serve up env.js based on environment for frontend applications

Author: leifj

src/pyff/constants.py

@@ -253,6 +253,7 @@ class Config(object):
     version = DummySetting('version', info="Show pyff version information", short='v', typeconv=as_bool)
     module = DummySetting("module", info="load additional plugins from the specified module", short='m')
     alias = DummySetting('alias', info="add an alias to the server - argument must be on the form alias=uri", short='A')
+    env = DummySetting('env', info='add an environment variable to the server', short='E')
 
     # deprecated settings
     google_api_key = S("google_api_key", deprecated=True)
@@ -313,6 +314,15 @@ class Config(object):
         info="a set of aliases to add to the server",
     )
 
+    environ = S(
+        "environ",
+        default=dict(),
+        typeconv=as_dict_of_string,
+        cmdline=['pyffd'],
+        hidden=True,
+        info="a set of environement variables to add to the server",
+    )
+
     base_dir = S("base_dir", info="change to this directory before executing the pipeline")
 
     modules = S("modules", default=[], typeconv=as_list_of_string, hidden=True, info="modules providing plugins")
@@ -513,6 +523,14 @@ def help(prg):
 config = Config()
 
 
+def opt_eq_split(s: str) -> str:
+    for sep in [':', '=']:
+        d = tuple(s.rsplit(sep))
+        if len(d) == 2:
+            return d
+    return (None, None)
+
+
 def parse_options(program, docs):
     (short_args, long_args) = config.args(program)
     docs += config.help(program)
@@ -529,6 +547,9 @@ def parse_options(program, docs):
     if config.aliases is None or len(config.aliases) == 0:
         config.aliases = dict(metadata=entities)
 
+    if config.environ is None or len(config.environ) == 0:
+        config.environ = dict()
+
     if config.modules is None:
         config.modules = []
 
@@ -545,6 +566,10 @@ def parse_options(program, docs):
                 assert colon == ':'
                 if a and uri:
                     config.aliases[a] = uri
+            elif o in ('-E', '--env'):
+                (k, v) = opt_eq_split(a)
+                if k and v:
+                    config.environ[k] = v
             elif o in ('-m', '--module'):
                 config.modules.append(a)
             else:

src/pyff/mdq.py

@@ -51,6 +51,7 @@ def main():
         'workers': config.worker_pool_size,
         'loglevel': config.loglevel,
         'preload_app': True,
+        'env': config.environ,
         'daemon': config.daemonize,
         'capture_output': False,
         'timeout': config.worker_timeout,

src/pyff/utils.py

@@ -28,7 +28,8 @@
 from threading import local
 from time import gmtime, strftime
 from typing import Any, BinaryIO, Callable, Dict, List, Optional, Sequence, Set, Tuple, Union
-
+from pyramid.request import Request as PyramidRequest
+from pyramid.response import Response as PyramidResponse
 import pkg_resources
 import requests
 import xmlsec
@@ -994,10 +995,13 @@ class FrontendApp(BaseModel):
     directory: str
     dirs: List[str] = []
     exts: Set[str] = set()
+    env: Dict[str, str] = dict()
 
     @staticmethod
-    def load(url_path: str, name: str, directory: str) -> FrontendApp:
-        fa = FrontendApp(url_path=url_path, name=name, directory=directory)
+    def load(url_path: str, name: str, directory: str, env: Optional[Mapping[str, str]] = None) -> FrontendApp:
+        if env is None:
+            env = config.environ
+        fa = FrontendApp(url_path=url_path, name=name, directory=directory, env=env)
         with os.scandir(fa.directory) as it:
             for entry in it:
                 if not entry.name.startswith('.'):
@@ -1008,8 +1012,17 @@ def load(url_path: str, name: str, directory: str) -> FrontendApp:
                         fa.exts.add(ext)
         return fa
 
+    def env_js_handler(self, request: PyramidRequest) -> PyramidResponse:
+        env_js = "window.env = {" + ",".join([f"{k}: '{v}'" for (k, v) in self.env.items()]) + "};"
+        response = PyramidResponse(env_js)
+        response.headers['Content-Type'] = 'text/javascript'
+        return response
+
     def add_route(self, ctx):
-        for uri_part in [self.url_path] + [self.url_path + d + "/" for d in self.dirs]:
+        env_route = '{}_env_js'.format(self.name)
+        ctx.add_route(env_route, '/env.js', request_method='GET')
+        ctx.add_view(self.env_js_handler, route_name=env_route)
+        for uri_part in [self.url_path] + [self.url_path + d for d in self.dirs]:
             route = '{}_{}'.format(self.name, uri_part)
             path = '{:s}{{sep:/?}}{{path:.*}}'.format(uri_part)
             ctx.add_route(