support Drone CI

README.md

@@ -7,6 +7,7 @@ Currently supported formats are
 [Bitbucket Pipelines](https://support.atlassian.com/bitbucket-cloud/docs/configure-bitbucket-pipelinesyml/),
 [GitLab CI](https://docs.gitlab.com/ee/ci/yaml/gitlab_ci_yaml.html),
 [GitHub Actions](https://docs.github.com/en/actions),
+[Drone CI](https://docs.drone.io/pipeline/overview/),
 and (very limited) [Ansible](https://docs.ansible.com/ansible/2.9/modules/shell_module.html)
 
 ## Usage
@@ -78,6 +79,12 @@ is considered a shell script.
 this is a todo, it should be simple enough to only check `sh` and `bash` scripts with right shebang line
 * [expressions](https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions) get replaced with a simple variable before running shellcheck
 
+### Drone CI
+
+Drone CI has a very simple file structure. As far as I can tell it only has
+conditions, but no deep nesting or includes. All command lists are concatenated
+and checked as a shell script.
+
 ### GitLab CI Pipelines
 
 GitLab CI files have more structure, and we try to support more of it.

test-input/.drone.yml

@@ -0,0 +1,18 @@
+---
+# Drone CI example, from https://docs.drone.io/pipeline/overview/
+kind: pipeline
+type: docker
+name: default
+
+steps:
+- name: backend
+  image: golang
+  commands:
+  - go build
+  - go test
+
+- name: frontend
+  image: node
+  commands:
+  - npm install
+  - npm run test

yaml_shellcheck.py

@@ -157,6 +157,23 @@ def get_runs(data, path):
     return result
 
 
+def get_drone_scripts(data):
+    """Drone CI has a simple file format, with all scripts in
+    `lists in steps[].commands[]`, see https://docs.drone.io/yaml/exec/
+    """
+    result = {}
+    if "steps" not in data:
+        return result
+    jobkey = data.get("name", "unknown")
+    for item in data["steps"]:
+        section = item.get("name")
+        result[f"{jobkey}/{section}"] = "\n".join(item.get("commands", []))
+    logging.debug("got scripts: %s", result)
+    for key in result:
+        logging.debug("%s: %s", key, result[key])
+    return result
+
+
 def get_gitlab_scripts(data):
     """GitLab is nice, as far as I can tell its files have a
     flat hierarchy with many small job entities"""
@@ -245,6 +262,11 @@ def select_yaml_schema(data, filename):
     elif isinstance(data, dict) and "on" in data and "jobs" in data:
         logging.info(f"read {filename} as GitHub Actions config...")
         return get_github_scripts
+    elif (
+        isinstance(data, dict) and "steps" in data and "kind" in data and "type" in data
+    ):
+        logging.info(f"read {filename} as Drone CI config...")
+        return get_drone_scripts
     elif isinstance(data, list):
         logging.info(f"read {filename} as Ansible file...")
         return get_ansible_scripts