Extract publish heroku/now implementations into default plugins

This change introduces a new plugin hook, publish_subcommand, which can be
used to implement new subcommands for the "datasette publish" command family.

I've used this new hook to refactor out the "publish now" and "publish heroku"
implementations into separate modules. I've also added unit tests for these
two publishers, mocking the subprocess.call and subprocess.check_output
functions.

As part of this, I introduced a mechanism for loading default plugins. These
are defined in the new "default_plugins" list inside datasette/app.py

Closes #217 (Plugin support for datasette publish)
Closes #348 (Unit tests for "datasette publish")
Refs #14, #59, #102, #103, #146, #236, #347

datasette/app.py

@@ -2,6 +2,7 @@
 import click
 import collections
 import hashlib
+import importlib
 import itertools
 import os
 import sqlite3
@@ -41,6 +42,11 @@
 from .inspect import inspect_hash, inspect_views, inspect_tables
 from .version import __version__
 
+default_plugins = (
+    "datasette.publish.heroku",
+    "datasette.publish.now",
+)
+
 app_root = Path(__file__).parent.parent
 
 connections = threading.local()
@@ -49,6 +55,11 @@
 pm.add_hookspecs(hookspecs)
 pm.load_setuptools_entrypoints("datasette")
 
+# Load default plugins
+for plugin in default_plugins:
+    mod = importlib.import_module(plugin)
+    pm.register(mod, plugin)
+
 
 ConfigOption = collections.namedtuple(
     "ConfigOption", ("name", "default", "help")

datasette/cli.py

@@ -4,32 +4,17 @@
 import json
 import os
 import shutil
-from subprocess import call, check_output
+from subprocess import call
 import sys
-from .app import Datasette, DEFAULT_CONFIG, CONFIG_OPTIONS
+from .app import Datasette, DEFAULT_CONFIG, CONFIG_OPTIONS, pm
 from .utils import (
     temporary_docker_directory,
-    temporary_heroku_directory,
     value_as_boolean,
+    StaticMount,
     ValueAsBooleanError,
 )
 
 
-class StaticMount(click.ParamType):
-    name = "static mount"
-
-    def convert(self, value, param, ctx):
-        if ":" not in value:
-            self.fail(
-                '"{}" should be of format mountpoint:directory'.format(value),
-                param, ctx
-            )
-        path, dirpath = value.split(":")
-        if not os.path.exists(dirpath) or not os.path.isdir(dirpath):
-            self.fail("%s is not a valid directory path" % value, param, ctx)
-        return path, dirpath
-
-
 class Config(click.ParamType):
     name = "config"
 
@@ -93,202 +78,14 @@ def inspect(files, inspect_file, sqlite_extensions):
     open(inspect_file, "w").write(json.dumps(app.inspect(), indent=2))
 
 
-@cli.command()
-@click.argument("publisher", type=click.Choice(["now", "heroku"]))
-@click.argument("files", type=click.Path(exists=True), nargs=-1)
-@click.option(
-    "-n",
-    "--name",
-    default="datasette",
-    help="Application name to use when deploying",
-)
-@click.option(
-    "-m",
-    "--metadata",
-    type=click.File(mode="r"),
-    help="Path to JSON file containing metadata to publish",
-)
-@click.option("--extra-options", help="Extra options to pass to datasette serve")
-@click.option("--force", is_flag=True, help="Pass --force option to now")
-@click.option("--branch", help="Install datasette from a GitHub branch e.g. master")
-@click.option("--token", help="Auth token to use for deploy (Now only)")
-@click.option(
-    "--template-dir",
-    type=click.Path(exists=True, file_okay=False, dir_okay=True),
-    help="Path to directory containing custom templates",
-)
-@click.option(
-    "--plugins-dir",
-    type=click.Path(exists=True, file_okay=False, dir_okay=True),
-    help="Path to directory containing custom plugins",
-)
-@click.option(
-    "--static",
-    type=StaticMount(),
-    help="mountpoint:path-to-directory for serving static files",
-    multiple=True,
-)
-@click.option(
-    "--install",
-    help="Additional packages (e.g. plugins) to install",
-    multiple=True,
-)
-@click.option(
-    "--spatialite", is_flag=True, help="Enable SpatialLite extension"
-)
-@click.option("--version-note", help="Additional note to show on /-/versions")
-@click.option("--title", help="Title for metadata")
-@click.option("--license", help="License label for metadata")
-@click.option("--license_url", help="License URL for metadata")
-@click.option("--source", help="Source label for metadata")
-@click.option("--source_url", help="Source URL for metadata")
-def publish(
-    publisher,
-    files,
-    name,
-    metadata,
-    extra_options,
-    force,
-    branch,
-    token,
-    template_dir,
-    plugins_dir,
-    static,
-    install,
-    spatialite,
-    version_note,
-    **extra_metadata
-):
-    """
-    Publish specified SQLite database files to the internet along with a datasette API.
-
-    Options for PUBLISHER:
-        * 'now' - You must have Zeit Now installed: https://zeit.co/now
-        * 'heroku' - You must have Heroku installed: https://cli.heroku.com/
-
-    Example usage: datasette publish now my-database.db
-    """
-
-    def _fail_if_publish_binary_not_installed(binary, publish_target, install_link):
-        """Exit (with error message) if ``binary` isn't installed"""
-        if not shutil.which(binary):
-            click.secho(
-                "Publishing to {publish_target} requires {binary} to be installed and configured".format(
-                    publish_target=publish_target, binary=binary
-                ),
-                bg="red",
-                fg="white",
-                bold=True,
-                err=True,
-            )
-            click.echo(
-                "Follow the instructions at {install_link}".format(
-                    install_link=install_link
-                ),
-                err=True,
-            )
-            sys.exit(1)
-
-    if publisher == "now":
-        _fail_if_publish_binary_not_installed("now", "Zeit Now", "https://zeit.co/now")
-        if extra_options:
-            extra_options += " "
-        else:
-            extra_options = ""
-        extra_options += "--config force_https_urls:on"
-
-        with temporary_docker_directory(
-            files,
-            name,
-            metadata,
-            extra_options,
-            branch,
-            template_dir,
-            plugins_dir,
-            static,
-            install,
-            spatialite,
-            version_note,
-            extra_metadata,
-        ):
-            args = []
-            if force:
-                args.append("--force")
-            if token:
-                args.append("--token={}".format(token))
-            if args:
-                call(["now"] + args)
-            else:
-                call("now")
-
-    elif publisher == "heroku":
-        _fail_if_publish_binary_not_installed(
-            "heroku", "Heroku", "https://cli.heroku.com"
-        )
-        if spatialite:
-            click.secho(
-                "The --spatialite option is not yet supported for Heroku",
-                bg="red",
-                fg="white",
-                bold=True,
-                err=True,
-            )
-            click.echo(
-                "See https://github.com/simonw/datasette/issues/301",
-                err=True,
-            )
-            sys.exit(1)
-
-        # Check for heroku-builds plugin
-        plugins = [
-            line.split()[0] for line in check_output(["heroku", "plugins"]).splitlines()
-        ]
-        if b"heroku-builds" not in plugins:
-            click.echo(
-                "Publishing to Heroku requires the heroku-builds plugin to be installed."
-            )
-            click.confirm(
-                "Install it? (this will run `heroku plugins:install heroku-builds`)",
-                abort=True,
-            )
-            call(["heroku", "plugins:install", "heroku-builds"])
-
-        with temporary_heroku_directory(
-            files,
-            name,
-            metadata,
-            extra_options,
-            branch,
-            template_dir,
-            plugins_dir,
-            static,
-            install,
-            extra_metadata,
-        ):
-
-            app_name = None
-            if name:
-                # Check to see if this app already exists
-                list_output = check_output(["heroku", "apps:list", "--json"]).decode('utf8')
-                apps = json.loads(list_output)
+@cli.group()
+def publish():
+    "Publish specified SQLite database files to the internet along with a Datasette-powered interface and API"
+    pass
 
