From c821585b395fd5f453fc3109dceab077c60e70ca Mon Sep 17 00:00:00 2001
From: Radoslav Dimitrov <rdimitrow@gmail.com>
Date: Sun, 2 Sep 2018 23:44:06 +0300
Subject: [PATCH] Sample-functions: Get watchdog using curl instead of ADD -
 Docs

Convert all sample-functions to use curl to get the watchdog as
it can be cached by Docker. Issue #841

Signed-off-by: Radoslav Dimitrov <rdimitrow@gmail.com>
---
 DEV.md             | 22 +++++++++++++++++++---
 watchdog/README.md | 11 ++++++++++-
 2 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/DEV.md b/DEV.md
index 045a532b..e4c96ebe 100644
--- a/DEV.md
+++ b/DEV.md
@@ -35,7 +35,7 @@ RUN go get github.com/microcosm-cc/bluemonday && \
 
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .
 
-ADD https://github.com/openfaas/faas/releases/download/0.8.0/fwatchdog /usr/bin
+ADD https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog /usr/bin
 RUN chmod +x /usr/bin/fwatchdog
 
 ENV fprocess="/go/src/app/app"
@@ -61,7 +61,7 @@ Update the Docker stack with this:
 ```
 FROM alpine:latest
 
-ADD https://github.com/openfaas/faas/releases/download/0.8.0/fwatchdog /usr/bin
+ADD https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog /usr/bin
 RUN chmod +x /usr/bin/fwatchdog
 
 ENV fprocess="wc"
@@ -78,7 +78,23 @@ Update your Docker stack with this definition:
         networks:
             - functions
         environment:
-            fprocess:	"wc"
+            fprocess: "wc"
+```
+
+**Tip:**
+You can optimize Docker to cache getting the watchdog by using curl, instead of ADD.
+To do so, replace the related lines with:
+```
+RUN apt-get update && apt-get install -y curl \
+    && curl -sL https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog \
+    && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+```
+or with the following for Alpine based images:
+```
+RUN apk --no-cache add curl \
+    && curl -sL https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog
 ```
 
 ### Testing your function
diff --git a/watchdog/README.md b/watchdog/README.md
index 7c794a6e..687e342f 100644
--- a/watchdog/README.md
+++ b/watchdog/README.md
@@ -36,7 +36,7 @@ Example Dockerfile for an `echo` function:
 ```
 FROM alpine:3.7
 
-ADD https://github.com/openfaas/faas/releases/download/0.8.0/fwatchdog /usr/bin
+ADD https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog /usr/bin
 RUN chmod +x /usr/bin/fwatchdog
 
 # Define your binary here
@@ -45,6 +45,15 @@ ENV fprocess="/bin/cat"
 CMD ["fwatchdog"]
 ```
 
+**Tip:**
+You can optimize Docker to cache getting the watchdog by using curl, instead of ADD.
+To do so, replace the related lines with:
+```
+RUN apk --no-cache add curl \
+    && curl -sL https://github.com/openfaas/faas/releases/download/0.9.0/fwatchdog > /usr/bin/fwatchdog \
+    && chmod +x /usr/bin/fwatchdog
+```
+
 **Implementing a health-check**
 
 At any point in time, if you detect that your function has become unhealthy and needs to restart, then you can delete the `/tmp/.lock` file which invalidates the check and causes Swarm to re-schedule the function.