From 5c66c7186406e8c5e28aadb818dd8a2cb75b8442 Mon Sep 17 00:00:00 2001 From: Maksim Nabokikh Date: Wed, 7 Aug 2024 19:31:01 +0200 Subject: [PATCH] Change workdir for gomplate (#3684) Workaround to run gomplate from a non-root directory in distroless images, because gomplate tries to access CWD on start. See: https://github.com/hairyhenderson/gomplate/pull/2202 Signed-off-by: m.nabokikh --- cmd/docker-entrypoint/main.go | 46 ++++++++++------- cmd/docker-entrypoint/main_test.go | 79 +++++++++++++----------------- 2 files changed, 62 insertions(+), 63 deletions(-) diff --git a/cmd/docker-entrypoint/main.go b/cmd/docker-entrypoint/main.go index b0f8e277f3..14d837e5ee 100644 --- a/cmd/docker-entrypoint/main.go +++ b/cmd/docker-entrypoint/main.go @@ -22,20 +22,13 @@ func main() { os.Exit(1) } - if err := run(args, realExec, realWhich); err != nil { + if err := run(args, realExec, realWhich, realGomplate); err != nil { fmt.Println("error:", err.Error()) os.Exit(1) } } -func realExec(fork bool, args ...string) error { - if fork { - if output, err := exec.Command(args[0], args[1:]...).CombinedOutput(); err != nil { - return fmt.Errorf("cannot fork/exec command %s: %w (output: %q)", args, err, string(output)) - } - return nil - } - +func realExec(args ...string) error { argv0, err := exec.LookPath(args[0]) if err != nil { return fmt.Errorf("cannot lookup path for command %s: %w", args[0], err) @@ -56,34 +49,49 @@ func realWhich(path string) string { return fullPath } -func run(args []string, execFunc func(bool, ...string) error, whichFunc func(string) string) error { +func realGomplate(path string) (string, error) { + tmpFile, err := os.CreateTemp("/tmp", "dex.config.yaml-*") + if err != nil { + return "", fmt.Errorf("cannot create temp file: %w", err) + } + + cmd := exec.Command("gomplate", "-f", path, "-o", tmpFile.Name()) + // TODO(nabokihms): Workaround to run gomplate from a non-root directory in distroless images + // gomplate tries to access CWD on start, see: https://github.com/hairyhenderson/gomplate/pull/2202 + cmd.Dir = "/etc/dex" + + output, err := cmd.CombinedOutput() + if err != nil { + return "", fmt.Errorf("error executing gomplate: %w, (output: %q)", err, string(output)) + } + + return tmpFile.Name(), nil +} + +func run(args []string, execFunc func(...string) error, whichFunc func(string) string, gomplateFunc func(string) (string, error)) error { if args[0] != "dex" && args[0] != whichFunc("dex") { - return execFunc(false, args...) + return execFunc(args...) } if args[1] != "serve" { - return execFunc(false, args...) + return execFunc(args...) } newArgs := []string{} for _, tplCandidate := range args { if hasSuffixes(tplCandidate, ".tpl", ".tmpl", ".yaml") { - tmpFile, err := os.CreateTemp("/tmp", "dex.config.yaml-*") + fileName, err := gomplateFunc(tplCandidate) if err != nil { - return fmt.Errorf("cannot create temp file: %w", err) - } - - if err := execFunc(true, "gomplate", "-f", tplCandidate, "-o", tmpFile.Name()); err != nil { return err } - newArgs = append(newArgs, tmpFile.Name()) + newArgs = append(newArgs, fileName) } else { newArgs = append(newArgs, tplCandidate) } } - return execFunc(false, newArgs...) + return execFunc(newArgs...) } func hasSuffixes(s string, suffixes ...string) bool { diff --git a/cmd/docker-entrypoint/main_test.go b/cmd/docker-entrypoint/main_test.go index c8aef16979..49da3b5f02 100644 --- a/cmd/docker-entrypoint/main_test.go +++ b/cmd/docker-entrypoint/main_test.go @@ -6,7 +6,7 @@ import ( ) type execArgs struct { - fork bool + gomplate bool argPrefixes []string } @@ -16,98 +16,89 @@ func TestRun(t *testing.T) { args []string execReturns error whichReturns string - wantExecArgs []execArgs + wantExecArgs execArgs wantErr error }{ { name: "executable not dex", args: []string{"tuna", "fish"}, - wantExecArgs: []execArgs{{fork: false, argPrefixes: []string{"tuna", "fish"}}}, + wantExecArgs: execArgs{gomplate: false, argPrefixes: []string{"tuna", "fish"}}, }, { name: "executable is full path to dex", args: []string{"/usr/local/bin/dex", "marshmallow", "zelda"}, whichReturns: "/usr/local/bin/dex", - wantExecArgs: []execArgs{{fork: false, argPrefixes: []string{"/usr/local/bin/dex", "marshmallow", "zelda"}}}, + wantExecArgs: execArgs{gomplate: false, argPrefixes: []string{"/usr/local/bin/dex", "marshmallow", "zelda"}}, }, { name: "command is not serve", args: []string{"dex", "marshmallow", "zelda"}, - wantExecArgs: []execArgs{{fork: false, argPrefixes: []string{"dex", "marshmallow", "zelda"}}}, + wantExecArgs: execArgs{gomplate: false, argPrefixes: []string{"dex", "marshmallow", "zelda"}}, }, { name: "no templates", args: []string{"dex", "serve", "config.yaml.not-a-template"}, - wantExecArgs: []execArgs{{fork: false, argPrefixes: []string{"dex", "serve", "config.yaml.not-a-template"}}}, + wantExecArgs: execArgs{gomplate: false, argPrefixes: []string{"dex", "serve", "config.yaml.not-a-template"}}, }, { name: "no templates", args: []string{"dex", "serve", "config.yaml.not-a-template"}, - wantExecArgs: []execArgs{{fork: false, argPrefixes: []string{"dex", "serve", "config.yaml.not-a-template"}}}, + wantExecArgs: execArgs{gomplate: false, argPrefixes: []string{"dex", "serve", "config.yaml.not-a-template"}}, }, { - name: ".tpl template", - args: []string{"dex", "serve", "config.tpl"}, - wantExecArgs: []execArgs{ - {fork: true, argPrefixes: []string{"gomplate", "-f", "config.tpl", "-o", "/tmp/dex.config.yaml-"}}, - {fork: false, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, - }, + name: ".tpl template", + args: []string{"dex", "serve", "config.tpl"}, + wantExecArgs: execArgs{gomplate: true, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, }, { - name: ".tmpl template", - args: []string{"dex", "serve", "config.tmpl"}, - wantExecArgs: []execArgs{ - {fork: true, argPrefixes: []string{"gomplate", "-f", "config.tmpl", "-o", "/tmp/dex.config.yaml-"}}, - {fork: false, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, - }, + name: ".tmpl template", + args: []string{"dex", "serve", "config.tmpl"}, + wantExecArgs: execArgs{gomplate: true, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, }, { - name: ".yaml template", - args: []string{"dex", "serve", "some/path/config.yaml"}, - wantExecArgs: []execArgs{ - {fork: true, argPrefixes: []string{"gomplate", "-f", "some/path/config.yaml", "-o", "/tmp/dex.config.yaml-"}}, - {fork: false, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, - }, + name: ".yaml template", + args: []string{"dex", "serve", "some/path/config.yaml"}, + wantExecArgs: execArgs{gomplate: true, argPrefixes: []string{"dex", "serve", "/tmp/dex.config.yaml-"}}, }, } for _, test := range tests { t.Run(test.name, func(t *testing.T) { - var gotExecForks []bool - var gotExecArgs [][]string - fakeExec := func(fork bool, args ...string) error { - gotExecForks = append(gotExecForks, fork) - gotExecArgs = append(gotExecArgs, args) + var gotExecArgs []string + var runsGomplate bool + + fakeExec := func(args ...string) error { + gotExecArgs = append(args, gotExecArgs...) return test.execReturns } fakeWhich := func(_ string) string { return test.whichReturns } - gotErr := run(test.args, fakeExec, fakeWhich) + fakeGomplate := func(file string) (string, error) { + runsGomplate = true + return "/tmp/dex.config.yaml-", nil + } + + gotErr := run(test.args, fakeExec, fakeWhich, fakeGomplate) if (test.wantErr == nil) != (gotErr == nil) { t.Errorf("wanted error %s, got %s", test.wantErr, gotErr) } - if !execArgsMatch(test.wantExecArgs, gotExecForks, gotExecArgs) { - t.Errorf("wanted exec args %+v, got %+v %+v", test.wantExecArgs, gotExecForks, gotExecArgs) + + if !execArgsMatch(test.wantExecArgs, runsGomplate, gotExecArgs) { + t.Errorf("wanted exec args %+v (running gomplate: %+v), got %+v (running gomplate: %+v)", + test.wantExecArgs.argPrefixes, test.wantExecArgs.gomplate, gotExecArgs, runsGomplate) } }) } } -func execArgsMatch(wantExecArgs []execArgs, gotForks []bool, gotExecArgs [][]string) bool { - if len(wantExecArgs) != len(gotForks) { +func execArgsMatch(wantExecArgs execArgs, gomplate bool, gotExecArgs []string) bool { + if wantExecArgs.gomplate != gomplate { return false } - - for i := range wantExecArgs { - if wantExecArgs[i].fork != gotForks[i] { + for i := range wantExecArgs.argPrefixes { + if !strings.HasPrefix(gotExecArgs[i], wantExecArgs.argPrefixes[i]) { return false } - for j := range wantExecArgs[i].argPrefixes { - if !strings.HasPrefix(gotExecArgs[i][j], wantExecArgs[i].argPrefixes[j]) { - return false - } - } } - return true }