clic is a small program that adds very dumb caching support for command line tools.
It can be useful when the output of a slow command needs to be used several times. The cache is currently backed by a sqlite3 database.
% clic --help # Display usage & options
Usage:
clic -h|-help|--help
clic [-db database] -init
clic [options...] [--] COMMAND [COMMAND_ARGS...]
Options:
-clean
clean up old entries (wrt TTL)
-config string
config file (optional)
-db string
sqlite3 DB path (default "clic.sqlite3")
-get
get cached result
-init
create/initialize database
-ttl duration
cache TTL (default 2m0s)
-verbose
log verbose information
All options can be provided through an environment variable (e.g. CLIC_DB) or a plaintext configuration file (option value).
The database must be initialized (-init creates the DB with the cache table, or clears the table if it already exists) before the cache can be used:
% export CLIC_DB="$HOME/clic.db"
% clic -init
You can use the -verbose flag to see what's going on:
% clic -verbose -init
2021/08/04 22:50:29 Initializing DB file [/home/mikael/clic.db]...
A simple example with date:
% clic -verbose date +%H:%M:%S
2021/08/04 23:04:41 Using cache DB file [/home/mikael/clic.db]
2021/08/04 23:04:41 No cached result
2021/08/04 23:04:41 Running external command...
2021/08/04 23:04:41 Storing item in cache DB...
23:04:41
% sleep 2; clic -ttl 4s -- date +%H:%M:%S # cache still valid, not running date
23:04:41
% sleep 2; clic -ttl 4s -- date +%H:%M:%S # cache entry older than 4s
23:04:45
% sleep 2; clic -ttl 4s -- date +%H:%M:%S # cache still valid...
23:04:45
Reuse a slow Kubernetes cluster query:
% clic -- kubectl get pods --all-namespaces -o wide | grep node-7
% clic -- kubectl get pods --all-namespaces -o wide | grep node-8
Same, but considering that all entries older than 30 seconds can't be used:
% clic -ttl 30s -- kubectl get pods --all-namespaces -o wide | grep node-8
Cache a slow find query result:
% time clic sudo find /usr -name "*clic*" > /dev/null
clic sudo find /usr -name "*clic*" > /dev/null 0.35s user 0.32s system 3% cpu 18.153 total
% time clic sudo find /usr -name "*clic*" > /dev/null
clic sudo find /usr -name "*clic*" > /dev/null 0.00s user 0.00s system 109% cpu 0.008 total
Drop all cache entries older than 1 hour:
% clic -clean -ttl 1h
The usual process for Golang builds should work fine:
go install github.com/McKael/clic@latest
- The standard error of the called process is discarded.
% clic ls /lost+found
2021/08/04 23:25:15 Error: command failed: exit status 2
A workaround could be (in some cases) to use a shell redirection:
% clic bash -c "ls /lost+found 2>&1"
ls: cannot open directory '/lost+found': Permission denied
2021/08/04 23:25:24 Error: command failed: exit status 2
- When the command fails, the standard output is still displayed but the cache is not updated (so the command should be run again next time).