Merge pull request #12 from golift/dn2_context

Add context inputs for exec.Cmd

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023 Go Lift - Building Strong Go Tools
+Copyright (c) 2019-2023 Go Lift - Building Strong Go Tools
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

encode.go

@@ -4,13 +4,14 @@
 package ffmpeg
 
 import (
-	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"os/exec"
 	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 )
 
 // Default, Maximum and Minimum Values for encoder configuration. Change these if your needs differ.
@@ -173,7 +174,7 @@ func (e *Encoder) SetSize(size string) int64 {
 
 // getVideoHandle is a helper function that creates and returns an ffmpeg command.
 // This is used by higher level function to cobble together an input stream.
-func (e *Encoder) getVideoHandle(input, output, title string) (string, *exec.Cmd) {
+func (e *Encoder) getVideoHandle(ctx context.Context, input, output, title string) (string, *exec.Cmd) {
 	if title == "" {
 		title = filepath.Base(output)
 	}
@@ -220,18 +221,38 @@ func (e *Encoder) getVideoHandle(input, output, title string) (string, *exec.Cmd
 
 	arg = append(arg, output) // save file path goes last.
 
-	return strings.Join(arg, " "), exec.Command(arg[0], arg[1:]...) //nolint:Gosec
+	return strings.Join(arg, " "), exec.CommandContext(ctx, arg[0], arg[1:]...) //nolint:Gosec
 }
 
 // GetVideo retreives video from an input and returns an io.ReadCloser to consume the output.
 // Input must be an RTSP URL. Title is encoded into the video as the "movie title."
 // Returns command used, io.ReadCloser and error or nil.
+// This will automatically create a context with a timeout equal to the time duration requested plus 1 second.
+// If no time duration is requested the context has no timeout.
+// If you want to control the context, use GetVideoContext().
 func (e *Encoder) GetVideo(input, title string) (string, io.ReadCloser, error) {
+	ctx := context.Background()
+
+	if e.config.Time > 0 {
+		var cancel func()
+
+		ctx, cancel = context.WithTimeout(ctx, time.Second*time.Duration(e.config.Time+1))
+		defer cancel()
+	}
+
+	return e.GetVideoContext(ctx, input, title)
+}
+
+// GetVideoContext retreives video from an input and returns an io.ReadCloser to consume the output.
+// Input must be an RTSP URL. Title is encoded into the video as the "movie title."
+// Returns command used, io.ReadCloser and error or nil.
+// Use the context to add a timeout value (max run duration) to the ffmpeg command.
+func (e *Encoder) GetVideoContext(ctx context.Context, input, title string) (string, io.ReadCloser, error) {
 	if input == "" {
 		return "", nil, ErrInvalidInput
 	}
 
-	cmdStr, cmd := e.getVideoHandle(input, "-", title)
+	cmdStr, cmd := e.getVideoHandle(ctx, input, "-", title)
 
 	stdoutpipe, err := cmd.StdoutPipe()
 	if err != nil {
@@ -248,26 +269,42 @@ func (e *Encoder) GetVideo(input, title string) (string, io.ReadCloser, error) {
 // SaveVideo saves a video snippet to a file.
 // Input must be an RTSP URL and output must be a file path. It will be overwritten.
 // Returns command used, command output and error or nil.
+// This will automatically create a context with a timeout equal to the time duration requested plus 1 second.
+// If no time duration is requested the context has no timeout.
+// If you want to control the context, use SaveVideoContext().
 func (e *Encoder) SaveVideo(input, output, title string) (string, string, error) {
+	ctx := context.Background()
+
+	if e.config.Time > 0 {
+		var cancel func()
+
+		ctx, cancel = context.WithTimeout(ctx, time.Second*time.Duration(e.config.Time+1))
+		defer cancel()
+	}
+
+	return e.SaveVideoContext(ctx, input, output, title)
+}
+
+// SaveVideoContext saves a video snippet to a file using a provided context.
+// Input must be an RTSP URL and output must be a file path. It will be overwritten.
+// Returns command used, command output and error or nil.
+// Use the context to add a timeout value (max run duration) to the ffmpeg command.
+func (e *Encoder) SaveVideoContext(ctx context.Context, input, output, title string) (string, string, error) {
 	if input == "" {
 		return "", "", ErrInvalidInput
 	} else if output == "" || output == "-" {
 		return "", "", ErrInvalidOutput
 	}
 
-	cmdStr, cmd := e.getVideoHandle(input, output, title)
+	cmdStr, cmd := e.getVideoHandle(ctx, input, output, title)
 	// log.Println(cmdStr) // DEBUG
 
-	var out bytes.Buffer
-	cmd.Stderr, cmd.Stdout = &out, &out
-
-	if err := cmd.Start(); err != nil {
-		return cmdStr, strings.TrimSpace(out.String()), fmt.Errorf("subcommand failed: %w", err)
-	} else if err := cmd.Wait(); err != nil {
-		return cmdStr, strings.TrimSpace(out.String()), fmt.Errorf("subcommand failed: %w", err)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return cmdStr, string(out), fmt.Errorf("subcommand failed: %w", err)
 	}
 
-	return cmdStr, strings.TrimSpace(out.String()), nil
+	return cmdStr, string(out), nil
 }
 
 // fixValues makes sure video request values are sane.

encode_test.go

@@ -68,7 +68,7 @@ func TestSaveVideo(t *testing.T) {
 	assert.True(strings.HasPrefix(cmd, "echo"), "The command does not - but should - begin with the Encoder value.")
 	assert.True(strings.HasSuffix(cmd, fileTemp),
 		"The command does not - but should - end with a dash to indicate output to stdout.")
-	assert.EqualValues(cmd, "echo "+out, "Somehow the wrong value was written")
+	assert.EqualValues(cmd, "echo "+strings.TrimSpace(out), "Somehow the wrong value was written")
 
 	// Make sure audio can be turned on.
 	encode = Get(&Config{FFMPEG: "echo", Audio: true})

go.mod

@@ -1,5 +1,11 @@
 module golift.io/ffmpeg
 
-go 1.15
+go 1.19
 
 require github.com/stretchr/testify v1.8.4
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -1,4 +1,3 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -7,20 +6,16 @@ github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZN
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
-github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
-github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
 github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 github.com/stretchr/testify v1.8.3 h1:RP3t2pwF7cMEbC1dqtB6poj3niw/9gnV4Cjg5oW5gtY=
 github.com/stretchr/testify v1.8.3/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=