initial commit

Makefile

@@ -0,0 +1,80 @@
+VERSION := $(shell jq -r .version <package.json)
+
+APP      := $(shell jq -r .name <package.json)
+PACKAGES := $(shell go list -f {{.Dir}} ./...)
+GOFILES  := $(addsuffix /*.go,$(PACKAGES))
+GOFILES  := $(wildcard $(GOFILES))
+
+.PHONY: clean release README.md
+
+clean:
+	rm -rf binaries/
+	rm -rf release/
+
+release-exists:
+	hub release show "$(VERSION)"
+
+release: README.md zip
+	git add package.json
+	git add README.md
+	git add Makefile
+	git commit -am "Release $(VERSION)" || true
+	git push
+	hub release create $(VERSION) -m "$(VERSION)" -a release/$(APP)_$(VERSION)_osx_x86_64.tar.gz -a release/$(APP)_$(VERSION)_windows_x86_64.zip -a release/$(APP)_$(VERSION)_linux_x86_64.tar.gz -a release/$(APP)_$(VERSION)_osx_x86_32.tar.gz -a release/$(APP)_$(VERSION)_windows_x86_32.zip -a release/$(APP)_$(VERSION)_linux_x86_32.tar.gz -a release/$(APP)_$(VERSION)_linux_arm64.tar.gz
+
+README.md:
+	go get github.com/keilerkonzept/$(APP) && <README.template.md subst \
+		VERSION="$(VERSION)" APP="$(APP)" USAGE="$$($(APP) -h 2>&1)" > README.md
+
+zip: release/$(APP)_$(VERSION)_osx_x86_64.tar.gz release/$(APP)_$(VERSION)_windows_x86_64.zip release/$(APP)_$(VERSION)_linux_x86_64.tar.gz release/$(APP)_$(VERSION)_osx_x86_32.tar.gz release/$(APP)_$(VERSION)_windows_x86_32.zip release/$(APP)_$(VERSION)_linux_x86_32.tar.gz release/$(APP)_$(VERSION)_linux_arm64.tar.gz
+
+binaries: binaries/osx_x86_64/$(APP) binaries/windows_x86_64/$(APP).exe binaries/linux_x86_64/$(APP) binaries/osx_x86_32/$(APP) binaries/windows_x86_32/$(APP).exe binaries/linux_x86_32/$(APP)
+
+release/$(APP)_$(VERSION)_osx_x86_64.tar.gz: binaries/osx_x86_64/$(APP)
+	mkdir -p release
+	tar cfz release/$(APP)_$(VERSION)_osx_x86_64.tar.gz -C binaries/osx_x86_64 $(APP)
+
+binaries/osx_x86_64/$(APP): $(GOFILES)
+	GOOS=darwin GOARCH=amd64 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/osx_x86_64/$(APP) .
+
+release/$(APP)_$(VERSION)_windows_x86_64.zip: binaries/windows_x86_64/$(APP).exe
+	mkdir -p release
+	cd ./binaries/windows_x86_64 && zip -r -D ../../release/$(APP)_$(VERSION)_windows_x86_64.zip $(APP).exe
+
+binaries/windows_x86_64/$(APP).exe: $(GOFILES)
+	GOOS=windows GOARCH=amd64 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/windows_x86_64/$(APP).exe .
+
+release/$(APP)_$(VERSION)_linux_x86_64.tar.gz: binaries/linux_x86_64/$(APP)
+	mkdir -p release
+	tar cfz release/$(APP)_$(VERSION)_linux_x86_64.tar.gz -C binaries/linux_x86_64 $(APP)
+
+binaries/linux_x86_64/$(APP): $(GOFILES)
+	GOOS=linux GOARCH=amd64 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/linux_x86_64/$(APP) .
+
+release/$(APP)_$(VERSION)_osx_x86_32.tar.gz: binaries/osx_x86_32/$(APP)
+	mkdir -p release
+	tar cfz release/$(APP)_$(VERSION)_osx_x86_32.tar.gz -C binaries/osx_x86_32 $(APP)
+
+binaries/osx_x86_32/$(APP): $(GOFILES)
+	GOOS=darwin GOARCH=386 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/osx_x86_32/$(APP) .
+
+release/$(APP)_$(VERSION)_windows_x86_32.zip: binaries/windows_x86_32/$(APP).exe
+	mkdir -p release
+	cd ./binaries/windows_x86_32 && zip -r -D ../../release/$(APP)_$(VERSION)_windows_x86_32.zip $(APP).exe
+
+binaries/windows_x86_32/$(APP).exe: $(GOFILES)
+	GOOS=windows GOARCH=386 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/windows_x86_32/$(APP).exe .
+
+release/$(APP)_$(VERSION)_linux_x86_32.tar.gz: binaries/linux_x86_32/$(APP)
+	mkdir -p release
+	tar cfz release/$(APP)_$(VERSION)_linux_x86_32.tar.gz -C binaries/linux_x86_32 $(APP)
+
+binaries/linux_x86_32/$(APP): $(GOFILES)
+	GOOS=linux GOARCH=386 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/linux_x86_32/$(APP) .
+
+release/$(APP)_$(VERSION)_linux_arm64.tar.gz: binaries/linux_arm64/$(APP)
+	mkdir -p release
+	tar cfz release/$(APP)_$(VERSION)_linux_arm64.tar.gz -C binaries/linux_arm64 $(APP)
+
+binaries/linux_arm64/$(APP): $(GOFILES)
+	GOOS=linux GOARCH=arm64 go build -ldflags "-X main.version=$(VERSION) -X main.app=$(APP)" -o binaries/linux_arm64/$(APP) .

