_container_retries_delay }}"
+  until: result is not failed
+
+- name: Ensure cactus comments repository is present on self-build
+  ansible.builtin.git:
+    repo: "{{ matrix_cactus_comments_docker_repo }}"
+    version: "{{ matrix_cactus_comments_docker_repo_version }}"
+    dest: "{{ matrix_cactus_comments_docker_src_files_path }}"
+    force: "yes"
+  become: true
+  become_user: "{{ matrix_user_username }}"
+  register: matrix_cactus_comments_git_pull_results
+  when: "matrix_cactus_comments_container_image_self_build | bool"
+
+- name: Ensure cactus comments image is built
+  docker_image:
+    name: "{{ matrix_cactus_comments_docker_image }}"
+    source: build
+    force_source: "{{ matrix_cactus_comments_git_pull_results.changed if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_mailer_git_pull_results.changed }}"
+    build:
+      dockerfile: Dockerfile
+      path: "{{ matrix_cactus_comments_docker_src_files_path }}"
+      pull: true
+  when: "matrix_cactus_comments_container_image_self_build | bool"
+
+- block:
+    - name: Download client binary to local folder
+      ansible.builtin.get_url:
+        url: "https://gitlab.com/cactus-comments/cactus-client/-/archive/v{{ matrix_cactus_comments_client_version }}/cactus-client-v{{ matrix_cactus_comments_client_version }}.tar.gz"
+        dest: "/tmp/cactus-comments-{{ matrix_cactus_comments_client_version }}.tar.gz"
+        mode: '0644'
+      register: _download_client
+      until: _download_client is succeeded
+      retries: 5
+      delay: 2
+      check_mode: false
+
+    - name: Unpack client
+      ansible.builtin.unarchive:
+        src: "/tmp/cactus-comments-{{ matrix_cactus_comments_client_version }}.tar.gz"
+        dest: "/tmp/"
+        remote_src: true
+        mode: 0600
+      check_mode: false
+
+    - name: Propagate client javascript file
+      ansible.builtin.copy:
+        src: "/tmp/cactus-client-v{{ matrix_cactus_comments_client_version }}/src/cactus.js"
+        remote_src: true
+        dest: "{{ matrix_cactus_comments_client_path }}/cactus.js"
+        mode: "{{ matrix_cactus_comments_client_file_permissions }}"
+        owner: "{{ matrix_user_username }}"
+        group: "{{ matrix_user_groupname }}"
+    - name: Propagate client style file
+      ansible.builtin.copy:
+        src: "/tmp/cactus-client-v{{ matrix_cactus_comments_client_version }}/src/style.css"
+        remote_src: true
+        dest: "{{ matrix_cactus_comments_client_path }}/style.css"
+        mode: "{{ matrix_cactus_comments_client_file_permissions }}"
+        owner: "{{ matrix_user_username }}"
+        group: "{{ matrix_user_groupname }}"
+  when: matrix_cactus_comments_client_local_dir | length == 0
+
+- block:
+    - name: Propagate locally distributed client javascreipt
+      ansible.builtin.copy:
+        src: "{{ matrix_cactus_comments_client_local_dir }}/src/cactus.js"
+        dest: "{{ matrix_cactus_comments_client_path }}/cactus.js"
+        mode: "{{ matrix_cactus_comments_client_file_permissions }}"
+        owner: "{{ matrix_user_username }}"
+        group: "{{ matrix_user_groupname }}"
+    - name: Propagate locally distributed client style.css
+      ansible.builtin.copy:
+        src: "{{ matrix_cactus_comments_client_local_dir }}/src/style.css"
+        dest: "{{ matrix_cactus_comments_client_path }}/style.css"
+        mode: "{{ matrix_cactus_comments_client_file_permissions }}"
+        owner: "{{ matrix_user_username }}"
+        group: "{{ matrix_user_groupname }}"
+  when: matrix_cactus_comments_client_local_dir | length > 0
+
+- name: Ensure matrix-cactus-comments.service installed
+  ansible.builtin.template:
+    src: "{{ role_path }}/templates/systemd/matrix-cactus-comments.service.j2"
+    dest: "{{ matrix_systemd_path }}/matrix-cactus-comments.service"
+    mode: 0644
+  register: matrix_cactus_comments_systemd_service_result
+
+- name: Ensure systemd reloaded after matrix-cactus-comments.service installation
+  ansible.builtin.service:
+    daemon_reload: true
+  when: "matrix_cactus_comments_systemd_service_result.changed | bool"
+
+- name: Ensure matrix-cactus-comments.service restarted, if necessary
+  ansible.builtin.service:
+    name: "matrix-cactus-comments.service"
+    state: restarted
diff --git a/roles/matrix-cactus-comments/tasks/setup_uninstall.yml b/roles/matrix-cactus-comments/tasks/setup_uninstall.yml
new file mode 100644
index 000000000..011c04b85
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/setup_uninstall.yml
@@ -0,0 +1,36 @@
+---
+
+- name: Check existence of matrix-cactus-comments service
+  ansible.builtin.stat:
+    path: "{{ matrix_systemd_path }}/matrix-cactus-comments.service"
+  register: matrix_cactus_comments_service_stat
+
+- name: Ensure cactus comments is stopped
+  ansible.builtin.service:
+    name: matrix-cactus-comments
+    state: stopped
+    enabled: false
+    daemon_reload: true
+  register: stopping_result
+  when: "matrix_cactus_comments_service_stat.stat.exists | bool"
+
+- name: Ensure matrix-cactus-comments.service doesn't exist
+  ansible.builtin.file:
+    path: "{{ matrix_systemd_path }}/matrix-cactus-comments.service"
+    state: absent
+  when: "matrix_cactus_comments_service_stat.stat.exists | bool"
+
+- name: Ensure systemd reloaded after matrix-cactus-comments.service removal
+  ansible.builtin.service:
+    daemon_reload: true
+  when: "matrix_cactus_comments_service_stat.stat.exists | bool"
+
+- name: Ensure Matrix cactus comments paths don't exist
+  ansible.builtin.file:
+    path: "{{ matrix_cactus_comments_base_path }}"
+    state: absent
+
+- name: Ensure cactus comments Docker image doesn't exist
+  docker_image:
+    name: "{{ matrix_cactus_comments_docker_image }}"
+    state: absent
diff --git a/roles/matrix-cactus-comments/tasks/validate_config.yml b/roles/matrix-cactus-comments/tasks/validate_config.yml
new file mode 100644
index 000000000..094a203df
--- /dev/null
+++ b/roles/matrix-cactus-comments/tasks/validate_config.yml
@@ -0,0 +1,10 @@
+---
+
+- name: Fail if required settings not defined
+  ansible.builtin.fail:
+    msg: >-
+      You need to define a required configuration setting (`{{ item }}`).
