From 6f6a0dcbab50d24414a1a4060a9e6af9801c6185 Mon Sep 17 00:00:00 2001
From: "Ivana Yovcheva (VMware)" <iyovcheva@vmware.com>
Date: Tue, 10 Jul 2018 19:20:34 +0300
Subject: [PATCH] Add build options examples

This adds an example of how to practically use `build-option`
with pillow for Python

Signed-off-by: Ivana Yovcheva (VMware) <iyovcheva@vmware.com>
---
 docs/cli/build.md | 62 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/docs/cli/build.md b/docs/cli/build.md
index d6c7838a..9c1fb108 100644
--- a/docs/cli/build.md
+++ b/docs/cli/build.md
@@ -70,6 +70,7 @@ ARG ADDITIONAL_PACKAGE
 RUN apk --no-cache add curl ${ADDITIONAL_PACKAGE} \  
 
 ```
+<<<<<<< HEAD
 ## 2.0 Pass ADDITIONAL_PACKAGE through `--build-arg`
 
 There may be scenarios where a single native module need to be added to a build.  A single-package build option could be added as described above.  Alternatively a package could be specified through a `--build-arg`.
@@ -101,4 +102,63 @@ Remeber to add any `ARG` values to the template's Dockerfile:
  ARG ARGNAME2
  ```
 
- For more information about passing build arguments to Docker, please visit the [Docker documentation](https://docs.docker.com/engine/reference/commandline/build/)
\ No newline at end of file
+ For more information about passing build arguments to Docker, please visit the [Docker documentation](https://docs.docker.com/engine/reference/commandline/build/)
+=======
+
+## 2.1 Build options examples
+
+Let's see some practical examples with the `build-option` flag.
+
+* Use [Pillow](https://pillow.readthedocs.io/en/5.2.x/) for image processing in your Python function
+
+Create function with
+
+```
+$ faas-cli new faas_black_and_white --lang python3 --prefix <your-docker-namespace>
+```
+
+Add `pillow` to `requirements.txt` .
+
+Copy some resource images to `faas_black_and_white/`.
+
+Edit `handler.py`:
+
+```python
+import os
+from PIL import Image
+
+def handle(req):
+    img = Image.open("function/" + req)
+
+    blackAndWhite = img.convert('1')
+
+    blackAndWhite.save("function/blackAndWhite.jpeg")
+
+    with open("function/blackAndWhite.jpeg", 'rb') as pic:
+        res = pic.read()
+
+    os.write(1, res)
+    return res
+```
+
+What the code does is to open an image, available in resources and convert it to black and white.
+
+Now build the function with build options:
+```
+faas build -f faas_black_and_white.yml --build-option dev --build-option pillow
+```
+
+Push and deploy:
+```
+faas push -f faas_black_and_white.yml && faas deploy -f faas_black_and_white.yml
+```
+
+Test the function with:
+
+```bash
+echo "image-name.jpg" | faas invoke pillow-func > blackAndWhite.jpg
+```
+
+Or in your web browser by opening http://127.0.0.1:8080/function/pillow-func
+
+>>>>>>> Add build options examples