Add first cut at duct-tape for skaffold-debug

Author: briandealwis

skaffold-duct-tape/README.md

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+# Duct Tape
+
+_Caution: this is work-in-progress_
+
+This repository gathers additional dependencies required to debug
+particular language runtimes with `skaffold debug`.  These dependencies
+are packaged into an image container suitable for use as an
+`initContainer` on a pod.
+
+Currently supported:
+  * None!
+
+In Progress:
+
+  * Go: provides Delve
+
+## Development
+
+The idea is that `skaffold debug` will transform k8s manifests to
+make available any support files required to debug specific language
+runtimes.  For example, the `k8s-pod.yaml.orig` file shows an k8s
+podspec that would be transformed to `k8s-pod.yaml` to:
+  - mount a volume to hold the debugging support files
+  - provide an initContainer to populate the volume
+  - mount the volume to the applicable containers

skaffold-duct-tape/duct-tape/Dockerfile

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+FROM golang:1.11 as delve
+RUN curl --location --output delve-1.2.0.tar.gz https://github.com/go-delve/delve/archive/v1.2.0.tar.gz \
+ && tar xzf delve-1.2.0.tar.gz
+RUN cd delve-1.2.0/cmd/dlv && go install
+
+#
+#FROM python:2.7 as python27
+#RUN curl --location --output ptsvd.zip https://github.com/Microsoft/ptvsd/archive/v4.2.4.zip \
+# && unzip ptsvd.zip \
+# && cd ptsvd-4.2.4 \
+# && 
+
+# The debian image is about 95MB bigger
+FROM gcr.io/distroless/base:debug
+SHELL ["/busybox/sh","-c"]
+WORKDIR /duct-tape
+COPY --from=delve /go/bin/dlv .
+COPY install.sh /
+ENTRYPOINT ["/busybox/sh", "/install.sh"]

skaffold-duct-tape/duct-tape/install.sh

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+#!/bin/sh
+
+set -e
+echo "This is the duct-tape installation script!"
+
+if [ ! -d /dbg ]; then
+    echo "Debugging installation requires a volume mount at /dbg" 1>&2
+    exit 1
+fi
+
+# Install Delve for Go
+cp -p /duct-tape/dlv /dbg

skaffold-duct-tape/k8s-pod.yaml

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+apiVersion: v1
+kind: Pod
+metadata:
+  name: demo-duct-tape
+  labels:
+    app: demo-duct-tape
+spec:
+  initContainers:
+  - name: apply-duct-tape
+    image: gcr.io/gcp-dev-tools/duct-tape:latest
+    volumeMounts:
+    - name: dbg
+      mountPath: "/dbg"
+  containers:
+  - name: helloworld1
+    image: busybox
+    command: ['sh', '-c', 'echo "The app is running"; ls / /dbg; sleep 3600']
+    volumeMounts:
+    - name: dbg
+      mountPath: "/dbg"
+      readOnly: true
+  - name: helloworld2
+    image: busybox
+    command: ['sh', '-c', 'echo "The app is running"; ls / /dbg; sleep 3600']
+    volumeMounts:
+    - name: dbg
+      mountPath: "/dbg"
+      readOnly: true
+  volumes:
+  - name: dbg
+    emptyDir: {}

skaffold-duct-tape/k8s-pod.yaml.orig

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+apiVersion: v1
+kind: Pod
+metadata:
+  name: demo-duct-tape
+  labels:
+    app: demo-duct-tape
+spec:
+  containers:
+  - name: helloworld1
+    image: busybox
+    command: ['sh', '-c', 'echo "The app is running"; ls / /dbg; sleep 3600']
+  - name: helloworld2
+    image: busybox
+    command: ['sh', '-c', 'echo "The app is running"; ls / /dbg; sleep 3600']