+  when: "vars[item] == ''"
+  with_items:
+    - "matrix_cactus_comments_as_token"
+    - "matrix_cactus_comments_hs_token"
diff --git a/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2 b/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2
new file mode 100644
index 000000000..bfcb4bb36
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/cactus_appservice.yaml.j2
@@ -0,0 +1,19 @@
+# A unique, user-defined ID of the application service which will never change.
+id: "Cactus Comments"
+
+# Where the cactus-appservice is hosted:
+url: "http://matrix-cactus-comments:{{ matrix_cactus_comments_container_port }}"
+
+# Unique tokens used to authenticate requests between our service and the
+# homeserver (and the other way). Use the sha256 hashes of something random.
+# CHANGE THESE VALUES.
+as_token: {{ matrix_cactus_comments_as_token | to_json }}
+hs_token: {{ matrix_cactus_comments_hs_token | to_json }}
+
+# The user id of the cactusbot which can be used to register and moderate sites
+sender_localpart: "{{ matrix_cactus_comments_user_id }}"
+
+namespaces:
+  aliases:
+    - exclusive: true
+      regex: "#comments_.*"
diff --git a/roles/matrix-cactus-comments/templates/env.j2 b/roles/matrix-cactus-comments/templates/env.j2
new file mode 100644
index 000000000..ab0489612
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/env.j2
@@ -0,0 +1,6 @@
+CACTUS_HS_TOKEN={{ matrix_cactus_comments_hs_token }}
+CACTUS_AS_TOKEN={{ matrix_cactus_comments_as_token }}
+CACTUS_HOMESERVER_URL={{ matrix_cactus_comments_homeserver_url }}
+CACTUS_USER_ID=@{{ matrix_cactus_comments_user_id }}:{{ matrix_domain }}
+
+{{ matrix_cactus_comments_environment_variables_extension }}
diff --git a/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2 b/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2
new file mode 100644
index 000000000..068255823
--- /dev/null
+++ b/roles/matrix-cactus-comments/templates/systemd/matrix-cactus-comments.service.j2
@@ -0,0 +1,36 @@
+#jinja2: lstrip_blocks: "True"
+[Unit]
+Description=Cactus Comments
+{% for service in matrix_bot_cactus_comments_systemd_required_services_list %}
+Requires={{ service }}
+After={{ service }}
+{% endfor %}
+{% for service in matrix_bot_cactus_comments_systemd_wanted_services_list %}
+Wants={{ service }}
+{% endfor %}
+DefaultDependencies=no
+
+[Service]
+Type=simple
+Environment="HOME={{ matrix_systemd_unit_home_path }}"
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-cactus-comments 2>/dev/null || true'
+ExecStartPre=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-cactus-comments 2>/dev/null || true'
+
+ExecStart={{ matrix_host_command_docker }} run --rm --name matrix-cactus-comments \
+			--log-driver=none \
+			--cap-drop=ALL \
+			--user={{ matrix_user_uid }}:{{ matrix_user_gid }} \
+			--read-only \
+			--env-file {{ matrix_cactus_comments_app_service_env_file }} \
+			--tmpfs=/tmp:rw,noexec,nosuid,size={{ matrix_cactus_comments_tmp_directory_size_mb }}m \
+			--network={{ matrix_docker_network }} \
+			{{ matrix_cactus_comments_docker_image }}
+
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} kill matrix-cactus-comments 2>/dev/null || true'
+ExecStop=-{{ matrix_host_command_sh }} -c '{{ matrix_host_command_docker }} rm matrix-cactus-comments 2>/dev/null || true'
+Restart=always
+RestartSec=30
+SyslogIdentifier=matrix-cactus-comments
+
+[Install]
+WantedBy=multi-user.target
diff --git a/setup.yml b/setup.yml
index 3b7d235d3..bd78158cd 100755
--- a/setup.yml
+++ b/setup.yml
@@ -46,6 +46,7 @@
     - matrix-bot-postmoogle
     - matrix-bot-go-neb
     - matrix-bot-mjolnir
+    - matrix-cactus-comments
     - matrix-synapse
     - matrix-dendrite
     - matrix-conduit