#96 Step can pass results of command to another step

README.md

@@ -10,7 +10,7 @@
 
 
 
-Current Version: **1.1.0**
+Current Version: **1.2.0**
 
 Current Release: **Calimero**
 
@@ -101,6 +101,22 @@ but in this case for example first task will block performing on any task and al
 	- ping google.com
 	- -> echo "I need to wait above step to finish, then i can do my stuff"
 
+## Step Pipe
+
+Output from one step can be passed to input of next step:
+
+	name: job1 // name of recipe
+	definition: schedule
+	schedule:
+		min: 0 // every min
+		hour: 0 // every hour
+		day: 0 // every day
+	steps: // steps are done from first to last
+		- echo "Pipe this to next step" }>
+		- cat > piped.txt
+
+As you see, first step is using syntax `}>` at the end, which tells that this command output will be passed to next command input, you can chain like this how much you want.
+Although this is perfectly fine syntax for step `-> echo "Pipe this to next step" }>` (we added async syntax), next step will start even before first step finished and basically nothing will be piped.
 
 ## Installation
 

dist/recipes/job4.yml

@@ -0,0 +1,10 @@
+name: job4 # name of recipe
+definition: schedule
+schedule: 
+    min: 0
+    hour: 0
+    day: 0
+
+steps: # steps are done from first to last
+    - echo "I like golang" }>
+    - cat > i_like_it.txt

tests/configs/config_global_fb.ini

@@ -1,3 +1,4 @@
+error_reporting = false
 # we want to log our errors, and specify where
 error_log = ../tests/var/log/leprechaun/error.log
 # we want to log our info about app to know whats going on

tests/configs/config_regular.ini

@@ -1,3 +1,5 @@
+daemon.error_reporting = false
+
 # we want to log our errors, and specify where
 test.error_log = ../tests/var/log/leprechaun/error.log
 # we want to log our info about app to know whats going on

workers/cmd.go

@@ -0,0 +1,59 @@
+package workers
+
+import (
+	"bytes"
+	"io"
+	"os/exec"
+	"strings"
+)
+
+// PipeMarker is string that we mark when we want to pipe output of results
+// from step command to another step command
+const PipeMarker = "}>"
+
+type cmd struct {
+	stdin  bytes.Buffer
+	cmd    *exec.Cmd
+	stdout bytes.Buffer
+	pipe   bool
+}
+
+func (c *cmd) Run() error {
+	if &c.stdin != nil {
+		in, err := c.cmd.StdinPipe()
+		if err != nil {
+			return err
+		}
+
+		_, err = io.WriteString(in, string(c.stdin.Bytes()))
+		if err != nil {
+			return err
+		}
+	}
+
+	var stderr bytes.Buffer
+	c.cmd.Stdout = &c.stdout
+	c.cmd.Stderr = &stderr
+
+	err := c.cmd.Run()
+
+	return err
+}
+
+// NewCmd build new command and prepare it to be run
+func newCmd(step string, i bytes.Buffer) (*cmd, error) {
+	cmd := &cmd{
+		stdin: i,
+		pipe:  false,
+	}
+
+	s := strings.Fields(step)
+	if s[len(s)-1] == PipeMarker {
+		cmd.pipe = true
+		step = strings.Join(s[:(len(s)-1)], " ")
+	}
+
+	cmd.cmd = exec.Command("bash", "-c", step)
+
+	return cmd, nil
+}

workers/worker.go

@@ -22,13 +22,13 @@ const AsyncMarker = "->"
 type Worker struct {
 	StartedAt      time.Time
 	WorkingOn      string
-	Steps          []string
 	Context        *context.Context
 	Logs           log.Logs
 	DoneChan       chan string
 	ErrorChan      chan Worker
 	TasksPerformed int
 	Cmd            map[string]*exec.Cmd
+	steps          []*cmd
 	Stdout         *os.File
 	Recipe         *recipe.Recipe
 	Err            error
@@ -39,34 +39,48 @@ type Worker struct {
 func (w *Worker) Run() {
 	w.StartedAt = time.Now()
 
-	for _, step := range w.Recipe.GetSteps() {
+	for i, step := range w.Recipe.GetSteps() {
 		w.Logs.Info("Step %s is in progress... \n", step)
-		// replace variables
-		parts := strings.Fields(step)
 
+		if len(step) < 1 {
+			continue
+		}
+
+		parts := strings.Fields(step)
 		if parts[0] == AsyncMarker {
 			step = w.Context.Transpile(strings.Join(parts[1:], " "))
-			go w.workOnStep(step)
+			go w.workOnStep(i, step)
 		} else {
-			step = w.Context.Transpile(step)
-			w.workOnStep(step)
+			w.workOnStep(i, step)
 		}
 	}
 }
 
-func (w *Worker) workOnStep(step string) {
+func (w *Worker) workOnStep(i int, step string) {
 	w.mu.Lock()
-	cmd := exec.Command("bash", "-c", step)
 
-	var stderr bytes.Buffer
-	cmd.Stdout = w.Stdout
-	cmd.Stderr = &stderr
+	var in bytes.Buffer
+	if len(w.steps) > 0 {
+		ps := w.steps[i-1]
+		if ps.pipe {
+			in = ps.stdout
+		}
+	}
+
+	cmd, err := newCmd(step, in)
+	if err != nil {
+		w.Logs.Error(err.Error())
+	}
 
 	w.WorkingOn = step
-	w.Cmd[step] = cmd
+	w.Cmd[step] = cmd.cmd
 	w.mu.Unlock()
 
-	err := cmd.Run()
+	err = cmd.Run()
+
+	w.mu.Lock()
+	w.steps = append(w.steps, cmd)
+	w.mu.Unlock()
 
 	if err != nil {
 		w.mu.Lock()