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docker/dFile.md

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+# Keywords
+
+## FROM (module)
+* gives instructions about the base platform to use (node, fedora, etc)
+- `FROM node:20`
+
+
+## WORKDIR (path)
+* like when you `cd` into a directory
+* makes sure any commands executed will be in this directory
+- `WORKDIR /app`
+
+
+## COPY (src) (dest)
+* copies files from `src` to `dest`
+* I THINK it's like a symbolic link? Maybe?
+- `COPY package*.json ./`
+
+*Note: you can get docker to ignore files by creating a `.dockerignore` file*
+
+
+## RUN (commands)
+* like running a command in the terminal!
+* `RUN npm install`
+
+
+## ENV ((varName=varVal) (varName2=varVal2) ...)
+* sets env vars (like doing it from the command line)
+- `ENV PORT=3000`
+
+
+## EXPOSE (PORT)
+* this will expose a port to the network
+- `EXPOSE 3000`
+
+
+## CMD (args[])
+* only ONE per dockerfile
+* will tell the container how to run the application
+* same as nodejs `spawn` args
+- `CMD ["npm", "start"]`
+
+
+# Notes
+every step/instruction in docker is it's own layer
+- docker attempts to cache layers if nothing is changes
+- this means we want to install dependancies first so they aren't re-installed every time (i.e. are cached)