Initial Commit

.editorconfig

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+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = false
+
+[Makefile]
+indent_style = tab

.gitignore

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+getidev

.golangci.yml

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+run:
+  skip-dirs:
+  - it
+  timeout: 10m
+  tests: true
+
+linters:
+  disable-all: true
+  enable:
+  # Default
+  - deadcode
+  - errcheck
+  - gosimple
+  - govet
+  - ineffassign
+  - staticcheck
+  - structcheck
+  - typecheck
+  - unused
+  - varcheck
+
+  # Additionally linters
+  - bodyclose
+  - misspell
+  - nilerr
+  - rowserrcheck
+  - sqlclosecheck
+  - unparam
+  - whitespace

Dockerfile

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+ARG BASE_IMAGE
+ARG BUILD_IMAGE
+
+# BUILD
+# =====================================================================
+FROM ${BUILD_IMAGE} AS build
+
+ARG GONOPROXY
+ARG GONOSUMDB
+ARG GOPRIVATE
+ARG GOPROXY
+ARG GOSUMDB
+ARG VERSION
+
+COPY ./ /workspace
+
+RUN cd /workspace && \
+    GONOPROXY=${GONOPROXY} \
+    GONOSUMDB=${GONOSUMDB} \
+    GOPRIVATE=${GOPRIVATE} \
+    GOPROXY=${GOPROXY} \
+    GOSUMDB=${GOSUMDB} \
+    VERSION=${VERSION} \
+      make all
+
+# TARGET
+# =====================================================================
+FROM ${BASE_IMAGE}
+
+COPY --from=build /workspace/getidev /usr/bin/getidev
+
+ENTRYPOINT [ "/usr/bin/getidev" ]

LICENSE

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+Copyright 2019 Markus Pesch
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

