How to make HTTP requests from a minimal Docker container using bash /dev/tcp
By
Marek Šuppa
18d ago· 3 min readen
Summary
A practical guide on making HTTP requests from minimal Docker containers that lack curl or wget. The solution uses bash's built-in /dev/tcp feature to open a TCP socket and manually write an HTTP/1.1 request, enabling health checks and connectivity testing between containers on a shared Docker network without installing additional tools.
Source
Hacker NewsHow to make HTTP requests from a minimal Docker container using bash /dev/tcpmareksuppa.comKey quotes
· 3 pulledbash can speak HTTP by itself bash can open a TCP socket, and you can write a small HTTP request to it by hand.
Opening a connection to a host and port and writing the request needs nothing beyond the shell that's already there.
The obvious move is curl http://service:8642/health. But this app image was stripped right down, with no curl or wget and nothing else around that I could use to open a socket.
Minimal container images often ship without curl, wget, or any HTTP client at all. Bash can open a TCP socket through /dev/tcp, which is enough to write a tiny HTTP/1.1 request by hand for quick checks.
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