runner.docker: Set docker.image setting to the latest build-* tag by default

nextstrain/cli/command/check_setup.py

@@ -94,18 +94,20 @@ def run(opts: Options) -> int:
 
     # Print overall status.
     supported_runners = [
-        runner_name(runner)
+        runner
             for runner, status_ok in runner_status.items()
              if status_ok
     ]
 
     if supported_runners:
-        print("All good!  Supported Nextstrain environments:", ", ".join(map(success, supported_runners)))
+        print("All good!  Supported Nextstrain environments:", ", ".join(success(runner_name(r)) for r in supported_runners))
 
         if opts.set_default:
+            default_runner = supported_runners[0]
             print()
-            print("Setting default environment to %s." % supported_runners[0])
-            config.set("core", "runner", supported_runners[0])
+            print("Setting default environment to %s." % runner_name(default_runner))
+            config.set("core", "runner", runner_name(default_runner))
+            default_runner.set_default_config()
     else:
         print(failure("No good.  No support for any Nextstrain environment."))
 

nextstrain/cli/config.py

@@ -103,7 +103,25 @@ def set(section: str, field: str, value: str, path: Path = CONFIG):
         if section not in config:
             config.add_section(section)
 
-        config.set(section, field, value)
+        config[section][field] = value
+
+        save(config, path)
+
+
+def setdefault(section: str, field: str, value: str, path: Path = CONFIG):
+    """
+    Set *field* in *section* to *value* in the config file at the given *path*,
+    if *field* doesn't already exist.
+
+    If *section* does not exist, it is automatically created.
+    """
+    with write_lock():
+        config = load(path)
+
+        if section not in config:
+            config.add_section(section)
+
+        config[section].setdefault(field, value)
 
         save(config, path)
 

nextstrain/cli/runner/aws_batch/__init__.py

@@ -349,6 +349,13 @@ def test_setup() -> RunnerTestResults:
     ]
 
 
+def set_default_config() -> None:
+    """
+    No-op.
+    """
+    pass
+
+
 def update() -> bool:
     """
     No-op.  Updating the AWS Batch environment isn't meaningful.

nextstrain/cli/runner/docker.py

@@ -230,6 +230,14 @@ def test_image_version():
     ]
 
 
+def set_default_config() -> None:
+    """
+    Sets ``docker.image``, if it isn't already set, to the latest ``build-*``
+    image.
+    """
+    config.setdefault("docker", "image", latest_build_image(DEFAULT_IMAGE))
+
+
 def update() -> bool:
     """
     Pull down the latest Docker image build and prune old image versions.

nextstrain/cli/runner/native.py

@@ -41,6 +41,13 @@ def test_setup() -> RunnerTestResults:
     ]
 
 
+def set_default_config() -> None:
+    """
+    No-op.
+    """
+    pass
+
+
 def update() -> bool:
     """
     No-op.  Updating the native environment isn't reasonably possible.

nextstrain/cli/types.py

@@ -40,6 +40,9 @@ def run(opts: Options,
     @staticmethod
     def test_setup() -> Any: ...
 
+    @staticmethod
+    def set_default_config() -> None: ...
+
     @staticmethod
     def update() -> bool: ...