26. Command Output Tags

Commands can print tags to stdout to communicate with Cog. To use one, print it to STDOUT at the beginning of a newline before returning your actual response. If you’re not returning JSON output (by using the JSON tag), you may intersperse tags in along with lines of output if necessary.

26.1. Examples

Output from a command that includes a debug statement, template selection, and JSON response. The debug statement will be printed in the logs of the Relay it ran on, while the JSON output will be rendered in template specified and sent to chat as shown below.

Output from command:

COGCMD_DEBUG: Requst took 53ms to complete
COG_TEMPLATE: instances
JSON
[
  {
    "instance_id": "i-1984f3",
    "instance_type: "t2.micro"
  },
  {
    "instance_id": "i-2a7b11",
    "instance_type: "t2.small"
  }
]

Relay logs:

DEBU[2016-12-06T11:10:14-05:00] (P: 2b113f571dc14419870cffe5d5064e69 C: ec2:instance-list) Request took 53ms to complete

JSON response passed to the instances template:

[
  {
    "instance_id": "i-1984f3",
    "instance_type: "t2.micro"
  },
  {
    "instance_id": "i-2a7b11",
    "instance_type: "t2.small"
  }
]

Output from a command in freeform text which also includes two info statements and also uses a template. The info statement will be printed in the logs of the Relay it ran on, while the text output will be rendered in the template specified and sent to chat. Even though tags were interspersed in the text output, each line that does not start with a tag will be accumulated in an array in the order they were printed. That array will then be included in a JSON object as the value of the body attribute. This JSON can then be used to render a template if provided.

Output from command:

INSTANCE_ID  INSTANCE_TYPE
COGCMD_INFO: 2 instances returned
i-1984f3     t2.micro
i-2a7b11     t2.small
COG_TEMPLATE: monospace

Relay logs:

INFO[2016-12-06T11:10:14-05:00] (P: 2b113f571dc14419870cffe5d5064e69 C: ec2:instance-list) 2 instances returned

JSON response passed to the monospace template:

[
  {
    "body": [
      "INSTANCE_ID  INSTANCE_TYPE",
      "i-1984f3     t2.micro",
      "i-2a7b11     t2.small"
    ]
  }
]

26.2. Tags

COGCMD_ACTION
Currently only used to abort a command by printing COGCMD_ACTION: abort. Aborting a command is different from returning a non-zero exit code. When a command is aborted, the pipeline will stop executing and anything printed to stdout will be returned verbatim as a response in chat. The error template will not be rendered. This is mostly useful for providing concise error messages, such as validation errors, while non-zero exit codes are better suited for unexpected error conditions.
COG_TEMPLATE
Renders the response with the template provided. For example, if your bundle includes a template named “instance-list” you would output COG_TEMPLATE: instance-list before outputting your response. If not used with JSON output expect the raw text output from your command to be available in the $body attribute of the first item of $results in the template.
JSON
Parses the following response as JSON. Must be printed on a new line, by itself, directly before your command’s output. If not provided all non-tag output is assumed to be raw text. Anything output after this tag will be parsed as JSON, so you must not include any other tags after this one.
COGCMD_DEBUG
Prints a log message to Relay with the log level set to DEBUG.
COGCMD_INFO
Prints a log message to Relay with the log level set to INFO.
COGCMD_WARN
Prints a log message to Relay with the log level set to WARN.
COGCMD_ERR; COGCMD_ERROR
Prints a log message to Relay with the log level set to ERROR.