Initial commit

.github/docker-compose-test.yml

@@ -0,0 +1,5 @@
+services:
+  imhost:
+    build: ..
+    ports:
+      - "8080:80"

.github/workflows/docker-test.yml

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+name: Docker Tests
+on:
+    workflow_dispatch:
+    push:
+      branches:
+        - main
+    pull_request:
+
+jobs:
+  docker-test:
+    name: Run tests on latest Go version
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - run: docker compose -f ./.github/docker-compose-test.yml up --build -d
+
+      - run: |
+          curl -sS http://localhost:8080/ | grep Hello\ from\ host
+
+      - run: docker compose -f ./.github/docker-compose-test.yml down --remove-orphans

.github/workflows/golang-ci.yml

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+name: Lint Test
+on:
+    workflow_dispatch:
+    push:
+      branches:
+        - main
+    pull_request:
+
+jobs:
+  golangci-lint:
+    name: Run golangci-lint
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: 'stable'
+
+      # Linting and static analysis
+      - uses: golangci/golangci-lint-action@v4
+        with:
+          version: latest

.github/workflows/unit-test.yml

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+name: Unit Tests
+on:
+    workflow_dispatch:
+    push:
+      branches:
+        - main
+    pull_request:
+
+jobs:
+  go-test:
+    name: Run tests on latest Go version
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version: 'stable'
+
+      # Unit tests
+      - run: go test ./...

.golangci.yml

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+run:
+  tests: true
+  build-tags:
+    - golangci
+  allow-parallel-runners: true
+
+output:
+  sort-results: true
+
+linters:
+  enable-all: true
+  disable:
+  # Disable deprecated/abandoned linters
+  - structcheck
+  - scopelint
+  - ifshort
+  - interfacer
+  - maligned
+  - exhaustivestruct
+  - nosnakecase
+  - varcheck
+  - deadcode
+  - golint
+  # Allow global variables
+  - gochecknoglobals
+  # Disable due to use of external linters
+  - depguard

Dockerfile

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+# -----------------------------------------------------------------------------
+#  Build Stage
+# -----------------------------------------------------------------------------
+FROM golang:alpine AS builder
+
+COPY . /go/src/app
+ENV CGO_ENABLED 0
+
+WORKDIR /go/src/app
+
+RUN go mod download && \
+    go mod verify && \
+    go test -v ./...
+
+RUN go build \
+    -ldflags="-s -w -extldflags \"-static\"" \
+    -o /go/bin/mywebapp \
+    /go/src/app/imhost/main.go
+
+# -----------------------------------------------------------------------------
+#  Main Stage
+# -----------------------------------------------------------------------------
+FROM scratch
+
+COPY --from=builder /go/bin/mywebapp /usr/bin/mywebapp
+EXPOSE 80/tcp
+WORKDIR /tmp
+ENTRYPOINT [ "/usr/bin/mywebapp" ]
+
+HEALTHCHECK \
+    --start-period=15s \
+    --interval=5m \
+    --timeout=15s \
+    --retries=3 \
+    CMD [ "/usr/bin/mywebapp", "--ping"]

LICENSE

@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <https://unlicense.org>

README.md

@@ -0,0 +1,19 @@
+# ImHost
+
+ImHost is a simple Docker image that simply returns the hostname of the container it is running in.
+
+Its aim is to be used for testing and debugging purposes in a Docker orchestration environment. Such as docker-compose, docker-swarm, kubernetes, etc.
+
+## Usage
+
+- Build the image
+
+```bash
+docker build -t imhost https://github.com/KEINOS/imhost.git
+```
+
+- Run the container (expose the port 80 to 8088)
+
+```bash
+docker run --rm -p 8088:80 imhost
+```

