Fix hashi_vault lookup approle authentication (#1138)

As per the plugin documentation and the Hashicorp Vault documentation (https://www.vaultproject.io/docs/auth/approle#secretid)
secret_id is not mandatory.
Moreover, using this lookup plugin without a secret_id used to work in
Ansible 2.9.

Co-authored-by: Jonathan Piron <jonathanpiron@gmail.com>

changelogs/fragments/1138-hashi_vault_fix_approle_authentication_without_secret_id.yml

@@ -0,0 +1,2 @@
+bugfixes:
+- hashi_vault - fix approle authentication without ``secret_id`` (https://github.com/ansible-collections/community.general/pull/1138).

plugins/lookup/hashi_vault.py

@@ -588,7 +588,7 @@ class LookupModule(LookupBase):
         self.validate_by_required_fields(auth_method, 'username', 'password')
 
     def validate_auth_approle(self, auth_method):
-        self.validate_by_required_fields(auth_method, 'role_id', 'secret_id')
+        self.validate_by_required_fields(auth_method, 'role_id')
 
     def validate_auth_token(self, auth_method):
         if auth_method == 'token':

tests/integration/targets/lookup_hashi_vault/lookup_hashi_vault/tasks/approle_secret_id_less_setup.yml

@@ -0,0 +1,19 @@
+- name: 'Create an approle policy'
+  shell: "echo '{{ policy }}' | {{ vault_cmd }} policy write approle-policy-2 -"
+  vars:
+    policy: |
+      path "auth/approle/login" {
+       capabilities = [ "create", "read" ]
+      }
+
+- name: 'Enable the AppRole auth method'
+  command: '{{ vault_cmd }} auth enable approle'
+  register: enable_approle
+  failed_when: "enable_approle.rc!=0 and 'path is already in use' not in enable_approle.stderr"
+
+- name: 'Create a named role without secret id'
+  command: '{{ vault_cmd }} write auth/approle/role/test-role-2 policies="test-policy,approle-policy-2" bind_secret_id=false secret_id_bound_cidrs="0.0.0.0/0"'
+
+- name: 'Fetch the RoleID of the AppRole'
+  command: '{{ vault_cmd }} read -field=role_id auth/approle/role/test-role-2/role-id'
+  register: role_id_cmd_2

tests/integration/targets/lookup_hashi_vault/lookup_hashi_vault/tasks/approle_secret_id_less_test.yml

@@ -0,0 +1,44 @@
+- vars:
+    role_id: '{{ role_id_cmd_2.stdout }}'
+  block:
+    - name: 'Fetch secrets using "hashi_vault" lookup'
+      set_fact:
+        secret1: "{{ lookup('community.general.hashi_vault', conn_params ~ 'secret=' ~ vault_kv2_path ~ '/secret1 auth_method=approle role_id=' ~ role_id) }}"
+        secret2: "{{ lookup('community.general.hashi_vault', conn_params ~ 'secret=' ~ vault_kv2_path ~ '/secret2 auth_method=approle role_id=' ~ role_id) }}"
+
+    - name: 'Check secret values'
+      fail:
+        msg: 'unexpected secret values'
+      when: secret1['value'] != 'foo1' or secret2['value'] != 'foo2'
+
+    - name: 'Failure expected when erroneous credentials are used'
+      vars:
+        secret_wrong_cred: "{{ lookup('community.general.hashi_vault', conn_params ~ 'secret=' ~ vault_kv2_path ~ '/secret2 auth_method=approle role_id=foobar') }}"
+      debug:
+        msg: 'Failure is expected ({{ secret_wrong_cred }})'
+      register: test_wrong_cred
+      ignore_errors: true
+
+    - name: 'Failure expected when unauthorized secret is read'
+      vars:
+        secret_unauthorized: "{{ lookup('community.general.hashi_vault', conn_params ~ 'secret=' ~ vault_kv2_path ~ '/secret3 auth_method=approle role_id=' ~ role_id) }}"
+      debug:
+        msg: 'Failure is expected ({{ secret_unauthorized }})'
+      register: test_unauthorized
+      ignore_errors: true
+
+    - name: 'Failure expected when inexistent secret is read'
+      vars:
+          secret_inexistent: "{{ lookup('community.general.hashi_vault', conn_params ~ 'secret=' ~ vault_kv2_path ~ '/non_existent_secret4 auth_method=approle role_id=' ~ role_id) }}"
+      debug:
+        msg: 'Failure is expected ({{ secret_inexistent }})'
+      register: test_inexistent
+      ignore_errors: true
+
+    - name: 'Check expected failures'
+      assert:
+        msg: "an expected failure didn't occur"
+        that:
+          - test_wrong_cred is failed
+          - test_unauthorized is failed
+          - test_inexistent is failed

tests/integration/targets/lookup_hashi_vault/lookup_hashi_vault/tasks/main.yml

@@ -146,6 +146,10 @@
               import_tasks: approle_setup.yml
               when: ansible_distribution != 'RedHat' or ansible_distribution_major_version is version('7', '>')
 
+            - name: setup approle secret_id_less auth
+              import_tasks: approle_secret_id_less_setup.yml
+              when: ansible_distribution != 'RedHat' or ansible_distribution_major_version is version('7', '>')
+
             - name: setup token auth
               import_tasks: token_setup.yml
 
@@ -158,6 +162,11 @@
             auth_type: approle
           when: ansible_distribution != 'RedHat' or ansible_distribution_major_version is version('7', '>')
 
+        - import_tasks: tests.yml
+          vars:
+            auth_type: approle_secret_id_less
+          when: ansible_distribution != 'RedHat' or ansible_distribution_major_version is version('7', '>')
+
         - import_tasks: tests.yml
           vars:
             auth_type: token