How to check if libpcap installed in Alphine docker container

Question

I installed libpcap in my container using below docker file using docker file below. How do I make sure it was installed and working as expected?

I tried below with the hope to see libpcap

D:\work >docker exec -u 0 -it containerId sh

/app # cd /etc/apk

/etc/apk # cat repositories

http://dl-cdn.alpinelinux.org/alpine/v3.8/main

http://dl-cdn.alpinelinux.org/alpine/v3.8/community

/etc/apk # 

Below is my docker file

FROM mcr.microsoft.com/dotnet/core/sdk:2.2-alpine AS build

# Install packages
RUN apk update
RUN apk -U --no-cache add libpcap

Running the apk info command has below output

WARNING: Ignoring APKINDEX.adfa7ceb.tar.gz: No such file or directory

WARNING: Ignoring APKINDEX.efaa1f73.tar.gz: No such file or directory

musl

busybox

alpine-baselayout

alpine-keys

libressl2.7-libcrypto

libressl2.7-libssl

libressl2.7-libtls

ssl_client

zlib

apk-tools

scanelf

musl-utils

libc-utils

ca-certificates

krb5-conf

libcom_err

keyutils-libs

libverto

krb5-libs

libgcc

libintl

libcrypto1.0

libssl1.0

libstdc++

userspace-rcu

lttng-ust

tzdata

Answer 1

Run docker exec command and try this

$ apk info

This will list all the installed packages in alpine.

I can see libcap in the output.

If you still can't see the package. Make sure you have run apk update before installing libcap