Patch 1 + Patch 2

.dockerignore

@@ -0,0 +1,7 @@
+docker-stats-on-exit-shim
+
+# Vim swap files
+.*.swp
+.gitignore
+.travis.yml
+Dockerfile

Dockerfile

@@ -0,0 +1,21 @@
+FROM golang:1.12 as builder
+RUN go get -u github.com/golang/dep/...
+
+WORKDIR $GOPATH/src/github.com/delcypher/docker-stats-on-exit-shim
+
+COPY Gopkg.toml .
+COPY main.go .
+
+RUN dep ensure
+
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o /docker-stats-on-exit-shim
+
+FROM alpine:latest
+
+WORKDIR /
+
+COPY --from=builder /docker-stats-on-exit-shim .
+
+ENTRYPOINT ["/docker-stats-on-exit-shim"]
+
+CMD ["sleep", "1"]

Gopkg.toml

@@ -0,0 +1,4 @@
+
+[[override]]
+  name = "github.com/opencontainers/runc"
+  revision = "a2a6e82"

README.md

@@ -10,12 +10,23 @@ real command by waiting for it to exit and then querying the active Cgroup subsy
 to gather their statistics. It dumps these statistics to a file as JSON and then exits
 with the exit code of the real command.
 
-## Example
+## Environment variables
+- `STATS_OUTPUT_FILE=/dev/stdout` file path you want your output to be saved to (Default /dev/stdout)
+- `STATS_OUTPUT_PREFIX=` any prefix you want to add before stats output (Default blank)
+- `STATS_OUTPUT_MINIFIED=false` true|false (Default true)
 
+## Example
+Dockerfile
+```
+COPY --from=hasnat/docker-stats-on-exit-shim /docker-stats-on-exit-shim .
+ENTRYPOINT ["/docker-stats-on-exit-shim"]
+CMD ["sleep", "1"]
+```
+Example Run
 ```bash
-$ docker run --rm -ti -v`pwd`:/tmp/:rw ubuntu /tmp/docker-stats-on-exit-shim /tmp/output.json /bin/sleep 1
-$ cat output.json
+$ docker run --rm -ti hasnat/docker-stats-on-exit-shim /bin/sleep 1
 ```
+Output example
 ```json
 {
   "wall_time": 1000765975,
@@ -53,10 +64,7 @@ $ cat output.json
 mkdir -p src/github.com/delcypher
 export GOPATH=`pwd`
 cd src/github.com/delcypher
-git clone git@github.com:delcypher/docker-stats-on-exit-shim.git
-cd docker-stats-on-exit-shim
-git submodule init && git submodule update
-go get .
+dep ensure
 go build
 ```
 

main.go

@@ -21,15 +21,15 @@ import (
   "os/signal"
   "syscall"
   "time"
+  "strconv"
   cgroups "github.com/opencontainers/runc/libcontainer/cgroups"
   cgroups_fs "github.com/opencontainers/runc/libcontainer/cgroups/fs"
 )
 
 func printUsage() {
-  fmt.Printf("%s <stats_file> <command> [arg...]\n", os.Args[0])
-  fmt.Println("")
+  fmt.Printf("%s <command> [arg...]\n", os.Args[0])
+  fmt.Println("environment variables STATS_OUTPUT_FILE=/dev/stdout STATS_OUTPUT_MINIFIED=false STATS_OUTPUT_PREFIX=")
   fmt.Println("Runs <command> and on termination outputs cgroup usage information")
-  fmt.Println("as JSON to <stats_file>")
 }
 
 type Stats struct {
@@ -62,16 +62,24 @@ func fail(template string, args ...interface{}) {
   os.Exit(FailExitCode)
 }
 
+func getEnv(key, defaultValue string) string {
+  value := os.Getenv(key)
+  if len(value) == 0 {
+    return defaultValue
+  }
+  return value
+}
+
 func main() {
   exitCode := 0;
 
-  if len(os.Args) < 3 {
+  if len(os.Args) < 2 {
     printUsage()
     os.Exit(1)
   }
 
   // Open file for writing stats
-  f, err := os.Create(os.Args[1])
+  f, err := os.Create(getEnv("STATS_OUTPUT_FILE", "/dev/stdout"))
   if err != nil {
     fail("Failed to create stats file %s: %s\n", os.Args[1], err)
   }
@@ -109,7 +117,7 @@ func main() {
 
 
   // Run the subproccess
-  cmd := exec.Command(os.Args[2], os.Args[3:]...)
+  cmd := exec.Command(os.Args[1], os.Args[2:]...)
   cmd.Stdin = os.Stdin
   cmd.Stdout = os.Stdout
   cmd.Stderr = os.Stderr
@@ -168,10 +176,21 @@ func main() {
   }
 
   //fmt.Printf("Stats: %+v", combinedStats)
-  statsAsBytes, err := json.MarshalIndent(&combinedStats, "", "  ")
+  statsPrefix := getEnv("STATS_OUTPUT_PREFIX", "")
+  minified := false
+  minified, _ = strconv.ParseBool(getEnv("STATS_OUTPUT_MINIFIED", "false"))
+  var statsAsBytes []byte
+  if minified {
+    statsAsBytes, err = json.Marshal(&combinedStats)
+  } else {
+    statsAsBytes, err = json.MarshalIndent(&combinedStats, "", "  ")
+  }
+
   if err != nil {
     fail("Failed to serialize stats to JSON: %s\n", err)
   }
+
+  _, err = f.Write([]byte(statsPrefix))
   _, err = f.Write(statsAsBytes)
   if err != nil {
     fail("Failed to write stats to file: %s\n", err)