updated readme

README.md

@@ -1,64 +1,72 @@
 # AWS Commander
 
-A tool used for running bash scripts on AWS EC2 instances, leveraging AWS Systems Manager > Run Command feature.   
-User can load a bash script or define a single command, that will execute on all instances with defined instance ID.
+A tool used for easier automation of the AWS EC2 instances, leveraging AWS Systems Manager - Run Command feature.   
+Supported scripts:
+* One-liner bash command
+* Bash script loaded from a local filesystem
+* Ansible playbook loaded from a local filesystem
+
+The command/script/playbook will run across all EC2 instances simultaneously.     
+EC2 instances, for now, can be selected only by their IDs. Support for selection by tags will be 
+added in future versions.
+
 
 ## Prerequisites
 
-* The **AmazonSSMManagedInstanceCore** must be placed on all instances that need to be managed via this tool.    
-* AWS API credentials defined in *aws credentials* file or as environment variables
+* The **AmazonSSMManagedInstanceCore** IAM role, attached on all EC2 instances.    
+* Authenticated AWS CLI session 
 
 ## Usage
 
 ### AWS credentials
-AWS credentials can be pulled from environment variables or from aws credentials file.   
-To define a which profile from credentials file should be used, set `aws-profile` flag. By default, it is set to `default`.   
-Environment variables with credentials that can be set:
-* `AWS_ACCESS_KEY_ID` - the aws access key id
-* `AWS_SECRET_ACCESS_KEY` - the access key secret
-* `AWS_SESSION_TOKEN` - the session token (optional)
-
+AWS access must be authenticated via `aws cli`.
 
 ### General Parameters
-* `aws-profile` - AWS profile as defined in *aws credentials* file. Default: `default`
-* `aws-zone` - AWS zone in which EC2 instances reside. Default: `eu-central-1`
-* `instances` - instance IDs, separated by comma (,). This is a mandatory flag.
-* `log-level` - the level of logging output (info, debug, error). Default: `info`
-* `output` - a file name to write the output result of a command/script. Default: `console output`
-* `mode` - switch between modes - Bash script or Ansible playbook. Default: `bash`
+* `log-level` - the level of logging output (`info`, `debug`, `error`). Default: `info`
+* `mode` - commands running mode (`bash`, `ansible`) Default: `bash`
+* `profile` - AWS profile as defined in *aws credentials* file.
+* `region` - AWS region in which EC2 instances reside.
+* `ids` - instance IDs, separated by comma (`,`). This is a mandatory flag.
+* `max-wait` - maximum wait time in seconds to run the command Default: `30`
+* `max-exec` - maximum wait time in seconds to get command result Default: `300`
 
 ### Running Bash scripts
 * `cmd` - one-liner bash command that will be executed on EC2 instances.
 * `script` - the location of bash script file that will run on EC2 instances.
-* `mode` - for running bash scripts `mode` can be omitted as the default value is `bash`
-
-If both `cmd` and `script` flags are defined, `script` will take precedence, and `cmd` will be disregarded.
+* `mode` - for running Bash script or oneliner `mode` can be omitted or set to `bash`
 
 #### Example
 
 ```bash
+# AWS authentication
+aws sso login --profile test-account
+
+# oneliner
 aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -cmd "cd /tmp && ls -lah" -aws-profile test-account
+
+# or bash script
+aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -script ./script.sh -aws-profile test-account
 ```
 
 ### Running Ansible Playbook
 * `playbook` - the location of Ansible playbook that will be executed on EC2 instances.
+* `ansible-url` - the URL locaction of the Ansible playbook
+* `extra-vars` - comma delimited, key value pairs of Ansible variables
 * `dryrun` - when set to true, Ansible playbook will run and the output will be shown, but 
-  no data will be changed. 
+  no data will be changed. Default: `false`
 * `mode` - for running Ansible playbook `mode` must be set to `ansible`
 
-#### Ansible prerequisites
-Every EC2 instance, that should run Ansible playbook, must have Ansible already installed.   
-If Ansible is not installed, the deployment will fail.    
-You can use `bash` mode to simply install Ansible from your OS package manager before running the playbook.
-
 #### Example
 ```bash
-## if Ansible is not installed on host - install Ansible
-aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -cmd "sudo apt install -y ansible" -aws-profile test-account -aws-zone us-west-2
-## run playbook
-aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -mode ansible -playbook scripts/nodes-restart.yaml -aws-profile test-account -aws-zone us-west-2
+# AWS authentication
+aws sso login
+
+# run local playbook
+aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -mode ansible -playbook scripts/init.yaml -extra-vars foo=bar,faz=baz
+
+# or from url
+aws-commander -instances i-0bf9c273c67f684a0,i-011c9b3e3607a63b5,i-0e53e37f7b34517f5,i-0f02ca10faf8f349e -mode ansible -ansible-url https://example.com/init.yaml -extra-vars foo=bar,faz=baz
 ```
 
 #### Missing features
-Currently, running the Ansible playbook from a remote location via URL / S3 is not supported.    
-It will be supported in the future release.
+* Select EC2 instances using instance tags

conf/conf.go

@@ -103,7 +103,7 @@ func (c *Config) processFlags() {
 	flag.Int64Var(&c.CommandExecMaxWait, "max-exec", c.CommandExecMaxWait,
 		"maximum command execution time in seconds",
 	)
-	flag.BoolVar(&c.AnsibleDryRun, "dry-run", c.AnsibleDryRun,
+	flag.BoolVar(&c.AnsibleDryRun, "dryrun", c.AnsibleDryRun,
 		"run ansible in dry-run mode",
 	)
 	flag.StringVar(&c.AnsibleExtraVars, "extra-vars", c.AnsibleExtraVars,