Merge branch 'hello-web' into 'master'

Hello web

Hello up there.

While studying how SlapOS works, I've turned helloworld example into real web-service.

New helloworld software-release was tested ok:

    - inside webrunner, and
    - instantiating in "raw" slapos locally under slapproxy.

Please apply and thanks beforehand,
Kirill

See merge request !2

software/helloworld/hello-web.in

+#!{{ python_executable }}
+"""Simple web-server that says "Hello World" for every path
+
+hello-web [--logfile <logfile>] <bind-ip> <bind-port> ...
+"""
+
+import sys
+import time
+import argparse
+from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
+from socket import AF_INET6
+
+
+class WebHello(BaseHTTPRequestHandler):
+
+    def do_GET(self):
+        self.send_response(200) # ok
+        self.send_header("Content-type", "text/plain")
+        self.end_headers()
+
+        print >>self.wfile, \
+            "Hello %s at `%s`  ; %s" % (
+                ' '.join(self.server.webhello_argv) or 'world',
+                self.path, time.asctime())
+
+
+class HTTPServerV6(HTTPServer):
+    address_family = AF_INET6
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--logfile', dest='logfile')
+    parser.add_argument('bind_ip')
+    parser.add_argument('bind_port', type=int)
+    parser.add_argument('argv_extra', metavar='...', nargs=argparse.REMAINDER)
+
+    args = parser.parse_args()
+
+    # HTTPServer logs to sys.stderr - override it if we have --logfile
+    if args.logfile:
+        f = open(args.logfile, 'a', buffering=1)
+        sys.stderr = f
+
+    print >>sys.stderr, '* %s Hello-Web starting at %s' % (
+        time.asctime(), (args.bind_ip, args.bind_port))
+
+    # TODO autodetect ipv6/ipv4
+    httpd = HTTPServerV6( (args.bind_ip, args.bind_port), WebHello)
+    httpd.webhello_argv = args.argv_extra
+    httpd.serve_forever()
+
+if __name__ == '__main__':
+    main()

software/helloworld/instance.cfg.in

@@ -7,6 +7,7 @@
 parts =
   directory
   hello-world
+  hello-world-promise
   publish-connection-parameter
 
 # Define egg directories to be the one from Software Release
@@ -58,23 +59,48 @@ promise = $${:etc}/promise/
 # Path of the log directory used by our service (see [hello-world])
 log = $${:var}/log
 
-# Create a simple shell script that will only output your name if you
-# specified it as instance parameter.
-# Usually, of course, we use more useful commands, like web servers.
+
+# Create a simple web server that says "hello <configuration.name>" to the web.
 [hello-world]
+# helloworld service is listening on:
+# - global IPv6 address, and
+# - fixed port
+#
+# NOTE because every computer partition is allocated its own global IPv6
+# address, it is ok to fix the port - different hello-world instances will have
+# different IPv6 addresses and they all will be accessible at the same time.
+ipv6 = $${instance-parameter:ipv6-random}
+port = 7777
+# full URL - for convenience
+url = http://[$${:ipv6}]:$${:port}
+
+# the service will log here
+logfile = $${directory:log}/hello-world.log
+
+# Actual script that starts the service:
 # This recipe will try to "exec" the command-line after separating parameters.
 recipe = slapos.cookbook:wrapper
-# Notice that there is only one $ at ${dash:location}, it is because it comes from the Software Release buildout profile.
-command-line = ${dash:location}/bin/dash -c 'echo "Hello $${instance-parameter:configuration.name}, it is $(date). If I were a server application, you would reach me at $${instance-parameter:global-ipv6}" > $${directory:log}/log.log; sleep 1000000;'
+command-line =
+    ${hello-web-bin:rendered} --logfile $${hello-world:logfile}
+        $${:ipv6} $${:port} $${instance-parameter:configuration.name}
 # Put this shell script in the "etc/service" directory. Each executable of this
 # repository will be started and monitored by supervisord. If a service
 # exits/crashes, it will trigger a "bang" and cause a re-run of the instance.
 wrapper-path = $${directory:service}/hello-world
 
 
+# promise, that checks that hello-world service is alive
+[hello-world-promise]
+recipe = slapos.cookbook:check_port_listening
+path = $${directory:promise}/hello-world
+hostname= $${hello-world:ipv6}
+port = $${hello-world:port}
+
+
 # Publish all the parameters needed for the user to connect to the instance.
 # It can be anything: URL(s), password(s), or arbitrary parameters.
 # Here we'll just echo back the entered name as instance parameter
 [publish-connection-parameter]
 recipe = slapos.cookbook:publish
 name = Hello $${instance-parameter:configuration.name}!
+url = $${hello-world:url}

software/helloworld/software.cfg

@@ -6,9 +6,10 @@ extends =
   ../../stack/slapos.cfg
 # Extend here component profiles, like openssl, apache, mariadb, curl...
 # Or/and extend a stack (lamp, tomcat) that does most of the work for you
-# In this example we only need the dash binary to run a simple "hello world"
-# shell script.
-  ../../component/dash/buildout.cfg
+# In this example we don't need anything more than python which is provided by
+# above stack/slapos.cfg
+# ../../component/component1/buildout.cfg
+# ../../component/component2/buildout.cfg
 
 parts =
 # Call installation of slapos.cookbook egg defined in stack/slapos.cfg (needed
@@ -18,6 +19,10 @@ parts =
 # instance
   instance-profile
 
+# "build" python program (install + correct shebang for our python)
+  hello-web-bin
+
+
 # Download instance.cfg.in (buildout profile used to deployment of instance),
 # replace all ${foo:bar} parameters by real values, and change $${foo:bar} to
 # ${foo:bar}
@@ -26,5 +31,23 @@ recipe = slapos.recipe.template
 url = ${:_profile_base_location_}/instance.cfg.in
 output = ${buildout:directory}/instance.cfg
 # MD5 checksum can be skipped for development (easier to develop), but must be filled for production
-md5sum = 1fea8a474f3b2eb7847685659441a3f9
+md5sum = 968bea0fc81dc604a874c53648b7d13f
 mode = 0644
+
+
+# install hello-web with correct python_executable
+[hello-web-bin]
+recipe = slapos.recipe.template:jinja2
+filename = hello-web
+md5sum = da4a93ff679d40c6682859476dcf4ce0
+template = ${:_profile_base_location_}/${:filename}.in
+rendered = ${buildout:bin-directory}/${:filename}
+mode = 0755
+# XXX python_executable should be ${${buildout:python}:executable}
+#     but buildout cannot support such indirection.
+#
+# in real-cases, python software is usually installed with zc.recipe.egg
+# which cares about correctly specifiing python interpreter for
+# entry-points automatically.
+context =
+    raw python_executable ${buildout:executable}