use environment variables (#740)

* use environment variables

.travis.yml

@@ -51,7 +51,8 @@ before_install:
   -     ./flow/scripts/setup_aimsun.sh
   - popd
   - source ~/.bashrc
-  - sed -i 's/\/path\/to\/envs\/aimsun_flow/\/home\/travis\/miniconda\/envs\/aimsun_flow/g' flow/config.py
+  - export AIMSUN_SITEPACKAGES="/home/travis/miniconda/envs/aimsun_flow"
+  - export AIMSUN_NEXT_PATH="/home/user/Aimsun_Next_XXX"
 
   - ls ../
 

docs/source/flow_setup.rst

@@ -141,14 +141,14 @@ can be achieved by following the installation instructions located in:
 https://www.aimsun.com/aimsun-next/download/.
 
 Once Aimsun has been installed, copy the path to the `Aimsun_Next` main
-directory and place it in under the `AIMSUN_NEXT_PATH` variable in the
-"flow/config.py" folder. This will allow Flow to locate and use this binary
+directory and place it in under the `AIMSUN_NEXT_PATH` variable in your bashrc.
+This will allow Flow to locate and use this binary
 during the execution of various tasks. The path should look something like:
 
 ::
 
-    /home/user/Aimsun_Next_X_Y_Z/                   # Linux
-    /Applications/Aimsun Next.app/Contents/MacOS/   # OS X
+    export AIMSUN_NEXT_PATH="/home/user/Aimsun_Next_X_Y_Z/"                   # Linux
+    export AIMSUN_NEXT_PATH="/Applications/Aimsun Next.app/Contents/MacOS/"   # OS X
 
 `Note for Mac users:` when you download Aimsun, you will get a folder named "Programming". You need to rename it to "programming" (all lowercase) and to move it inside the "Aimsun Next.app/Contents/MacOS/" directory so that the python API can work.
 
@@ -178,8 +178,11 @@ The latter command should return an output similar to:
     /path/to/envs/aimsun_flow/bin/python
 
 Copy the path up until right before /bin (i.e. /path/to/envs/aimsun_flow) and
-place it under the `AIMSUN_SITEPACKAGES` variable in flow/config.py.
+place it under the `AIMSUN_SITEPACKAGES` variable in your bashrc, like this:
 
+::
+
+    export AIMSUN_SITEPACKAGES="/path/to/envs/aimsun_flow/bin/python"
 
 Testing your installation
 ~~~~~~~~~~~~~~~~~~~~~~~~~

flow/config.py

@@ -19,8 +19,8 @@
 AWS_S3_PATH = "s3://bucket_name"
 
 # path to the Aimsun_Next main directory (required for Aimsun simulations)
-AIMSUN_NEXT_PATH = "/home/user/Aimsun_Next_XXX"
+AIMSUN_NEXT_PATH = os.environ.get("AIMSUN_NEXT_PATH", None)
 
 # path to the aimsun_flow environment's main directory (required for Aimsun
 # simulations)
-AIMSUN_SITEPACKAGES = "/path/to/envs/aimsun_flow"
+AIMSUN_SITEPACKAGES = os.environ.get("AIMSUN_SITEPACKAGES", None)

flow/utils/aimsun/scripting_api.py

@@ -4,12 +4,18 @@
 
 import flow.config as config
 
-SITEPACKAGES = os.path.join(config.AIMSUN_SITEPACKAGES,
-                            "lib/python2.7/site-packages")
-sys.path.append(SITEPACKAGES)
-
-sys.path.append(os.path.join(config.AIMSUN_NEXT_PATH,
-                             'programming/Aimsun Next API/AAPIPython/Micro'))
+try:
+    SITEPACKAGES = os.path.join(config.AIMSUN_SITEPACKAGES,
+                                "lib/python2.7/site-packages")
+    sys.path.append(SITEPACKAGES)
+except TypeError:
+    raise EnvironmentError("Please declare the AIMSUN_SITEPACKAGES environment variable.")
+
+try:
+    sys.path.append(os.path.join(config.AIMSUN_NEXT_PATH,
+                                 'programming/Aimsun Next API/AAPIPython/Micro'))
+except TypeError:
+    raise EnvironmentError("Please declare the AIMSUN_NEXT_PATH environment variable.")
 
 
 class AimsunTemplate(object):