Add `state` option for removing exporters

10 files changed, 142 insertions, 13 deletions

diff --git a/README.md b/README.md
index 32d85c8..5e5ce86 100644
--- a/README.md
+++ b/README.md
@@ -52,6 +52,7 @@ prometheus_target_exporter_defaults: {}
   # node_exporter:
   #   path: /opt/prometheus/targets.yml
   #   host: '{{ inventory_hostname }}:9100'
+  #   state: present
   #   labels:  # Labels to match when using yaml strategy
   #     severity: warning
   #     job: external
@@ -65,6 +66,17 @@ prometheus_target_exporter_defaults: {}
 prometheus_target_exporter: []
 ```
 
+Each exporter accepts `state: present` or `state: absent`, defaulting to
+`present`. Set `state: absent` to remove the rendered target from its target
+file. The setting can be defined in `prometheus_target_exporter_defaults` and
+overridden by an entry in `prometheus_target_exporter`.
+
+With the `yaml` strategy, removal searches every group in the configured file,
+regardless of the exporter's labels, and removes groups left without targets.
+With the `lineinfile` strategy, removal deletes the exact line produced by the
+configured prefix, host, and suffix. Removing a target from a missing file is a
+no-op for both strategies.
+
 You can also add exporter that you want to have deployed without needing to
 specify them in the `prometheus_target_exporter` variable by adding them to the
 `prometheus_target_default_exporters` variable.
diff --git a/defaults/main.yml b/defaults/main.yml
index 2b62d46..f253626 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -129,12 +129,14 @@ prometheus_target_exporter_defaults: {}
   #   labels:  # Labels to match when using yaml strategy
   #     severity: warning
   #     job: external
+  #   state: present  # Set to absent to remove this target
   # blackbox_exporter:
   #   path: /opt/targets/blackbox.yml
   #   host: "https://{{ hostvars[inventory_hostname].ansible_host }}"
   #   path_prefix: ""
   #   labels:
   #     severity: critical
+  #   state: present
 
 # This is where you specify the exporters that should be deployed to prometheus.
 # You should configure this on a per play basis. If you wish to configure
@@ -150,6 +152,7 @@ prometheus_target_exporter: []
   #   labels:
   #     severity: warning
   #     job: external
+  #   state: present  # Set to absent to remove this target
 
 # This is a list of exporters that will be appended to the
 # prometheus_target_exporter variable. duplicate exporters in
diff --git a/meta/argument_specs.yml b/meta/argument_specs.yml
index b35c993..f0477a9 100644
--- a/meta/argument_specs.yml
+++ b/meta/argument_specs.yml
@@ -121,6 +121,13 @@ argument_specs:
             type: dict
             required: false
             description: Labels to match the target group in the YAML file (yaml strategy only)
+          state:
+            type: str
+            required: false
+            default: present
+            choices:
+              - present
+              - absent
 
       prometheus_target_default_exporters:
         type: list
@@ -144,6 +151,13 @@ argument_specs:
             type: dict
             required: false
             description: Labels to match the target group in the YAML file (yaml strategy only)
+          state:
+            type: str
+            required: false
+            default: present
+            choices:
+              - present
+              - absent
 
       prometheus_target_skip_default_exporters:
         type: bool
diff --git a/molecule/default/converge.yml b/molecule/default/converge.yml
index 59d63bc..8e0b5c9 100644
--- a/molecule/default/converge.yml
+++ b/molecule/default/converge.yml
@@ -743,3 +743,51 @@
       prometheus_target_exporter:
         - path: /opt/handler_disabled.yml
           host: application
+
+################################################################################
+################################################################################
+- name: Remove lineinfile exporters
+  hosts: application_remove
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_strategy_lineinfile_prefix: "    - "
+    prometheus_target_exporter_defaults:
+      remove_shared:
+        path: /opt/lineinfile_state_removal.yml
+        host: remove:9100
+        state: absent
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_exporter:
+        - id: remove_shared
+        - path: /opt/lineinfile_state_removal.yml
+          host: remove:9200
+          state: absent
+        - path: /opt/lineinfile_state_missing.yml
+          host: missing:9100
