Add schema validation error message

This change updates the json_to_dhall task to provides a better
failure message.

This change also refactors the CR spec transformation
using jinja combinaison filter to be able to use the raw spec directly.

Finally this change removes a copy of the spec from the local playbook
by using the flat cr_spec file directly.

Change-Id: I6ed5c6746f01a8a277d50bdef317e56dfde5f66d

playbooks/files/local.yaml

@@ -9,23 +9,7 @@
     meta:
       name: zuul
       namespace: default
-    spec:
-      executor:
-        count: 1
-        ssh_key:
-          secretName: executor-ssh-key
-      merger:
-        count: 1
-      scheduler:
-        config:
-          secretName: zuul-yaml-conf
-      launcher:
-        config:
-          secretName: nodepool-yaml-conf
-      connections:
-        gits:
-          - baseurl: https://opendev.org
-            name: opendev.org
+    spec: "{{ lookup('file', './cr_spec.yaml') | from_yaml }}"
   pre_tasks:
     - name: "Create necessary secrets"
       k8s:

roles/zuul/defaults/main.yaml

@@ -6,3 +6,8 @@ zuul_app_path: "/opt/ansible/conf/zuul"
 # Here we use zuul_spec to get un-modified cr
 # see: https://github.com/operator-framework/operator-sdk/issues/1770
 raw_spec: "{{ vars['_operator_zuul-ci_org_zuul_spec'] | default(spec) }}"
+
+# Provide sensible default for non optional attributes:
+spec_defaults:
+  web: {}
+  externalConfig: {}

roles/zuul/library/json_to_dhall.py

@@ -24,7 +24,7 @@ def pread(args: List[str], stdin: str) -> str:
     proc = subprocess.Popen(args, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
     stdout, stderr = proc.communicate(stdin.encode('utf-8'))
     if stderr:
-        raise RuntimeError("Command failed: " + stderr.decode('utf-8'))
+        raise RuntimeError(stderr.decode('utf-8'))
     return stdout.decode('utf-8')
 
 
@@ -43,7 +43,7 @@ def ansible_main():
     try:
         module.exit_json(changed=True, result=run(p['schema'], p['json']))
     except Exception as e:
-        module.fail_json(msg="Dhall expression failed:" + str(e))
+        module.fail_json(msg="Dhall expression failed", error=str(e))
 
 
 def cli_main():

roles/zuul/tasks/main.yaml

@@ -9,18 +9,21 @@
     schema: "({{ zuul_app_path }}/input.dhall).Input.Type"
     json: "{{ rspec | to_json }}"
   vars:
-    rspec:
-      name: "{{ zuul_name }}"
-      merger: "{{ raw_spec['merger'] | default({}) }}"
-      executor: "{{ raw_spec['executor'] | default({}) }}"
-      web: "{{ raw_spec['web'] | default({}) }}"
-      scheduler: "{{ raw_spec['scheduler'] | default({}) }}"
-      launcher: "{{ raw_spec['launcher'] | default({}) }}"
-      jobVolumes: "{{ raw_spec['jobVolumes'] | default([]) }}"
-      externalConfig: "{{ raw_spec['externalConfig'] | default({}) }}"
-      connections: "{{ raw_spec['connections'] | default({}) }}"
+    rspec: "{{ spec_defaults | combine(raw_spec) | combine({'name': zuul_name}) }}"
+  failed_when: false
   register: _cr_input
 
+- name: Explain schema conversion issue
+  when: _cr_input.error is defined
+  fail:
+    msg: |
+      The provided Zuul spec is incorrect:
+
+      {{ _cr_input.error }}
+
+      Attributes starting with a `-` are expected.
+      Attributes starting with a `+` were provided but not expected.
+
 - name: Convert expression to kubernetes objects
   dhall_to_json:
     expression: "{{ zuul_app_path }}/resources.dhall {{ _cr_input.result }}"