Add syntax checker for Ansible

CHANGES.rst

@@ -3,6 +3,7 @@
 
 - New features and improvements
 
+ - New checker for Ansible YAML using ``ansible-lint``.
  - The ``flycheck-verify-setup`` UI now includes buttons to re-enable manually
  disabled checkers and to try to re-enable automatically disabled checkers
  (command checkers are automatically disabled when their executable cannot be

doc/languages.rst

@@ -48,6 +48,14 @@ to view the docstring of the syntax checker. Likewise, you may use
  A list of additional warnings to enable. Each item is the name of a
  warning category to enable.
 
+.. supported-language:: Ansible
+
+ .. syntax-checker:: ansible-ansiblelint
+
+ Check Ansible YAML files with ansible-lint_.
+
+ .. _ansible-lint: https://ansible-lint.readthedocs.io
+
 .. supported-language:: AsciiDoc
 
  .. syntax-checker:: asciidoctor

flycheck.el

@@ -168,6 +168,7 @@ attention to case differences."
 
 (defcustom flycheck-checkers
  '(ada-gnat
+ ansible-ansiblelint
  asciidoctor
  asciidoc
  awk-gawk
@@ -7464,6 +7465,43 @@ Uses the GNAT compiler from GCC. See URL
  ": " (message) line-end))
  :modes ada-mode)
 
+(flycheck-define-checker ansible-ansiblelint
+ "An Ansible linter using the ansible-lint tool.
+
+See URL `https://ansible-lint.readthedocs.io/en/latest/'."
+ ;; emacs-ansible provides ansible, not ansible-mode
+ :enabled (bound-and-true-p ansible)
+ :command ("ansible-lint" "--nocolor" "-p" source)
+ :error-patterns
+ ((error "CRITICAL Couldn't parse task at " (file-name) ":" line " " (message))
+ (warning line-start (file-name) ":" line ": [E" (id (+ digit)) "] " (message)
+ line-end))
+ :error-explainer
+ (lambda (err)
+ (let* ((id (flycheck-error-id err))
+ (lines (process-lines "ansible-lint" "-L" "-f" "plain"))
+ ;; process-lines may flush output before the entire line of the rule
+ ;; is ready; reconstruct the desired error to a single line
+ (start (+ 1 (seq-position
+ lines t
+ (lambda (elt _)
+ (string-prefix-p id elt)))))
+ (next-id (car (seq-filter
+ (lambda (elt)
+ (string-match-p "^[0-9]\\{3,4\\}: " elt))
+ (nthcdr start lines))))
+ (end (if (not next-id)
+ (length lines)
+ (seq-position
+ lines t
+ (lambda (elt _)
+ (string-prefix-p next-id elt))))))
+ (substring (mapconcat 'identity (seq-subseq lines start end) "") 2)))
+ :modes yaml-mode
+ :next-checkers ((t . yaml-jsyaml)
+ (t . yaml-ruby)
+ (t . yaml-yamllint)))
+
 (flycheck-define-checker asciidoc
  "A AsciiDoc syntax checker using the AsciiDoc compiler.
 

test/flycheck-test.el

@@ -3102,6 +3102,22 @@ evaluating BODY."
  '( 6 4 warning "variable \"Name\" is not referenced" :checker ada-gnat)
  '(8 11 warning "unrecognized pragma \"Foo\"" :checker ada-gnat)))
 
+(flycheck-ert-def-checker-test ansible-ansiblelint ansible errors
+ (flycheck-ert-should-syntax-check
+ "language/ansible/error.yml" 'yaml-mode
+ '(3 nil error "(conflicting action statements: debug, command)"
+ :checker ansible-ansiblelint)))
+
+(flycheck-ert-def-checker-test ansible-ansiblelint ansible warnings
+ (flycheck-ert-should-syntax-check
+ "language/ansible/warnings.yml" 'yaml-mode
+ '(5 nil warning "Commands should not change things if nothing needs doing"
+ :checker ansible-ansiblelint)
+ '(5 nil warning "service used in place of service module"
+ :checker ansible-ansiblelint)
+ '(9 nil warning "variables should have spaces before and after: {{ varname }}"
+ :checker ansible-ansiblelint)))
+
 (flycheck-ert-def-checker-test asciidoc asciidoc nil
  (let ((flycheck-disabled-checkers '(asciidoctor)))
  (flycheck-ert-should-syntax-check

test/resources/language/ansible/error.yml

@@ -0,0 +1,11 @@
+- hosts: localhost
+ tasks:
+ - name: foo
+ debug:
+ msg: bar
+ command: echo
+# On this file ansible-playbook --syntax-check reports:
+# ERROR! conflicting action statements: debug, command
+#
+# The error appears to be in 'test/conflicting_action.yml': line 3, column 7, but may
+# be elsewhere in the file depending on the exact syntax problem.

test/resources/language/ansible/warnings.yml

@@ -0,0 +1,9 @@
+---
+- hosts: bobbins
+
+ tasks:
+ - name: a bad play
+ action: command service blah restart
+
+ - name: incorrect brackets
+ file: "{{space}}"