Add support for --connection

* override --url and/or --identity fields from containers.conf
* --connection flag has higher precedence than ActiveService from
containers.conf. Which is set via podman system connection default
* Add newline to error message printed on stderr
* Added --connection to bash completion and documentation
* Updated bindings to query server in case of no path or /

Closes #jira-991
Fixes #7276

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
Signed-off-by: Jhon Honce <jhonce@redhat.com>

Squashed commits to work around CI issue

cmd/podman/early_init_linux.go

@@ -32,7 +32,7 @@ func setUMask() {
 
 func earlyInitHook() {
 	if err := setRLimits(); err != nil {
-		fmt.Fprint(os.Stderr, "Failed to set rlimits: "+err.Error())
+		fmt.Fprintf(os.Stderr, "Failed to set rlimits: %s\n", err.Error())
 	}
 
 	setUMask()

cmd/podman/root.go

@@ -111,6 +111,30 @@ func persistentPreRunE(cmd *cobra.Command, args []string) error {
 
 	cfg := registry.PodmanConfig()
 
+	// --connection is not as "special" as --remote so we can wait and process it here
+	var connErr error
+	conn := cmd.Root().LocalFlags().Lookup("connection")
+	if conn != nil && conn.Changed {
+		cfg.Engine.ActiveService = conn.Value.String()
+
+		var err error
+		cfg.URI, cfg.Identity, err = cfg.ActiveDestination()
+		if err != nil {
+			connErr = errors.Wrap(err, "failed to resolve active destination")
+		}
+
+		if err := cmd.Root().LocalFlags().Set("url", cfg.URI); err != nil {
+			connErr = errors.Wrap(err, "failed to override --url flag")
+		}
+
+		if err := cmd.Root().LocalFlags().Set("identity", cfg.Identity); err != nil {
+			connErr = errors.Wrap(err, "failed to override --identity flag")
+		}
+	}
+	if connErr != nil {
+		return connErr
+	}
+
 	// Prep the engines
 	if _, err := registry.NewImageEngine(cmd, args); err != nil {
 		return err
@@ -226,10 +250,11 @@ func loggingHook() {
 
 func rootFlags(cmd *cobra.Command, opts *entities.PodmanConfig) {
 	cfg := opts.Config
-	uri, ident := resolveDestination()
+	srv, uri, ident := resolveDestination()
 
 	lFlags := cmd.Flags()
 	lFlags.BoolVarP(&opts.Remote, "remote", "r", false, "Access remote Podman service (default false)")
+	lFlags.StringVarP(&opts.Engine.ActiveService, "connection", "c", srv, "Connection to use for remote Podman service")
 	lFlags.StringVar(&opts.URI, "url", uri, "URL to access Podman service (CONTAINER_HOST)")
 	lFlags.StringVar(&opts.Identity, "identity", ident, "path to SSH identity file, (CONTAINER_SSHKEY)")
 
@@ -279,24 +304,24 @@ func rootFlags(cmd *cobra.Command, opts *entities.PodmanConfig) {
 	}
 }
 
-func resolveDestination() (string, string) {
+func resolveDestination() (string, string, string) {
 	if uri, found := os.LookupEnv("CONTAINER_HOST"); found {
 		var ident string
 		if v, found := os.LookupEnv("CONTAINER_SSHKEY"); found {
 			ident = v
 		}
-		return uri, ident
+		return "", uri, ident
 	}
 
 	cfg, err := config.ReadCustomConfig()
 	if err != nil {
 		logrus.Warning(errors.Wrap(err, "unable to read local containers.conf"))
-		return registry.DefaultAPIAddress(), ""
+		return "", registry.DefaultAPIAddress(), ""
 	}
 
 	uri, ident, err := cfg.ActiveDestination()
 	if err != nil {
-		return registry.DefaultAPIAddress(), ""
+		return "", registry.DefaultAPIAddress(), ""
 	}
-	return uri, ident
+	return cfg.Engine.ActiveService, uri, ident
 }

cmd/podman/system/connection/add.go

@@ -95,7 +95,7 @@ func add(cmd *cobra.Command, args []string) error {
 		uri.Host = net.JoinHostPort(uri.Hostname(), cmd.Flag("port").DefValue)
 	}
 
-	if uri.Path == "" {
+	if uri.Path == "" || uri.Path == "/" {
 		if uri.Path, err = getUDS(cmd, uri); err != nil {
 			return errors.Wrapf(err, "failed to connect to  %q", uri.String())
 		}

completions/bash/podman

@@ -3602,22 +3602,32 @@ _podman_volume() {
 
 _podman_podman() {
      local options_with_args="
-	   --config -c
+	   --cni-config-dir
+	   --conmon
+	   --connection -c
+	   --events-backend
+	   --hooks-dir
+	   --identity
+	   --log-level
+	   --namespace
+	   --network-cmd-path
 	   --root
 	   --runroot
 	   --storage-driver
 	   --storage-opt
-	   --log-level
-	   --namespace
-    "
+	   --tmpdir
+	   --runtime
+	   --url
+     "
      local boolean_options="
 	   --help
-	   -h
-	   --version
-	   -v
 	   --syslog
+	   --version
+	   -h
+	   -r, --remote
+	   -v
      "
-     commands="
+    commands="
     attach
     auto-update
     build

docs/source/markdown/podman-remote.1.md

@@ -23,7 +23,7 @@ Podman-remote provides a local client interacting with a Podman backend node thr
 
 ## GLOBAL OPTIONS
 
-**--connection**=*name*
+**--connection**=*name*, **-c**
 
 Remote connection name
 

docs/source/markdown/podman.1.md

@@ -31,6 +31,9 @@ Note: CGroup manager is not supported in rootless mode when using CGroups Versio
 **--cni-config-dir**
 Path of the configuration directory for CNI networks.  (Default: `/etc/cni/net.d`)
 
+**--connection**, **-c**
+Connection to use for remote podman (Default connection is configured in `containers.conf`)
+
 **--conmon**
 Path of the conmon binary (Default path is configured in `containers.conf`)