a script to download ollama models using WGET with hash verification

ollama-pull.sh

#!/bin/bash

die(){
  echo "$1"
  exit 1
}

# Function to verify SHA256 hash of a downloaded file.
verify_hash(){
  local expected="$1"
  local file="$2"
  # Strip the "sha256:" prefix from the expected hash, if present
  expected="${expected#sha256:}"
  echo "[=] Computing hash for: $file"
  if ! computed=$(sha256sum "$file" 2>/dev/null | awk '{print $1}'); then
    die "[x] Failed to compute hash for $file"
  fi
  if [ "$expected" != "$computed" ]; then
    echo "[x] Hash mismatch:"
    echo "[-] expected: $expected"
    die  "[x] computed: $computed"
  else
    echo "[+] Hash verified"
  fi
}

# Check for required commands
command -v jq >/dev/null || die "Need jq"
command -v wget >/dev/null || die "Need wget"

# Check if a model name is provided
if [ -z "$1" ]; then
  die "usage: $0 modelname[:tag] [path-to-save-models]"
fi

# The first argument is the model name with optional tag
model_name="$1"

# The second argument is the path to save the model (optional)
model_dir="${2:-./models}"

# Remove trailing slash from model_dir if it exists
model_dir="${model_dir%/}"

# Parse model name and tag
name=${model_name%%:*}
[[ "$model_name" = *:* ]] && tag="${model_name##*:}" || tag=latest
[[ "$model_name" = */* ]] && base_path="" || base_path="/library"

# Ensure the model directory is valid
if [ ! -d "$model_dir" ]; then
  echo "[=] Directory $model_dir does not exist. Creating it."
  mkdir -p "$model_dir" || die "[x] Couldn't create directory $model_dir"
fi

# Create necessary subdirectories in the model directory
mkdir -p "$model_dir/blobs" || die "Couldn't create blobs directory in $model_dir"
mkdir -p "$model_dir/manifests/registry.ollama.ai/library/$name" || die "Couldn't create manifests directory in $model_dir"

# Define manifest file path (we save it as <tag>)
manifest_file="$model_dir/manifests/registry.ollama.ai/library/$name/$tag"
if [ -e "$manifest_file" ]; then
  die "[x] Manifest file $manifest_file already exists"
fi

# Construct the URL for the manifest
url="https://registry.ollama.ai/v2$base_path/$name/manifests/$tag"
echo "[=] Fetching manifest from: $url"
# Fetch the manifest using wget (quietly outputting to stdout)
manifest=$(wget -qO- "$url") || die "[x] Couldn't fetch manifest"

# Check for errors in the manifest
errors=$(jq -cn "$manifest | .errors")
[ "$errors" = "null" ] || die "$errors"

# Extract config digest from the manifest
config=$(jq -rn "$manifest | .config.digest") || die "[x] No config digest"

# Download the config blob with resume support
echo "[=] Downloading config: $config"
config_file="$model_dir/blobs/${config/:/-}"
wget -q --show-progress --continue --output-document="$config_file" "https://registry.ollama.ai/v2$base_path/$name/blobs/$config" || die "[x] Couldn't fetch config blob"
verify_hash "$config" "$config_file"

# Download each layer listed in the manifest
for layer in $(jq -rn "$manifest | .layers[].digest"); do
  echo "[=] Downloading layer : $layer"
  layer_file="$model_dir/blobs/${layer/:/-}"
  wget -q --show-progress --tries=0 --read-timeout=30 --timeout=30 --waitretry=5 --continue --output-document="$layer_file" "https://registry.ollama.ai/v2$base_path/$name/blobs/$layer" || die "[x] Couldn't fetch layer $layer"
  verify_hash "$layer" "$layer_file"
done

# Write the manifest file
echo -ne "$manifest" > "$manifest_file" || die "[x] Couldn't write manifest"
echo "[+] Download complete."
echo "[+] Files saved in $model_dir"

poweruser@debian:~$ ~/Scripts/ollama-pull.sh granite-embedding:30m /media/poweruser/data/2-ollama-models/
[=] Fetching manifest from: https://registry.ollama.ai/v2/library/granite-embedding/manifests/30m
[=] Downloading config: sha256:b4bff7b70b564130d0b58da27a04a04e97143106fb0185e65a0c855db6999fdf
/media/poweruser/data/2-ollama-model 100%[=====================================================================>]     336  --.-KB/s    in 0s      
[=] Computing hash for: /media/poweruser/data/2-ollama-models/blobs/sha256-b4bff7b70b564130d0b58da27a04a04e97143106fb0185e65a0c855db6999fdf
[+] Hash verified
[=] Downloading layer : sha256:27d24c87a53d110b95abecbff83f966206857a9dc0ba1efd336d08dbd0afc833
/media/poweruser/data/2-ollama-model 100%[=====================================================================>]  59.63M  3.46MB/s    in 17s     
[=] Computing hash for: /media/poweruser/data/2-ollama-models/blobs/sha256-27d24c87a53d110b95abecbff83f966206857a9dc0ba1efd336d08dbd0afc833
[+] Hash verified
[=] Downloading layer : sha256:492069a62c2545ecde9f8cbc5c3d46adadaa3f95c0e1f68aea7ed2cca548484b
/media/poweruser/data/2-ollama-model 100%[=====================================================================>]  11.07K  --.-KB/s    in 0.01s   
[=] Computing hash for: /media/poweruser/data/2-ollama-models/blobs/sha256-492069a62c2545ecde9f8cbc5c3d46adadaa3f95c0e1f68aea7ed2cca548484b
[+] Hash verified
[+] Download complete.
[+] Files saved in /media/poweruser/data/2-ollama-models
poweruser@debian:~$ 

i modified your script to download models to default ollama location to save some work, it works great. thank you very much.