terraform/internal/depsfile/locks.go

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package depsfile
import (
"fmt"
"sort"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/internal/getproviders"
)
// Locks is the top-level type representing the information retained in a
// dependency lock file.
//
// Locks and the other types used within it are mutable via various setter
// methods, but they are not safe for concurrent modifications, so it's the
// caller's responsibility to prevent concurrent writes and writes concurrent
// with reads.
type Locks struct {
providers map[addrs.Provider]*ProviderLock
// TODO: In future we'll also have module locks, but the design of that
// still needs some more work and we're deferring that to get the
// provider locking capability out sooner, because it's more common to
// directly depend on providers maintained outside your organization than
// modules maintained outside your organization.
// sources is a copy of the map of source buffers produced by the HCL
// parser during loading, which we retain only so that the caller can
// use it to produce source code snippets in error messages.
sources map[string][]byte
}
// NewLocks constructs and returns a new Locks object that initially contains
// no locks at all.
func NewLocks() *Locks {
return &Locks{
providers: make(map[addrs.Provider]*ProviderLock),
// no "sources" here, because that's only for locks objects loaded
// from files.
}
}
// Provider returns the stored lock for the given provider, or nil if that
// provider currently has no lock.
func (l *Locks) Provider(addr addrs.Provider) *ProviderLock {
return l.providers[addr]
}
// AllProviders returns a map describing all of the provider locks in the
// receiver.
func (l *Locks) AllProviders() map[addrs.Provider]*ProviderLock {
// We return a copy of our internal map so that future calls to
// SetProvider won't modify the map we're returning, or vice-versa.
ret := make(map[addrs.Provider]*ProviderLock, len(l.providers))
for k, v := range l.providers {
ret[k] = v
}
return ret
}
// SetProvider creates a new lock or replaces the existing lock for the given
// provider.
//
// SetProvider returns the newly-created provider lock object, which
// invalidates any ProviderLock object previously returned from Provider or
// SetProvider for the given provider address.
//
// The ownership of the backing array for the slice of hashes passes to this
// function, and so the caller must not read or write that backing array after
// calling SetProvider.
//
// Only lockable providers can be passed to this method. If you pass a
// non-lockable provider address then this function will panic. Use
// function ProviderIsLockable to determine whether a particular provider
// should participate in the version locking mechanism.
func (l *Locks) SetProvider(addr addrs.Provider, version getproviders.Version, constraints getproviders.VersionConstraints, hashes []getproviders.Hash) *ProviderLock {
if !ProviderIsLockable(addr) {
panic(fmt.Sprintf("Locks.SetProvider with non-lockable provider %s", addr))
}
new := NewProviderLock(addr, version, constraints, hashes)
l.providers[new.addr] = new
return new
}
// NewProviderLock creates a new ProviderLock object that isn't associated
// with any Locks object.
//
// This is here primarily for testing. Most callers should use Locks.SetProvider
// to construct a new provider lock and insert it into a Locks object at the
// same time.
//
// The ownership of the backing array for the slice of hashes passes to this
// function, and so the caller must not read or write that backing array after
// calling NewProviderLock.
//
// Only lockable providers can be passed to this method. If you pass a
// non-lockable provider address then this function will panic. Use
// function ProviderIsLockable to determine whether a particular provider
// should participate in the version locking mechanism.
func NewProviderLock(addr addrs.Provider, version getproviders.Version, constraints getproviders.VersionConstraints, hashes []getproviders.Hash) *ProviderLock {
if !ProviderIsLockable(addr) {
panic(fmt.Sprintf("Locks.NewProviderLock with non-lockable provider %s", addr))
}
// Normalize the hashes into lexical order so that we can do straightforward
// equality tests between different locks for the same provider. The
// hashes are logically a set, so the given order is insignificant.
sort.Slice(hashes, func(i, j int) bool {
return string(hashes[i]) < string(hashes[j])
})
// This is a slightly-tricky in-place deduping to avoid unnecessarily
// allocating a new array in the common case where there are no duplicates:
// we iterate over "hashes" at the same time as appending to another slice
// with the same backing array, relying on the fact that deduping can only
// _skip_ elements from the input, and will never generate additional ones
// that would cause the writer to get ahead of the reader. This also
// assumes that we already sorted the items, which means that any duplicates
// will be consecutive in the sequence.
dedupeHashes := hashes[:0]
prevHash := getproviders.NilHash
for _, hash := range hashes {
if hash != prevHash {
dedupeHashes = append(dedupeHashes, hash)
prevHash = hash
}
}
return &ProviderLock{
addr: addr,
version: version,
versionConstraints: constraints,
hashes: dedupeHashes,
}
}
// ProviderIsLockable returns true if the given provider is eligible for
// version locking.
//
// Currently, all providers except builtin and legacy providers are eligible
// for locking.
func ProviderIsLockable(addr addrs.Provider) bool {
return !(addr.IsBuiltIn() || addr.IsLegacy())
}
// Sources returns the source code of the file the receiver was generated from,
// or an empty map if the receiver wasn't generated from a file.
//
// This return type matches the one expected by HCL diagnostics printers to
// produce source code snapshots, which is the only intended use for this
// method.
func (l *Locks) Sources() map[string][]byte {
return l.sources
}
// Equal returns true if the given Locks represents the same information as
// the receiver.