go.mod

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+module github.com/KEINOS/iamhost
+
+go 1.22.1
+
+require (
+	github.com/stretchr/testify v1.9.0
+	github.com/zenizh/go-capturer v0.0.0-20211219060012-52ea6c8fed04
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/zenizh/go-capturer v0.0.0-20211219060012-52ea6c8fed04 h1:qXafrlZL1WsJW5OokjraLLRURHiw0OzKHD/RNdspp4w=
+github.com/zenizh/go-capturer v0.0.0-20211219060012-52ea6c8fed04/go.mod h1:FiwNQxz6hGoNFBC4nIx+CxZhI3nne5RmIOlT/MXcSD4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

imhost/main.go

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+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	listenPort    = "80" // Listen port
+	srvTimeoutSec = 20   // Server timeout
+	FAILURE       = 1    // Exit code for failure
+	SUCCESS       = 0    // Exit code for success
+)
+
+// Monkey patching for testing.
+var (
+	// osExit is a copy of os.Exit that can be mocked in tests.
+	osExit = os.Exit
+	// osHostname is a copy of os.Hostname that can be mocked in tests.
+	osHostname = os.Hostname
+)
+
+// ----------------------------------------------------------------------------
+//  Main
+// ----------------------------------------------------------------------------
+
+//nolint:forbidigo // allow fmt.Print* due to its nature
+func main() {
+	addr := "0.0.0.0:" + listenPort
+	url := "http://" + addr
+	handler := new(defaultHandler)
+
+	// If the args contain --ping, do a health check and exit
+	healthCheck(url)
+
+	// Start server
+	fmt.Println("* Starging up server ...")
+	fmt.Printf("* Listening to: %s\n", url)
+
+	log.Fatal(spawnServer(addr, handler))
+}
+
+func spawnServer(addr string, handler http.Handler) error {
+	srv := new(http.Server)
+
+	srv.Addr = addr
+	srv.Handler = handler
+	srv.ReadHeaderTimeout = srvTimeoutSec * time.Second
+
+	return errors.Wrap(srv.ListenAndServe(), "failed to start server")
+}
+
+// ----------------------------------------------------------------------------
+//  Type: defaultHandler (implements http.Handler)
+// ----------------------------------------------------------------------------
+
+// defaultHandler is a "catch all" handler that responds with a message
+// containing the hostname of the server.
+type defaultHandler struct{}
+
+// ServeHTTP writes a message containing the hostname of the server to the
+// response writer.
+// This is an implementation of the http.Handler interface.
+func (h *defaultHandler) ServeHTTP(respWriter http.ResponseWriter, _ *http.Request) {
+	var respMsg string
+
+	status := http.StatusOK
+
+	hostname, err := osHostname()
+	if err != nil {
+		respMsg = fmt.Sprintf("failed to get hostname. error: %s", err)
+		status = http.StatusInternalServerError
+	} else {
+		respMsg = fmt.Sprintf("Hello from host: %s\n", hostname)
+	}
+
+	respWriter.WriteHeader(status)
+
+	if _, err := respWriter.Write([]byte(respMsg)); err != nil {
+		panic(err)
+	}
+}
+
+// ----------------------------------------------------------------------------
+//  Functions
+// ----------------------------------------------------------------------------
+
+// healthCheck exits if the --ping flag is set. Otherwise it will do nothing.
+//
+// If the --ping flag is set, it will:
+// Make a request to the local server and check if it is running. It will exit
+// with a status code of 0 if the server is running, and 1 if it is not.
+func healthCheck(rawURL string) {
+	if !strings.Contains(strings.Join(os.Args, " "), "--ping") {
+		return
+	}
+
+	ctx, doCancel := context.WithTimeout(context.Background(), srvTimeoutSec*time.Second)
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
+	if err != nil {
+		doCancel()
+		fmt.Fprintln(os.Stderr, err)
+		osExit(FAILURE)
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		doCancel()
+		fmt.Fprintln(os.Stderr, err)
+		osExit(FAILURE)
+	}
+
+	resp.Body.Close()
+	doCancel()
+
+	osExit(SUCCESS)
+}