Fix profiler path (#339)

Co-authored-by: CrazyMax <crazy-max@users.noreply.github.com>

Dockerfile

@@ -39,7 +39,8 @@ RUN apk --update --no-cache add \
 COPY --from=build /usr/local/bin/diun /usr/local/bin/diun
 RUN diun --version
 
-ENV DIUN_DB_PATH="/data/diun.db"
+ENV PROFILER_PATH="/profiler" \
+  DIUN_DB_PATH="/data/diun.db"
 
-VOLUME [ "/data" ]
+VOLUME [ "/data", "/profiler" ]
 ENTRYPOINT [ "diun" ]

cmd/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"os/signal"
+	"path"
 	"runtime"
 	"strings"
 	"syscall"
@@ -77,8 +78,12 @@ func main() {
 	log.Debug().Msg(cfg.String())
 
 	// Profiler
-	if len(cli.Profiler) > 0 {
-		profilePath := profile.ProfilePath(cfg.Db.Path)
+	if len(cli.Profiler) > 0 && len(cli.ProfilerPath) > 0 {
+		profilerPath := path.Clean(cli.ProfilerPath)
+		if err = os.MkdirAll(profilerPath, os.ModePerm); err != nil {
+			log.Fatal().Err(err).Msg("Cannot create profiler folder")
+		}
+		profilePath := profile.ProfilePath(profilerPath)
 		switch cli.Profiler {
 		case "cpu":
 			defer profile.Start(profile.CPUProfile, profilePath).Stop()

docs/faq.md

@@ -121,3 +121,37 @@ regopts:
 ```
 
 Or you can tweak the [`schedule` setting](config/watch.md#schedule) with something like `0 */6 * * *` (every 6 hours).
+
+## Profiling
+
+Diun provides a simple way to manage runtime/pprof profiling through [`--profiler-path` and `--profiler` flags](usage/cli.md#options):
+
+```yaml
+version: "3.5"
+
+services:
+  diun:
+    image: crazymax/diun:latest
+    volumes:
+      - "./data:/data"
+      - "./profiler:/profiler"
+      - "/var/run/docker.sock:/var/run/docker.sock"
+    environment:
+      - "TZ=Europe/Paris"
+      - "LOG_LEVEL=info"
+      - "PROFILER_PATH=/profiler"
+      - "PROFILER=mem"
+      - "DIUN_PROVIDERS_DOCKER=true"
+    restart: always
+```
+
+Following profilers are available:
+
+* `cpu` enables cpu profiling
+* `mem` enables memory profiling
+* `alloc` enables memory profiling and changes which type of memory to profile allocations
+* `heap` enables memory profiling and changes which type of memory profiling to profile the heap
+* `routines` enables goroutine profiling
+* `mutex` enables mutex profiling
+* `threads` enables thread creation profiling
+* `block` enables block (contention) profiling

docs/usage/cli.md

@@ -18,6 +18,8 @@ Flags:
   -h, --help                    Show context-sensitive help.
       --version
       --config=STRING           Diun configuration file ($CONFIG).
+      --profiler-path=STRING    Base path where profiling files are written
+                                ($PROFILER_PATH).
       --profiler=STRING         Profiler to use ($PROFILER).
       --log-level="info"        Set log level ($LOG_LEVEL).
       --log-json                Enable JSON logging output ($LOG_JSON).
@@ -34,7 +36,8 @@ Following environment variables can be used in place:
 | Name               | Default       | Description   |
 |--------------------|---------------|---------------|
 | `CONFIG`           |               | Diun configuration file |
-| `PROFILER`         |               | Profiler to use |
+| `PROFILER_PATH`    |               | Base path where profiling files are written |
+| `PROFILER`         |               | [Profiler](../faq.md#profiling) to use |
 | `LOG_LEVEL`        | `info`        | Log level output |
 | `LOG_JSON`         | `false`       | Enable JSON logging output |
 | `LOG_CALLER`       | `false`       | Enable to add `file:line` of the caller |

internal/model/cli.go

@@ -6,6 +6,7 @@ import "github.com/alecthomas/kong"
 type Cli struct {
 	Version      kong.VersionFlag
 	Cfgfile      string `kong:"name='config',env='CONFIG',help='Diun configuration file.'"`
+	ProfilerPath string `kong:"name='profiler-path',env='PROFILER_PATH',help='Base path where profiling files are written.'"`
 	Profiler     string `kong:"name='profiler',env='PROFILER',enum='cpu,mem,alloc,heap,routines,mutex,threads,block',help='Profiler to use.'"`
 	LogLevel     string `kong:"name='log-level',env='LOG_LEVEL',default='info',help='Set log level.'"`
 	LogJSON      bool   `kong:"name='log-json',env='LOG_JSON',default='false',help='Enable JSON logging output.'"`