-                for app in apps:
-                    if app['name'] == name:
-                        app_name = name
-                        break
-
-            if not app_name:
-                # Create a new app
-                cmd = ["heroku", "apps:create"]
-                if name:
-                    cmd.append(name)
-                cmd.append("--json")
-                create_output = check_output(cmd).decode(
-                    "utf8"
-                )
-                app_name = json.loads(create_output)["name"]
 
-            call(["heroku", "builds:create", "-a", app_name])
+# Register publish plugins
+pm.hook.publish_subcommand(publish=publish)
 
 
 @cli.command()

datasette/hookspecs.py

@@ -23,3 +23,8 @@ def extra_css_urls():
 @hookspec
 def extra_js_urls():
     "Extra JavaScript URLs added by this plugin"
+
+
+@hookspec
+def publish_subcommand(publish):
+    "Subcommands for 'datasette publish'"

datasette/publish/__init__.py

@@ -0,0 +1 @@
+__all__ = ["heroku", "now"]

datasette/publish/common.py

@@ -0,0 +1,68 @@
+from ..utils import StaticMount
+import click
+import shutil
+import sys
+
+
+def add_common_publish_arguments_and_options(subcommand):
+    for decorator in reversed((
+        click.argument("files", type=click.Path(exists=True), nargs=-1),
+        click.option(
+            "-m",
+            "--metadata",
+            type=click.File(mode="r"),
+            help="Path to JSON file containing metadata to publish",
+        ),
+        click.option("--extra-options", help="Extra options to pass to datasette serve"),
+        click.option("--branch", help="Install datasette from a GitHub branch e.g. master"),
+        click.option(
+            "--template-dir",
+            type=click.Path(exists=True, file_okay=False, dir_okay=True),
+            help="Path to directory containing custom templates",
+        ),
+        click.option(
+            "--plugins-dir",
+            type=click.Path(exists=True, file_okay=False, dir_okay=True),
+            help="Path to directory containing custom plugins",
+        ),
+        click.option(
+            "--static",
+            type=StaticMount(),
+            help="mountpoint:path-to-directory for serving static files",
+            multiple=True,
+        ),
+        click.option(
+            "--install",
+            help="Additional packages (e.g. plugins) to install",
+            multiple=True,
+        ),
+        click.option("--version-note", help="Additional note to show on /-/versions"),
+        click.option("--title", help="Title for metadata"),
+        click.option("--license", help="License label for metadata"),
+        click.option("--license_url", help="License URL for metadata"),
+        click.option("--source", help="Source label for metadata"),
+        click.option("--source_url", help="Source URL for metadata"),
+    )):
+        subcommand = decorator(subcommand)
+    return subcommand
+
+
+def fail_if_publish_binary_not_installed(binary, publish_target, install_link):
+    """Exit (with error message) if ``binary` isn't installed"""
+    if not shutil.which(binary):
+        click.secho(
+            "Publishing to {publish_target} requires {binary} to be installed and configured".format(
+                publish_target=publish_target, binary=binary
+            ),
+            bg="red",
+            fg="white",
+            bold=True,
+            err=True,
+        )
+        click.echo(
+            "Follow the instructions at {install_link}".format(
+                install_link=install_link
+            ),
+            err=True,
+        )
+        sys.exit(1)