Moved count related code.

cmd/main.go

@@ -76,6 +76,11 @@ func main() {
 		panic(err)
 	}
 	println(s)
+	c, err := terra.Count(s)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("[Plan] Add: %d, Change: %d, Destroy: %d\n", c.Add, c.Change, c.Destroy)
 
 	println("================")
 	println("================")
@@ -100,6 +105,11 @@ func main() {
 		panic(err)
 	}
 	println(s)
+	c, err = terra.Count(s)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("[Apply] Added: %d, Changed: %d, Destroyed: %d\n", c.Add, c.Change, c.Destroy)
 
 	println("================")
 	println("================")
@@ -126,6 +136,11 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	c, err = terra.Count(s)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("[Destroy] Added: %d, Changed: %d, Destroyed: %d\n", c.Add, c.Change, c.Destroy)
 
 	println("================")
 	println("=== plan =======")
@@ -163,6 +178,11 @@ func main() {
 		panic(err)
 	}
 	println(s)
+	c, err = terra.Count(s)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("[Plan Destroy] Add: %d, Change: %d, Destroy: %d\n", c.Add, c.Change, c.Destroy)
 
 	println("================")
 	println("=== show =======")
@@ -187,4 +207,9 @@ func main() {
 		panic(err)
 	}
 	println(s)
+	c, err = terra.Count(s)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("[Apply Destruction] Added: %d, Changed: %d, Destroyed: %d\n", c.Add, c.Change, c.Destroy)
 }

count.go

@@ -0,0 +1,74 @@
+package terra
+
+import (
+	"errors"
+	"regexp"
+	"strconv"
+)
+
+// ResourceCount represents counts of resources affected by terraform apply/plan/destroy command.
+type ResourceCount struct {
+	Add     int
+	Change  int
+	Destroy int
+}
+
+// Regular expressions for terraform commands stdout pattern matching.
+const (
+	applyRegexp             = `Apply complete! Resources: (\d+) added, (\d+) changed, (\d+) destroyed\.`
+	destroyRegexp           = `Destroy complete! Resources: (\d+) destroyed\.`
+	planWithChangesRegexp   = `(\033\[1m)?Plan:(\033\[0m)? (\d+) to add, (\d+) to change, (\d+) to destroy\.`
+	planWithNoChangesRegexp = `No changes\. Infrastructure is up-to-date\.`
+)
+
+// GetResourceCount parses stdout/stderr of apply/plan/destroy commands and returns number of affected resources.
+func Count(cmdout string) (*ResourceCount, error) {
+	cnt := ResourceCount{}
+
+	terraformCommandPatterns := []struct {
+		regexpStr       string
+		addPosition     int
+		changePosition  int
+		destroyPosition int
+	}{
+		{applyRegexp, 1, 2, 3},
+		{destroyRegexp, -1, -1, 1},
+		{planWithChangesRegexp, 3, 4, 5},
+		{planWithNoChangesRegexp, -1, -1, -1},
+	}
+
+	for _, tc := range terraformCommandPatterns {
+		pattern, err := regexp.Compile(tc.regexpStr)
+		if err != nil {
+			return nil, err
+		}
+
+		matches := pattern.FindStringSubmatch(cmdout)
+		if matches != nil {
+			if tc.addPosition != -1 {
+				cnt.Add, err = strconv.Atoi(matches[tc.addPosition])
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			if tc.changePosition != -1 {
+				cnt.Change, err = strconv.Atoi(matches[tc.changePosition])
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			if tc.destroyPosition != -1 {
+				cnt.Destroy, err = strconv.Atoi(matches[tc.destroyPosition])
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			return &cnt, nil
+		}
+	}
+
+	return nil, errors.New("can't parse Terraform output")
+}