utern

The “best of best” way to tail AWS CloudWatch Logs from your terminal.

Abstract

Utern allows you to tail log events from multiple log groups and log streams on AWS CloudWatch Logs. Each result is color coded for quicker debugging. Inspired by stern.

The query is a regular expression so the log group name and stream name can easily be filtered and you don't need to specify the exact name. If a stream is deleted it gets removed from tail and if a new stream is added it automatically gets tailed.

When a log group contains multiple log streams, Utern can tail all of them too without having to do this manually for each one. Simply specify the filter to limit what log events to show.

$ utern [options] log-group-query

So Simple!!

The log-group-query is a regular expression so you could provide "web-\w" to tail web-backend and web-frontend log groups but not web-123.

Features

• Multi log groups tailing in parallel
  • Regular expression
• Multi log streams tailing in parallel
  • Regular expression
• Colorful
  • Quicker debugging
• Flexible date and time parser
  • Human friendly formats, i.e. 1h20m to indicate 1 hour and 20 minutes ago
  • A full timestamp 2019-01-02T03:04:05Z (RFC3339)
• Powerful built-in filter
  • https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html
• Fast
  • Written in golang
• Easy installation
  • Pre-built binaries

Installation

From source

$ go get -u github.com/knqyf263/utern

Binary (Including Windows)

Go to the releases page, find the version you want, and download the zip file. Unpack the zip file, and put the binary to somewhere you want (on UNIX-y systems, /usr/local/bin or the like). Make sure it has execution bits turned on.

Mac OS X / Homebrew

You can use homebrew on OS X.

$ brew tap knqyf263/utern
$ brew install knqyf263/utern/utern

If you receive an error (Error: knqyf263/utern/utern 64 already installed) during brew upgrade, try the following command

$ brew unlink utern && brew uninstall utern
($ rm -rf /usr/local/Cellar/utern/64)
$ brew install knqyf263/utern/utern

RedHat, CentOS

Download rpm package from the releases page

$ sudo rpm -ivh https://github.com/knqyf263/utern/releases/download/v0.0.1/utern_0.0.1_Tux_64-bit.rpm

Debian, Ubuntu

Download deb package from the releases page

$ wget https://github.com/knqyf263/utern/releases/download/v0.0.1/utern_0.0.1_Tux_64-bit.deb
$ sudo dpkg -i utern_0.0.1_Tux_64-bit.deb

Examples

Some examples are shown below.

List all log groups

$ aws logs describe-log-groups --query "logGroups[].[logGroupName]" --output text

List all log streams

$ aws logs describe-log-streams --log-group-name log-group-name --query "logStreams[].[logStreamName]" --output text

All log streams

$ utern log-group-query

Filter log groups with regular expressions

$ utern "web-\w"

Filter log streams with regular expressions (--stream, -n)

$ utern --stream log-stream-query log-group-query

Filter log streams with a prefix of log stream name (--stream-prefix, -p)

If the log group has many log streams, --stream-prefix will be faster than --stream.

$ utern --stream-prefix log-stream-prefix log-group-query

Filter log streams with a prefix and regular expressions

$ utern -p log-stream-prefix -n log-stream-query log-group-query

Logs after 1 hour ago (--since, -s)

$ utern --since 1h log-group-query

Logs after 2019-01-02 03:04:05 UTC

RFC3339

$ utern --since 2019-01-02T03:04:05Z log-group-query

Logs from 10 minutes ago to 5 minutes ago

$ utern --since 10m --end 5m log-group-query

Usage

NAME:
   utern - Multi group and stream log tailing for AWS CloudWatch Logs

USAGE:
   utern [global options] command [command options] [arguments...]

VERSION:
   0.1.1

COMMANDS:
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --stream value, -n value         Log stream name (regular expression).
                                    Displays all if omitted. If the option
                                    "since" is set to recent time, this option
                                    usually makes it faster than the option
                                    "stream-prefix"
   --stream-prefix value, -p value  Log stream name prefix. If a log group
                                    contains many log streams, this option makes
                                    it faster.
   --since value, -s value          Return logs newer than a relative duration
                                    like 52, 2m, or 3h. (default: "5m")
   --end value, -e value            Return logs older than a relative duration
                                    like 0, 2m, or 3h.
   --profile value                  Specify an AWS profile.
   --code value                     Specify MFA token code directly
                                    (if applicable), instead of using stdin.
   --region value, -r value         Specify an AWS region.
   --filter value                   The filter pattern to use. For more
                                    information, see https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html.
   --timestamps                     Print timestamps
   --event-id                       Print event ID
   --no-log-group                   Suppress display of log group name
   --no-log-stream                  Suppress display of log stream name
   --max-length value               Maximum log message length (default: 0)
   --color                          Force color output even if not a tty
   --help, -h                       show help
   --version, -v                    print the version

Contribute

1. fork a repository: github.com/knqyf263/utern to github.com/you/repo
2. get original code: go get github.com/knqyf263/utern
3. work on original code
4. add remote to your repo: git remote add myfork https://github.com/you/repo.git
5. push your changes: git push myfork
6. create a new Pull Request

• see GitHub and Go: forking, pull requests, and go-getting

License

MIT

Author

Teppei Fukuda