//
// Equal explicitly _does not_ consider the equality of version constraints
// in the saved locks, because those are saved only as hints to help the UI
// explain what's changed between runs, and are never used as part of
// dependency installation decisions.
func (l *Locks) Equal(other *Locks) bool {
if len(l.providers) != len(other.providers) {
return false
}
for addr, thisLock := range l.providers {
otherLock, ok := other.providers[addr]
if !ok {
return false
}
if thisLock.addr != otherLock.addr {
// It'd be weird to get here because we already looked these up
// by address above.
return false
}
if thisLock.version != otherLock.version {
// Equality rather than "Version.Same" because changes to the
// build metadata are significant for the purpose of this function:
// it's a different package even if it has the same precedence.
return false
}
// Although "hashes" is declared as a slice, it's logically an
// unordered set. However, we normalize the slice of hashes when
// recieving it in NewProviderLock, so we can just do a simple
// item-by-item equality test here.
if len(thisLock.hashes) != len(otherLock.hashes) {
return false
}
for i := range thisLock.hashes {
if thisLock.hashes[i] != otherLock.hashes[i] {
return false
}
}
}
// We don't need to worry about providers that are in "other" but not
// in the receiver, because we tested the lengths being equal above.
return true
}
// Empty returns true if the given Locks object contains no actual locks.
//
// UI code might wish to use this to distinguish a lock file being
// written for the first time from subsequent updates to that lock file.
func (l *Locks) Empty() bool {
return len(l.providers) == 0
}
// DeepCopy creates a new Locks that represents the same information as the
// receiver but does not share memory for any parts of the structure that.
// are mutable through methods on Locks.
//
// Note that this does _not_ create deep copies of parts of the structure
// that are technically mutable but are immutable by convention, such as the
// array underlying the slice of version constraints. Callers may mutate the
// resulting data structure only via the direct methods of Locks.
func (l *Locks) DeepCopy() *Locks {
ret := NewLocks()
for addr, lock := range l.providers {
var hashes []getproviders.Hash
if len(lock.hashes) > 0 {
hashes = make([]getproviders.Hash, len(lock.hashes))
copy(hashes, lock.hashes)
}
ret.SetProvider(addr, lock.version, lock.versionConstraints, hashes)
}
return ret
}
// ProviderLock represents lock information for a specific provider.
type ProviderLock struct {
// addr is the address of the provider this lock applies to.
addr addrs.Provider
// version is the specific version that was previously selected, while
// versionConstraints is the constraint that was used to make that
// selection, which we can potentially use to hint to run
// e.g. terraform init -upgrade if a user has changed a version
// constraint but the previous selection still remains valid.
// "version" is therefore authoritative, while "versionConstraints" is
// just for a UI hint and not used to make any real decisions.
version getproviders.Version
versionConstraints getproviders.VersionConstraints
// hashes contains zero or more hashes of packages or package contents
// for the package associated with the selected version across all of
// the supported platforms.
//
// hashes can contain a mixture of hashes in different formats to support
// changes over time. The new-style hash format is to have a string
// starting with "h" followed by a version number and then a colon, like
// "h1:" for the first hash format version. Other hash versions following
// this scheme may come later. These versioned hash schemes are implemented
// in the getproviders package; for example, "h1:" is implemented in
// getproviders.HashV1 .
//
// There is also a legacy hash format which is just a lowercase-hex-encoded
// SHA256 hash of the official upstream .zip file for the selected version.
// We'll allow as that a stop-gap until we can upgrade Terraform Registry
// to support the new scheme, but is non-ideal because we can verify it only
// when we have the original .zip file exactly; we can't verify a local
// directory containing the unpacked contents of that .zip file.
//
// We ideally want to populate hashes for all available platforms at
// once, by referring to the signed checksums file in the upstream
// registry. In that ideal case it's possible to later work with the same
// configuration on a different platform while still verifying the hashes.
// However, installation from any method other than an origin registry
// means we can only populate the hash for the current platform, and so
// it won't be possible to verify a subsequent installation of the same
// provider on a different platform.
hashes []getproviders.Hash
}
// Provider returns the address of the provider this lock applies to.
func (l *ProviderLock) Provider() addrs.Provider {
return l.addr
}
// Version returns the currently-selected version for the corresponding provider.
func (l *ProviderLock) Version() getproviders.Version {
return l.version
}
// VersionConstraints returns the version constraints that were recorded as
// being used to choose the version returned by Version.
//
// These version constraints are not authoritative for future selections and
// are included only so Terraform can detect if the constraints in
// configuration have changed since a selection was made, and thus hint to the
// user that they may need to run terraform init -upgrade to apply the new
// constraints.
func (l *ProviderLock) VersionConstraints() getproviders.VersionConstraints {
return l.versionConstraints
}
// AllHashes returns all of the package hashes that were recorded when this
// lock was created. If no hashes were recorded for that platform, the result
// is a zero-length slice.
//
// If your intent is to verify a package against the recorded hashes, use
// PreferredHashes to get only the hashes which the current version
// of Terraform considers the strongest of the available hashing schemes, one
// of which must match in order for verification to be considered successful.
//
// Do not modify the backing array of the returned slice.
func (l *ProviderLock) AllHashes() []getproviders.Hash {
return l.hashes
}
// PreferredHashes returns a filtered version of the AllHashes return value
// which includes only the strongest of the availabile hash schemes, in
// case legacy hash schemes are deprecated over time but still supported for
// upgrade purposes.
//
// At least one of the given hashes must match for a package to be considered
// valud.
func (l *ProviderLock) PreferredHashes() []getproviders.Hash {
return getproviders.PreferredHashes(l.hashes)
}