Add support for image_copy_tmp_dir

Allow users to set the default location for the temporary files used
during image pulls and pushes.

Defaults to /var/tmp;

Overridden via "TMPDIR" environment variable.

Allow special flag "storage" to indicate the the storage should use
the tmp directory in containers/storage/tmp.

Needed to fix: containers/podman#11107

Signed-off-by: Daniel J Walsh <[email protected]>

docs/containers.conf.5.md

@@ -491,6 +491,12 @@ The list of OCI runtimes that support running containers with KVM separation.
 
 The list of OCI runtimes that support running containers without CGroups.
 
+**image_copy_tmp_dir**="/var/tmp"
+
+Default location for storing temporary container image content.  Can be
+overridden with the TMPDIR environment variable.  If you specify "storage", then
+the location of the container/storage tmp directory will be used.
+
 **static_dir**="/var/lib/containers/storage/libpod"
 
 Directory for persistent libpod files (database, etc).

pkg/config/config.go

@@ -234,6 +234,8 @@ type EngineConfig struct {
 	// EventsLogger determines where events should be logged.
 	EventsLogger string `toml:"events_logger,omitempty"`
 
+	// graphRoot internal stores the location of the graphroot
+	graphRoot string
 	// configuration files. When the same filename is present in in
 	// multiple directories, the file in the directory listed last in
 	// this slice takes precedence.
@@ -380,6 +382,12 @@ type EngineConfig struct {
 	// before sending kill signal.
 	StopTimeout uint `toml:"stop_timeout,omitempty"`
 
+	// ImageCopyTmpDir is the default location for storing temporary
+	// container image content,  Can be overridden with the TMPDIR
+	// environment variable.  If you specify "storage", then the
+	// location of the container/storage tmp directory will be used.
+	ImageCopyTmpDir string `toml:"image_copy_tmp_dir,omitempty"`
+
 	// TmpDir is the path to a temporary directory to store per-boot container
 	// files. Must be stored in a tmpfs.
 	TmpDir string `toml:"tmp_dir,omitempty"`

pkg/config/config_test.go

@@ -28,6 +28,7 @@ var _ = Describe("Config", func() {
 			gomega.Expect(err).To(gomega.BeNil())
 			gomega.Expect(defaultConfig.Containers.ApparmorProfile).To(gomega.Equal(apparmor.Profile))
 			gomega.Expect(defaultConfig.Containers.PidsLimit).To(gomega.BeEquivalentTo(2048))
+			gomega.Expect(defaultConfig.ImageCopyTmpDir()).To(gomega.BeEquivalentTo("/var/tmp"))
 		})
 
 		It("should succeed with devices", func() {
@@ -107,6 +108,31 @@ var _ = Describe("Config", func() {
 		})
 	})
 
+	Describe("readStorageTmp", func() {
+		It("test image_copy_tmp_dir='storage'", func() {
+			// Reload from new configuration file
+			testFile := "testdata/temp.conf"
+			content := `[engine]
+image_copy_tmp_dir="storage"`
+			err := ioutil.WriteFile(testFile, []byte(content), os.ModePerm)
+			// Then
+			gomega.Expect(err).To(gomega.BeNil())
+			defer os.Remove(testFile)
+
+			config, _ := NewConfig(testFile)
+			gomega.Expect(config.ImageCopyTmpDir()).To(gomega.ContainSubstring("containers/storage/tmp"))
+			// Given we do
+			oldTMPDIR, set := os.LookupEnv("TMPDIR")
+			os.Setenv("TMPDIR", "/var/tmp/foobar")
+			gomega.Expect(config.ImageCopyTmpDir()).To(gomega.BeEquivalentTo("/var/tmp/foobar"))
+			if set {
+				os.Setenv("TMPDIR", oldTMPDIR)
+			} else {
+				os.Unsetenv("TMPDIR")
+			}
+		})
+	})
+
 	Describe("readConfigFromFile", func() {
 		It("should succeed with default config", func() {
 			// Given
@@ -327,6 +353,7 @@ var _ = Describe("Config", func() {
 			gomega.Expect(config.Containers.LogSizeMax).To(gomega.Equal(int64(100000)))
 			gomega.Expect(config.Engine.ImageParallelCopies).To(gomega.Equal(uint(10)))
 			gomega.Expect(config.Engine.ImageDefaultFormat).To(gomega.Equal("v2s2"))
+			gomega.Expect(config.ImageCopyTmpDir()).To(gomega.BeEquivalentTo("/tmp/foobar"))
 		})
 
 		It("should fail with invalid value", func() {

pkg/config/containers.conf

@@ -452,6 +452,11 @@ default_sysctls = [
 #
 #runtime_supports_nocgroups = ["crun"]
 
+# Default location for storing temporary container image content,  Can be overridden with the TMPDIR environment
+# variable.  If you specify "storage", then the location of the
+# container/storage tmp directory will be used.
+# image_copy_tmp_dir="/var/tmp"
+
 # Directory for persistent engine files (database, etc)
 # By default, this will be configured relative to where the containers/storage
 # stores containers

pkg/config/default.go

@@ -244,6 +244,8 @@ func defaultConfigFromMemory() (*EngineConfig, error) {
 		logrus.Warnf("Storage configuration is unset - using hardcoded default graph root %q", _defaultGraphRoot)
 		storeOpts.GraphRoot = _defaultGraphRoot
 	}
+	c.graphRoot = storeOpts.GraphRoot
+	c.ImageCopyTmpDir = "/var/tmp"
 	c.StaticDir = filepath.Join(storeOpts.GraphRoot, "libpod")
 	c.VolumePath = filepath.Join(storeOpts.GraphRoot, "volumes")
 
@@ -562,3 +564,14 @@ func (c *Config) RootlessNetworking() string {
 func (c *Config) MachineImage() string {
 	return c.Engine.MachineImage
 }
+
+// ImageCopyTmpDir default storage tmpdir
+func (c *Config) ImageCopyTmpDir() string {
+	if path, found := os.LookupEnv("TMPDIR"); found {
+		return path
+	}
+	if c.Engine.ImageCopyTmpDir == "storage" {
+		return filepath.Join(c.Engine.graphRoot, "tmp")
+	}
+	return c.Engine.ImageCopyTmpDir
+}

pkg/config/testdata/containers_default.conf

@@ -119,6 +119,9 @@ conmon_env_vars = [
 		"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 ]
 
+image_copy_tmp_dir="storage"
+
+
 # Paths to look for the Conmon container manager binary
 conmon_path = [
 	    "/usr/libexec/podman/conmon",

pkg/config/testdata/containers_override.conf

@@ -8,6 +8,7 @@ log_size_max = 100000
 [engine]
 image_parallel_copies=10
 image_default_format="v2s2"
+image_copy_tmp_dir="/tmp/foobar"
 
 [secrets]
 driver = "pass"