# 01 — Using supabase nix Let's clone this repo: ```bash git clone https://github.com/supabase/postgres $HOME/supabase-postgres cd $HOME/supabase-postgres ``` ## Hashes for everyone But how do we build stuff within it? With `nix build`, of course! For example, the following command will, when completed, create a symlink named `result` that points to a path which contains an entire PostgreSQL 15 installation — extensions and all: ``` nix build .#psql_15/bin ``` ``` $ readlink result /nix/store/ybf48481x033649mgdzk5dyaqv9dppzx-postgresql-and-plugins-15.3 ``` ``` $ ls result bin include lib share ``` ``` $ ll result/bin/ total 9928 dr-xr-xr-x 2 root root 4096 Dec 31 1969 ./ dr-xr-xr-x 5 root root 4096 Dec 31 1969 ../ lrwxrwxrwx 1 root root 79 Dec 31 1969 .initdb-wrapped -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/.initdb-wrapped* -r-xr-xr-x 1 root root 9829624 Dec 31 1969 .postgres-wrapped* lrwxrwxrwx 1 root root 73 Dec 31 1969 clusterdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/clusterdb* lrwxrwxrwx 1 root root 72 Dec 31 1969 createdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/createdb* lrwxrwxrwx 1 root root 74 Dec 31 1969 createuser -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/createuser* lrwxrwxrwx 1 root root 70 Dec 31 1969 dropdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/dropdb* lrwxrwxrwx 1 root root 72 Dec 31 1969 dropuser -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/dropuser* lrwxrwxrwx 1 root root 68 Dec 31 1969 ecpg -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/ecpg* lrwxrwxrwx 1 root root 70 Dec 31 1969 initdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/initdb* lrwxrwxrwx 1 root root 72 Dec 31 1969 oid2name -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/oid2name* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_amcheck -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_amcheck* lrwxrwxrwx 1 root root 81 Dec 31 1969 pg_archivecleanup -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_archivecleanup* lrwxrwxrwx 1 root root 77 Dec 31 1969 pg_basebackup -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_basebackup* lrwxrwxrwx 1 root root 76 Dec 31 1969 pg_checksums -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_checksums* -r-xr-xr-x 1 root root 53432 Dec 31 1969 pg_config* lrwxrwxrwx 1 root root 78 Dec 31 1969 pg_controldata -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_controldata* -r-xr-xr-x 1 root root 82712 Dec 31 1969 pg_ctl* lrwxrwxrwx 1 root root 71 Dec 31 1969 pg_dump -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_dump* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_dumpall -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_dumpall* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_isready -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_isready* lrwxrwxrwx 1 root root 77 Dec 31 1969 pg_receivewal -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_receivewal* lrwxrwxrwx 1 root root 78 Dec 31 1969 pg_recvlogical -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_recvlogical* lrwxrwxrwx 1 root root 73 Dec 31 1969 pg_repack -> /nix/store/bi9i5ns4cqxk235qz3srs9p4x1qfxfna-pg_repack-1.4.8/bin/pg_repack* lrwxrwxrwx 1 root root 75 Dec 31 1969 pg_resetwal -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_resetwal* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_restore -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_restore* lrwxrwxrwx 1 root root 73 Dec 31 1969 pg_rewind -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_rewind* lrwxrwxrwx 1 root root 77 Dec 31 1969 pg_test_fsync -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_test_fsync* lrwxrwxrwx 1 root root 78 Dec 31 1969 pg_test_timing -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_test_timing* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_upgrade -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_upgrade* lrwxrwxrwx 1 root root 79 Dec 31 1969 pg_verifybackup -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_verifybackup* lrwxrwxrwx 1 root root 74 Dec 31 1969 pg_waldump -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pg_waldump* lrwxrwxrwx 1 root root 71 Dec 31 1969 pgbench -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/pgbench* lrwxrwxrwx 1 root root 71 Dec 31 1969 pgsql2shp -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgsql2shp* lrwxrwxrwx 1 root root 77 Dec 31 1969 pgsql2shp-3.3.3 -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgsql2shp-3.3.3* lrwxrwxrwx 1 root root 75 Dec 31 1969 pgtopo_export -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgtopo_export* lrwxrwxrwx 1 root root 81 Dec 31 1969 pgtopo_export-3.3.3 -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgtopo_export-3.3.3* lrwxrwxrwx 1 root root 75 Dec 31 1969 pgtopo_import -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgtopo_import* lrwxrwxrwx 1 root root 81 Dec 31 1969 pgtopo_import-3.3.3 -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/pgtopo_import-3.3.3* -r-xr-xr-x 1 root root 286 Dec 31 1969 postgres* lrwxrwxrwx 1 root root 74 Dec 31 1969 postmaster -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/postmaster* lrwxrwxrwx 1 root root 68 Dec 31 1969 psql -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/psql* lrwxrwxrwx 1 root root 74 Dec 31 1969 raster2pgsql -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/raster2pgsql* lrwxrwxrwx 1 root root 80 Dec 31 1969 raster2pgsql-3.3.3 -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/raster2pgsql-3.3.3* lrwxrwxrwx 1 root root 73 Dec 31 1969 reindexdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/reindexdb* lrwxrwxrwx 1 root root 71 Dec 31 1969 shp2pgsql -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/shp2pgsql* lrwxrwxrwx 1 root root 77 Dec 31 1969 shp2pgsql-3.3.3 -> /nix/store/4wwzd3c136g6j7aqva2gyiqgwy784qjv-postgis-3.3.3/bin/shp2pgsql-3.3.3* lrwxrwxrwx 1 root root 72 Dec 31 1969 vacuumdb -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/vacuumdb* lrwxrwxrwx 1 root root 72 Dec 31 1969 vacuumlo -> /nix/store/kdjdxnyhpwpvb11da8s99ylqilspcmzl-postgresql-15.3/bin/vacuumlo* ``` As we can see, these files all point to paths under `/nix/store`. We're actually looking at a "farm" of symlinks to various paths, but collectively they form an entire installation directory we can reuse as much as we want. The path `/nix/store/ybf48481x033649mgdzk5dyaqv9dppzx-postgresql-and-plugins-15.3` ultimately is a cryptographically hashed, unique name for our installation of PostgreSQL with those plugins. This hash includes _everything_ used to build it, so even a single change anywhere to any extension or version would result in a _new_ hash. The ability to refer to a piece of data by its hash, by some notion of _content_, is a very powerful primitive, as we'll see later. ## Build a different version: v16 What if we wanted PostgreSQL 16 and plugins? Just replace `_15` with `_16`: ``` nix build .#psql_16/bin ``` You're done: ``` $ readlink result /nix/store/p7ziflx0000s28bfb213jsghrczknkc4-postgresql-and-plugins-14.8 ``` ## Using `nix develop` `nix develop .` will just drop you in a subshell with tools you need _ready to go instantly_. That's all you need to do! And once that shell goes away, nix installed tools will be removed from your `$PATH` as well. There's an even easier way to do this [that is completely transparent to you, as well](./use-direnv.md).