+          state: absent
+
+################################################################################
+################################################################################
+- name: Remove YAML exporters
+  hosts: application_remove
+  vars:
+    prometheus_target_host: prometheus
+    prometheus_target_strategy: yaml
+    prometheus_target_exporter_defaults:
+      remove_shared:
+        path: /opt/yaml_state_removal.yml
+        host: remove:9100
+        state: absent
+
+  roles:
+    - role: kliwniloc.prometheus_target
+      prometheus_target_exporter:
+        - id: remove_shared
+        - path: /opt/yaml_state_removal.yml
+          host: remove:9200
+          state: absent
+        - path: /opt/yaml_state_missing.yml
+          host: missing:9100
+          state: absent
diff --git a/molecule/default/molecule.yml b/molecule/default/molecule.yml
index 04d4391..bdc5df7 100644
--- a/molecule/default/molecule.yml
+++ b/molecule/default/molecule.yml
@@ -43,6 +43,13 @@ platforms:
       - name: molecule-container-net
     groups: [application_group]
 
+  - name: application_remove
+    image: ${MOLECULE_DISTRO:-debian:12}
+    dockerfile: Dockerfile.j2
+    pre_build_image: false
+    networks:
+      - name: molecule-container-net
+
   - name: prometheus
     image: ${MOLECULE_DISTRO:-debian:12}
     dockerfile: Dockerfile.j2
diff --git a/molecule/default/tests/test_lineinfile_strategy.py b/molecule/default/tests/test_lineinfile_strategy.py
index 770459e..d7f9738 100644
--- a/molecule/default/tests/test_lineinfile_strategy.py
+++ b/molecule/default/tests/test_lineinfile_strategy.py
@@ -122,11 +122,12 @@ def test_disabled_handlers_do_not_run(host):
     assert not host.file("/tmp/disabled-shell-handler").exists
 
 
-def test_future_lineinfile_removal_fixture_is_untouched(host):
+def test_lineinfile_absent_removes_exporters(host):
     assert read_yaml_file(host, "/opt/lineinfile_state_removal.yml") == [
         {
             "labels": {"job": "shared"},
-            "targets": ["keep:9100", "remove:9100"],
+            "targets": ["keep:9100"],
         },
-        {"labels": {"job": "remove_last"}, "targets": ["remove:9200"]},
+        {"labels": {"job": "remove_last"}, "targets": None},
     ]
+    assert not host.file("/opt/lineinfile_state_missing.yml").exists
diff --git a/molecule/default/tests/test_yaml_strategy.py b/molecule/default/tests/test_yaml_strategy.py
index c3d0dd9..7f9b6ed 100644
--- a/molecule/default/tests/test_yaml_strategy.py
+++ b/molecule/default/tests/test_yaml_strategy.py
@@ -197,11 +197,11 @@ def test_yaml_skip_default_exporters(host):
     assert target.content_string == ""
 
 
-def test_future_yaml_removal_fixture_is_untouched(host):
+def test_yaml_absent_removes_exporters_and_empty_groups(host):
     assert read_yaml_file(host, "/opt/yaml_state_removal.yml") == [
         {
             "labels": {"job": "shared"},
-            "targets": ["keep:9100", "remove:9100"],
+            "targets": ["keep:9100"],
         },
-        {"labels": {"job": "remove_last"}, "targets": ["remove:9200"]},
     ]
+    assert not host.file("/opt/yaml_state_missing.yml").exists
diff --git a/tasks/process_exporter.yml b/tasks/process_exporter.yml
index b4f33ba..0a19480 100644
--- a/tasks/process_exporter.yml
+++ b/tasks/process_exporter.yml
@@ -12,6 +12,13 @@
       {{ (item.host if item.host is defined else _defaults.host) | mandatory }}
     _target_labels: >-
       {{ (_defaults.labels | default({})) | combine(item.labels | default({})) }}
+    _target_state: >-
+      {{ item.state if item.state is defined else (_defaults.state | default('present')) }}
+
+- name: Validate exporter state
+  ansible.builtin.assert:
+    that: _target_state in ["present", "absent"]
+    fail_msg: "Exporter state must be 'present' or 'absent', got '{{ _target_state }}'"
 
 - name: Execute strategy
   ansible.builtin.include_tasks:
diff --git a/tasks/strategy_lineinfile.yml b/tasks/strategy_lineinfile.yml
index 7656602..2b2d02a 100644
--- a/tasks/strategy_lineinfile.yml
+++ b/tasks/strategy_lineinfile.yml
@@ -1,13 +1,23 @@
 ---
+- name: Check target file for removal
+  ansible.builtin.stat:
+    path: "{{ _target_path }}"
+  delegate_to: "{{ prometheus_target_host }}"
+  become: true
+  register: _target_file
+  when: _target_state == "absent"
+
 - name: Deploy target via lineinfile
   ansible.builtin.lineinfile:
     path: "{{ _target_path }}"
     line: "{{ prometheus_target_strategy_lineinfile_prefix ~ _target_host ~ prometheus_target_strategy_lineinfile_suffix }}"
