Allow connections via SSH agent

docs/data-sources/file.md

@@ -70,6 +70,7 @@ Optional:
 - **private_key_env_var** (String) The name of the local environment variable containing the private key used to login to the remote host.
 - **private_key_path** (String) The local path to the private key used to login to the remote host.
 - **sudo** (Boolean) Use sudo to gain access to file. Defaults to `false`.
+- **agent** (Booean) Use local SSH agent to login to the remote host. Default to `false`.
 
 
 <a id="nestedatt--result_conn"></a>
@@ -85,5 +86,5 @@ Read-Only:
 - **private_key_path** (String)
 - **sudo** (Boolean)
 - **user** (String)
-
+- **agent** (Booean)
 

docs/index.md

@@ -71,3 +71,4 @@ Optional:
 - **private_key_env_var** (String) The name of the local environment variable containing the private key used to login to the remote host.
 - **private_key_path** (String) The local path to the private key used to login to the remote host.
 - **sudo** (Boolean) Use sudo to gain access to file. Defaults to `false`.
+- **agent** (Booean) Use local SSH agent to login to the remote host. Default to `false`.

internal/provider/connection.go

@@ -3,10 +3,12 @@ package provider
 import (
 	"fmt"
 	"io/ioutil"
+	"net"
 	"os"
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 	"golang.org/x/crypto/ssh"
+	"golang.org/x/crypto/ssh/agent"
 )
 
 var connectionSchemaResource = &schema.Resource{
@@ -56,6 +58,13 @@ var connectionSchemaResource = &schema.Resource{
 			Optional:    true,
 			Description: "The name of the local environment variable containing the private key used to login to the remote host.",
 		},
+		"agent": {
+			Type:        schema.TypeBool,
+			Optional:    true,
+			Default:     false,
+			Description: "Use a local SSH agent to login to the remote host.",
+		},
+
 	},
 }
 
@@ -107,6 +116,15 @@ func ConnectionFromResourceData(d *schema.ResourceData) (string, *ssh.ClientConf
 		clientConfig.Auth = append(clientConfig.Auth, ssh.PublicKeys(signer))
 	}
 
+	enable_agent, ok := d.GetOk("result_conn.0.agent")
+	if ok && enable_agent.(bool) {
+		sshAgent, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK"))
+		if err != nil {
+			return "", nil, fmt.Errorf("couldn't connect to SSH agent: %s", err.Error())
+		}
+		clientConfig.Auth = append(clientConfig.Auth, ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers))
+	}
+
 	host := fmt.Sprintf("%s:%d", d.Get("result_conn.0.host").(string), d.Get("result_conn.0.port").(int))
 	return host, &clientConfig, nil
 }