Makefile

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+# VERSION
+VERSION?=$(shell git describe --abbrev=0)+hash.$(shell git rev-parse --short HEAD)
+
+# CONTAINER_RUNTIME
+CONTAINER_RUNTIME?=$(shell which docker)
+
+# BUILD_IMAGE
+BUILD_IMAGE_REGISTRY_HOST?=docker.io
+BUILD_IMAGE_NAMESPACE=library
+BUILD_IMAGE_REPOSITORY=golang
+BUILD_IMAGE_VERSION?=1.16
+BUILD_IMAGE_FULLY_QUALIFIED:=${BUILD_IMAGE_REGISTRY_HOST}/${BUILD_IMAGE_NAMESPACE}/${BUILD_IMAGE_REPOSITORY}:${BUILD_IMAGE_VERSION}
+
+# BASE_IMAGE
+BASE_IMAGE_REGISTRY_HOST?=docker.io
+BASE_IMAGE_NAMESPACE=library
+BASE_IMAGE_REPOSITORY=busybox
+BASE_IMAGE_VERSION?=latest
+BASE_IMAGE_FULLY_QUALIFIED=${BASE_IMAGE_REGISTRY_HOST}/${BASE_IMAGE_NAMESPACE}/${BASE_IMAGE_REPOSITORY}:${BASE_IMAGE_VERSION}
+
+# CONTAINER_IMAGE
+CONTAINER_IMAGE_REGISTRY_HOST?=docker.io
+CONTAINER_IMAGE_NAMESPACE=volkerraschek
+CONTAINER_IMAGE_REPOSITORY=getidev
+CONTAINER_IMAGE_VERSION?=latest
+CONTAINER_IMAGE_FULLY_QUALIFIED=${CONTAINER_IMAGE_REGISTRY_HOST}/${CONTAINER_IMAGE_NAMESPACE}/${CONTAINER_IMAGE_REPOSITORY}:${CONTAINER_IMAGE_VERSION}
+CONTAINER_IMAGE_UNQUALIFIED=${CONTAINER_IMAGE_NAMESPACE}/${CONTAINER_IMAGE_REPOSITORY}:${CONTAINER_IMAGE_VERSION}
+
+# EXECUTABLES
+# ==============================================================================
+EXECUTABLE_TARGETS=getidev
+
+PHONY=all
+all: clean ${EXECUTABLE_TARGETS}
+
+getidev:
+	GOPRIVATE=$(shell go env GOPRIVATE) \
+	GOPROXY=$(shell go env GOPROXY) \
+	GONOPROXY=$(shell go env GONOPROXY) \
+	GONOSUMDB=$(shell go env GONOSUMDB) \
+	GOSUMDB=$(shell go env GOSUMDB) \
+		go build -tags netgo -ldflags "-X main.version=${VERSION}" -o ${@} main.go
+
+# CLEAN
+# ==============================================================================
+PHONY+=clean
+clean:
+	rm --force --recursive $(shell pwd)/getidev*
+
+# GOLANGCI-LINT
+# ==============================================================================
+PHONY+=golangci-lint
+golangci-lint:
+	golangci-lint run --concurrency=$(shell nproc)
+
+# GOSEC
+# ==============================================================================
+PHONY+=gosec
+gosec:
+	gosec $(shell pwd)/...
+
+# CONTAINER-IMAGE
+# ==============================================================================
+PHONY+=container-image/build
+container-image/build:
+	${CONTAINER_RUNTIME} build \
+		--build-arg BASE_IMAGE=${BASE_IMAGE_FULLY_QUALIFIED} \
+		--build-arg BUILD_IMAGE=${BUILD_IMAGE_FULLY_QUALIFIED} \
+		--build-arg GOPRIVATE=$(shell go env GOPRIVATE) \
+		--build-arg GOPROXY=$(shell go env GOPROXY) \
+		--build-arg GONOPROXY=$(shell go env GONOPROXY) \
+		--build-arg GONOSUMDB=$(shell go env GONOSUMDB) \
+		--build-arg GOSUMDB=$(shell go env GOSUMDB) \
+		--build-arg VERSION=${VERSION} \
+		--file ./Dockerfile \
+		--no-cache \
+		--tag ${CONTAINER_IMAGE_UNQUALIFIED} \
+		--tag ${CONTAINER_IMAGE_FULLY_QUALIFIED} \
+		.
+
+PHONY+=container-image/push
+container-image/push: container-image/build
+	${CONTAINER_RUNTIME} push ${CONTAINER_IMAGE_FULLY_QUALIFIED}
+
+# CONTAINER STEPS - EXECUTABLE
+# ==============================================================================
+PHONY+=container-run/all
+container-run/all:
+	$(MAKE) container-run COMMAND=${@:container-run/%=%}
+
+PHONY+=${EXECUTABLE_TARGETS:%=container-run/%}
+${EXECUTABLE_TARGETS:%=container-run/%}:
+	$(MAKE) container-run COMMAND=${@:container-run/%=%}
+
+# CONTAINER STEPS - CLEAN
+# ==============================================================================
+PHONY+=container-run/clean
+container-run/clean:
+	$(MAKE) container-run COMMAND=${@:container-run/%=%}
+
+# GENERAL CONTAINER COMMAND
+# ==============================================================================
+PHONY+=container-run
+container-run:
+	${CONTAINER_RUNTIME} run \
+		--env CONTAINER_IMAGE_VERSION=${CONTAINER_IMAGE_VERSION} \
+		--env GONOPROXY=$(shell go env GONOPROXY) \
+		--env GONOSUMDB=$(shell go env GONOSUMDB) \
+		--env GOPRIVATE=$(shell go env GOPRIVATE) \
+		--env GOPROXY=$(shell go env GOPROXY) \
+		--env GOSUMDB=$(shell go env GOSUMDB) \
+		--env VERSION=${VERSION} \
+		--net=host \
+		--rm \
+		--volume /tmp:/tmp \
+		--volume ${HOME}/go:/root/go \
+		--volume $(shell pwd):/workspace \
+		--workdir /workspace \
+			${BUILD_IMAGE_FULLY_QUALIFIED} \
+				make ${COMMAND}
+
+# PHONY
+# ==============================================================================
+# Declare the contents of the PHONY variable as phony. We keep that information
+# in a variable so we can use it in if_changed.
+.PHONY: ${PHONY}

README.md

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+# getidev
+
+`getidev` is a small programme to determine the network interface for an IP
+address.
+
+`getidev` serves as an alternative to `ip route get <ip> | awk ...` because `ip
+route get` can return different output depending on the environment and
+therefore the construct is unsafe.

go.mod

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+module github.com/volker-raschek/getidev
+
+go 1.16

main.go

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+package main
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"strings"
+)
+
+var version string
+
+func main() {
+	ips := os.Args[1:]
+	switch {
+	case len(ips) == 0:
+		log.Fatal("Expect at least one argument")
+	case len(ips) >= 2:
+		log.Fatal("Expect only one argument")
+	}
+
+	ip := strings.Split(ips[0], "/")[0]
+
+	interfaces, err := net.Interfaces()
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+
+	for _, iface := range interfaces {
+		addrs, err := iface.Addrs()
+		if err != nil {
+			log.Fatal(err.Error())
+		}
+
+		for _, addr := range addrs {
+			if strings.Split(addr.String(), "/")[0] == ip {
+				fmt.Fprintln(os.Stdout, iface.Name)
+				return
+			}
+		}
+	}
+
+	os.Exit(1)
+}