-    state: present
+    state: "{{ _target_state }}"
   delegate_to: "{{ prometheus_target_host }}"
   become: true
   register: _lineinfile_result
+  when: _target_state == "present" or _target_file.stat.exists
 
 - name: Track changes
   ansible.builtin.set_fact:
-    changed: "{{ changed | default(false) or _lineinfile_result.changed }}"
+    changed: >-
+      {{ changed | default(false) or (_lineinfile_result.changed | default(false)) }}
diff --git a/tasks/strategy_yaml.yml b/tasks/strategy_yaml.yml
index 24cd6c8..45b18c3 100644
--- a/tasks/strategy_yaml.yml
+++ b/tasks/strategy_yaml.yml
@@ -14,10 +14,22 @@
             ((exporter.path if exporter.path is defined else defaults.path) | mandatory) -%}
         {%- set host = (exporter.host if exporter.host is defined else defaults.host) | mandatory -%}
         {%- set labels = (defaults.labels | default({})) | combine(exporter.labels | default({})) -%}
-        {%- set _ = ns.updates.append({'path': path, 'host': host, 'labels': labels}) -%}
+        {%- set target_state = exporter.state if exporter.state is defined else
+            (defaults.state | default('present')) -%}
+        {%- set _ = ns.updates.append(
+            {'path': path, 'host': host, 'labels': labels, 'state': target_state}) -%}
       {%- endfor -%}
       {{ ns.updates }}
 
+- name: Validate YAML exporter states
+  ansible.builtin.assert:
+    that: _yaml_update.state in ["present", "absent"]
+    fail_msg: "Exporter state must be 'present' or 'absent', got '{{ _yaml_update.state }}'"
+  loop: "{{ _prometheus_target_yaml_updates }}"
+  loop_control:
+    loop_var: _yaml_update
+    label: "{{ _yaml_update.path }}"
+
 # Every play host prepares its values above. Applying all updates from one host
 # prevents parallel Ansible forks from overwriting each other's YAML changes.
 - name: Aggregate YAML exporter updates
@@ -56,14 +68,27 @@
     _prometheus_target_yaml_files: >-
       {%- set output = namespace(files=[]) -%}
       {%- for file in _yaml_target_files.results -%}
+        {%- set file_updates = _prometheus_target_yaml_updates_all |
+            selectattr('path', 'equalto', file._yaml_path) | list -%}
+        {%- set present_updates = file_updates |
+            selectattr('state', 'equalto', 'present') | list -%}
         {%- set state = namespace(groups=(file.content | b64decode | from_yaml)
             if file.content is defined else []) -%}
         {%- set state.groups = state.groups if state.groups is not none else [] -%}
-        {%- for update in _prometheus_target_yaml_updates_all if update.path == file._yaml_path -%}
+        {%- for update in file_updates -%}
           {%- set next = namespace(found=false, groups=[]) -%}
           {%- for group in state.groups -%}
             {%- set group_labels = group.labels | default({}) -%}
-            {%- if group_labels == update.labels -%}
+            {%- if update.state == 'absent' -%}
+              {%- set filtered = group.targets | reject('equalto', update.host) | list -%}
+              {%- if filtered | length > 0 -%}
+                {%- set replacement = {'targets': filtered} -%}
+                {%- if group_labels | length > 0 -%}
+                  {%- set _ = replacement.update({'labels': group_labels}) -%}
+                {%- endif -%}
+                {%- set _ = next.groups.append(replacement) -%}
+              {%- endif -%}
+            {%- elif group_labels == update.labels -%}
               {%- if update.host not in group.targets -%}
                 {%- set _ = group.targets.append(update.host) -%}
               {%- endif -%}
@@ -80,7 +105,7 @@
               {%- endif -%}
             {%- endif -%}
           {%- endfor -%}
-          {%- if not next.found -%}
+          {%- if update.state == 'present' and not next.found -%}
             {%- set new_group = {'targets': [update.host]} -%}
             {%- if update.labels | length > 0 -%}
               {%- set _ = new_group.update({'labels': update.labels}) -%}
@@ -89,7 +114,9 @@
           {%- endif -%}
           {%- set state.groups = next.groups -%}
         {%- endfor -%}
-        {%- set _ = output.files.append({'path': file._yaml_path, 'groups': state.groups}) -%}
+        {%- if file.content is defined or present_updates | length > 0 -%}
+          {%- set _ = output.files.append({'path': file._yaml_path, 'groups': state.groups}) -%}
+        {%- endif -%}
       {%- endfor -%}
       {{ output.files }}
   run_once: true