README.md

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+# wait-for-cron-expression-match
+
+A tiny tool that waits until a given cron expression would trigger, and then just exits. If multiple expressions are given, it waits until the _first_ (earliest) match.
+
+## Example
+
+
+```sh
+$ wait-for-cron-expression-match "*/5 * * * * *"
+2020/07/08 17:57:17 waiting 2.998536s until next match (2020-07-08T17:57:20+02:00) of cron expression "*/5 * * * * *"
+$ # 2.998s later
+```
+
+## Contents
+
+- [Get it](#get-it)
+- [Usage](#usage)
+
+## Get it
+
+Using go get:
+
+```bash
+go get -u github.com/keilerkonzept/wait-for-cron-expression-match
+```
+
+Or [download the binary for your platform](https://github.com/keilerkonzept/wait-for-cron-expression-match/releases/latest) from the releases page.
+
+## Usage
+
+```text
+wait-for-cron-expression-match [CRON_EXPRESSION [CRON_EXPRESSIONS...]]
+```

README.template.md

@@ -0,0 +1,33 @@
+# ${APP}
+
+A tiny tool that waits until a given cron expression would trigger, and then just exits. If multiple expressions are given, it waits until the _first_ (earliest) match.
+
+## Example
+
+
+```sh
+$ ${APP} "*/5 * * * * *"
+2020/07/08 17:57:17 waiting 2.998536s until next match (2020-07-08T17:57:20+02:00) of cron expression "*/5 * * * * *"
+$ # 2.998s later
+```
+
+## Contents
+
+- [Get it](#get-it)
+- [Usage](#usage)
+
+## Get it
+
+Using go get:
+
+```bash
+go get -u github.com/keilerkonzept/${APP}
+```
+
+Or [download the binary for your platform](https://github.com/keilerkonzept/${APP}/releases/latest) from the releases page.
+
+## Usage
+
+```text
+${APP} [CRON_EXPRESSION [CRON_EXPRESSIONS...]]
+```

go.mod

@@ -0,0 +1,5 @@
+module github.com/keilerkonzept/wait-for-cron-expression-match
+
+go 1.14
+
+require github.com/robfig/cron v1.2.0

go.sum

@@ -0,0 +1,2 @@
+github.com/robfig/cron v1.2.0 h1:ZjScXvvxeQ63Dbyxy76Fj3AT3Ut0aKsyd2/tl3DTMuQ=
+github.com/robfig/cron v1.2.0/go.mod h1:JGuDeoQd7Z6yL4zQhZ3OPEVHB7fL6Ka6skscFHfmt2k=

main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/robfig/cron"
+)
+
+var config struct {
+	cronExpressions    []string
+	schedules          []cron.Schedule
+	evaluationInterval time.Duration
+}
+
+var app = "wait-for-cron-expression-match"
+
+func init() {
+	log.SetFlags(log.Ltime | log.Ldate | log.Lmicroseconds)
+	log.SetPrefix(fmt.Sprintf("[%s] ", app))
+	flag.Parse()
+
+	config.evaluationInterval = 250 * time.Millisecond
+	config.cronExpressions = flag.Args()
+
+	if len(config.cronExpressions) == 0 {
+		log.Fatal("at least one expression is required")
+	}
+	for _, e := range config.cronExpressions {
+		schedule, err := cron.Parse(e)
+		if err != nil {
+			log.Fatalf("parse cron expression %q: %v", e, err)
+		}
+		config.schedules = append(config.schedules, schedule)
+	}
+}
+
+func main() {
+	now := time.Now()
+	tickInterval := config.evaluationInterval
+	var next time.Time
+	for i, s := range config.schedules {
+		nextNew := s.Next(now)
+		if i == 0 || nextNew.Before(next) {
+			next = nextNew
+		}
+	}
+	delta := next.Sub(now)
+	if delta < tickInterval {
+		tickInterval = delta
+	}
+	tick := time.Tick(tickInterval)
+
+	plural := ""
+	if len(config.cronExpressions) > 1 {
+		plural = "s"
+	}
+	log.Printf("waiting %v until next match (%v) of cron expression%s %q", delta, next.Format(time.RFC3339Nano), plural, config.cronExpressions)
+	defer log.Print("done")
+	for now = range tick {
+		if now.After(next) {
+			return
+		}
+	}
+}

package.json

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+{
+    "name": "wait-for-cron-expression-match",
+    "version": "0.0.1"
+}

renovate.json

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+{
+  "extends": [
+    "config:base"
+  ],
+  "automerge": true
+}